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Amateurfunk-Anki/explanations.json
T
imple e5af931c0a Touch up some explanations
2026-05-23 12:13:27 +02:00

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{
"AA101": {
"revision": 1,
"explanation": "Impedance is the AC form of resistance, including resistive and reactive parts, so it is measured in ohms just like resistance.",
"source": "https://50ohm.de/A_spule_2.html",
"confidence": 8
},
"AA102": {
"revision": 1,
"explanation": "Charge is current integrated over time; one coulomb is one ampere-second, so As is the practical unit here.",
"source": "https://50ohm.de/EA_ladung_energie.html",
"confidence": 8
},
"AA103": {
"revision": 1,
"explanation": "Energy is power over time, so it can be expressed as joules in SI terms or as watt-hours in practical electrical use.",
"source": "https://50ohm.de/EA_ladung_energie.html",
"confidence": 8
},
"AA104": {
"revision": 1,
"explanation": "Symbol rate counts transmitted symbols per second, and that rate is measured in baud.",
"source": "https://50ohm.de/NEA_datenuebertragungsdrate.html",
"confidence": 8
},
"AA105": {
"revision": 1,
"explanation": "For power ratios, gain in dB is 10 log10(P2/P1); 10 log10(40) is about 16 dB.",
"source": "https://50ohm.de/A_dezibel_2.html",
"confidence": 8
},
"AA106": {
"revision": 1,
"explanation": "A 16 dB power gain is approximately 40 times; with 1 W drive the output is about 40 W, below the 100 W maximum.",
"source": "https://50ohm.de/A_dezibel_2.html",
"confidence": 8
},
"AA107": {
"revision": 1,
"explanation": "1 W is 0 dBW, and a 10 dB amplifier raises the power level by 10 dB, giving 10 dBW.",
"source": "https://50ohm.de/A_dezibel_2.html",
"confidence": 8
},
"AA108": {
"revision": 1,
"explanation": "dBW is referenced to 1 W, so 20 dBW means 10^(20/10) W = 100 W = 10^2 W.",
"source": "https://50ohm.de/A_dezibel_2.html",
"confidence": 8
},
"AA109": {
"revision": 1,
"explanation": "The amplifier output is 10 W; in dBm that is 10 W = 10000 mW, and 10 log10(10000) = 40 dBm.",
"source": "https://50ohm.de/A_dezibel_2.html",
"confidence": 8
},
"AA110": {
"revision": 1,
"explanation": "dBm is referenced to 1 mW: 0 dBm is 1 mW, +3 dB is about double or 2 mW, and +20 dB is 100 times or 100 mW.",
"source": "https://50ohm.de/A_dezibel_2.html",
"confidence": 8
},
"AA111": {
"revision": 1,
"explanation": "For voltage ratios use 20 log10(U2/U1); 20 log10(15) is about 23.5 dB.",
"source": "https://50ohm.de/A_dezibel_2.html",
"confidence": 8
},
"AA112": {
"revision": 1,
"explanation": "120 dB relative to 1 microvolt per meter is a voltage ratio of 10^(120/20) = 10^6, so the field is 1 V/m.",
"source": "https://50ohm.de/A_dezibel_2.html",
"confidence": 8
},
"AA113": {
"revision": 1,
"explanation": "Each S-step is 6 dB; S4 to S7 is three steps, so 3 x 6 dB = 18 dB.",
"source": "https://50ohm.de/NEA_s_meter.html",
"confidence": 8
},
"AA114": {
"revision": 1,
"explanation": "From S9+20 dB down to S9 removes 20 dB, and from S9 to S8 removes another 6 dB, totaling 26 dB.",
"source": "https://50ohm.de/NEA_s_meter.html",
"confidence": 8
},
"AA115": {
"revision": 1,
"explanation": "1 ppm is one part in one million; 435 MHz divided by 10^6 is 435 Hz.",
"source": "https://50ohm.de/A_frequenzgenauigkeit.html",
"confidence": 8
},
"AA116": {
"revision": 1,
"explanation": "10 ppm at 14.200000 MHz is 14.2 MHz x 10/10^6 = 142 Hz, so the possible frequency is 14.200000 MHz plus or minus 0.000142 MHz.",
"source": "https://50ohm.de/A_frequenzgenauigkeit.html",
"confidence": 8
},
"AB101": {
"revision": 1,
"explanation": "Use $R = rho l/A$ with copper $rho = 0.018 ohm mm2/m$ and $A = pi(0.1 mm)^2 = 0.0314 mm2$; $0.018 x 1.8 / 0.0314$ is about 1.02 ohm.",
"source": "https://50ohm.de/EA_leiterwiderstand.html",
"confidence": 8
},
"AB102": {
"revision": 1,
"explanation": "Rearrange $R = rho l/A$ to $l = RA/rho$; $1.5 ohm x 0.5 mm2 / 0.018 ohm mm2/m$ is about 41.7 m.",
"source": "https://50ohm.de/EA_leiterwiderstand.html",
"confidence": 8
},
"AB103": {
"revision": 1,
"explanation": "In metals, higher temperature increases lattice vibration and electron scattering, so resistance normally rises with a positive temperature coefficient.",
"source": "https://50ohm.de/EA_leiterwiderstand.html",
"confidence": 8
},
"AB104": {
"revision": 1,
"explanation": "Semiconductors such as silicon are poor conductors when pure, but heat or small amounts of dopant atoms can provide mobile charge carriers.",
"source": "https://50ohm.de/A_halbleiter_2.html",
"confidence": 8
},
"AB105": {
"revision": 1,
"explanation": "Doping means deliberately adding atoms with different valence to a semiconductor so extra electrons or holes become available as charge carriers.",
"source": "https://50ohm.de/A_halbleiter_2.html",
"confidence": 8
},
"AB106": {
"revision": 1,
"explanation": "N-type material is doped to have extra mobile electrons; electrons are the majority carriers.",
"source": "https://50ohm.de/A_halbleiter_2.html",
"confidence": 8
},
"AB107": {
"revision": 1,
"explanation": "P-type material is doped to create mobile holes; holes are the majority carriers.",
"source": "https://50ohm.de/A_halbleiter_2.html",
"confidence": 8
},
"AB108": {
"revision": 1,
"explanation": "At the PN junction, electrons diffuse from the N side and recombine with holes on the P side, leaving a depleted insulating region at the boundary.",
"source": "https://50ohm.de/A_halbleiter_2.html",
"confidence": 7
},
"AB109": {
"revision": 1,
"explanation": "The shown polarity reverse-biases the diode, pulling majority carriers away from the junction, so the depletion region widens.",
"source": "https://50ohm.de/NEA_halbleiter_2.html",
"confidence": 7
},
"AB201": {
"revision": 1,
"explanation": "A voltage source should hold voltage constant, which requires low internal resistance; a current source should hold current constant, which requires high internal resistance.",
"source": "https://50ohm.de/A_slide_a_strom_spannungsversorgung.html",
"confidence": 8
},
"AB202": {
"revision": 1,
"explanation": "Maximum power transfer occurs when the load resistance equals the source internal resistance.",
"source": "https://50ohm.de/A_slide_a_strom_spannungsversorgung.html",
"confidence": 8
},
"AB203": {
"revision": 1,
"explanation": "Voltage matching minimizes voltage drop inside the source, so the load resistance must be much larger than the source internal resistance.",
"source": "https://50ohm.de/A_slide_a_strom_spannungsversorgung.html",
"confidence": 8
},
"AB204": {
"revision": 1,
"explanation": "Current matching uses a source whose internal resistance is much larger than the load, so the load current stays nearly constant.",
"source": "https://50ohm.de/A_slide_a_strom_spannungsversorgung.html",
"confidence": 8
},
"AB205": {
"revision": 1,
"explanation": "The load current is $4.8 V / 1.2 ohm = 4 A$ and the source drops 0.2 V internally, so $R_i = 0.2 V / 4 A = 0.05 ohm$.",
"source": "https://50ohm.de/EA_innenwiderstand.html",
"confidence": 8
},
"AB206": {
"revision": 1,
"explanation": "The internal voltage drop is $13.5 V - 12.4 V = 1.1 V$; dividing by 0.9 A gives about 1.22 ohm.",
"source": "https://50ohm.de/EA_innenwiderstand.html",
"confidence": 8
},
"AB207": {
"revision": 1,
"explanation": "The terminal voltage falls by 0.5 V at 2 A, so $R_i = 0.5 V / 2 A = 0.25 ohm$.",
"source": "https://50ohm.de/EA_innenwiderstand.html",
"confidence": 8
},
"AB208": {
"revision": 1,
"explanation": "The voltage drop is 0.2 V at 20 A, so $R_i = 0.2 V / 20 A = 0.01 ohm = 10 milliohm$.",
"source": "https://50ohm.de/EA_innenwiderstand.html",
"confidence": 8
},
"AB209": {
"revision": 1,
"explanation": "The six 2 V cells are in series, so voltages add to 12 V while the ampere-hour capacity remains that of one cell, 10 Ah.",
"source": "https://50ohm.de/A_akku.html",
"confidence": 7
},
"AB210": {
"revision": 1,
"explanation": "The mAh value on an accumulator pack states how much charge it can nominally deliver, so it is the nominal capacity.",
"source": "https://50ohm.de/A_akku.html",
"confidence": 8
},
"AB211": {
"revision": 1,
"explanation": "Discharging only down to 10 percent leaves 90 percent usable: $0.9 x 60 Ah = 54 Ah$; $54 Ah / 0.8 A = 67.5 h$.",
"source": "https://50ohm.de/A_akku.html",
"confidence": 8
},
"AB212": {
"revision": 1,
"explanation": "A solar cell converts incident light or other radiation energy directly into electrical energy by freeing charge carriers.",
"source": "https://50ohm.de/EA_photovoltaik.html",
"confidence": 8
},
"AB213": {
"revision": 1,
"explanation": "Input power is $12 V x 2 A = 24 W$ and output power is $5 V x 3 A = 15 W$; efficiency is $15/24 = 62.5%$.",
"source": "https://50ohm.de/NEA_spannungswandler.html",
"confidence": 8
},
"AB214": {
"revision": 1,
"explanation": "Input power is $5 V x 3 A = 15 W$ and output power is $12 V x 1 A = 12 W$; efficiency is $12/15 = 80%$.",
"source": "https://50ohm.de/NEA_spannungswandler.html",
"confidence": 8
},
"AB301": {
"revision": 1,
"explanation": "For a sine current, $I_eff = I_max / sqrt(2)$; power is $I_eff^2 R = (0.5/sqrt(2))^2 x 20 = 2.5 W$.",
"source": "https://50ohm.de/EA_wechselstrom_leistung.html",
"confidence": 8
},
"AB302": {
"revision": 1,
"explanation": "Point X3 is three quarters of a cycle after zero, which is 270 degrees or $3 pi / 2$ radians.",
"source": "https://50ohm.de/NEA_slide_nea_bauelemente.html",
"confidence": 7
},
"AB303": {
"revision": 1,
"explanation": "The two sine waves are shifted by one eighth of a full cycle; $360 degrees / 8 = 45 degrees$.",
"source": "https://50ohm.de/NEA_slide_nea_bauelemente.html",
"confidence": 7
},
"AB401": {
"revision": 2,
"explanation": "Harmonics are integer multiples of a fundamental frequency: first harmonic is the fundamental, second is twice it, and so on.",
"source": "https://50ohm.de/A_slide_a_sender.html",
"confidence": 8
},
"AB402": {
"revision": 3,
"explanation": "Overtones count only the harmonics above the fundamental: 1st overtone = 2nd harmonic, 2nd overtone = 3rd harmonic, 3rd overtone = 4th harmonic.",
"source": "https://50ohm.de/A_slide_a_sender.html",
"confidence": 8
},
"AB403": {
"revision": 2,
"explanation": "A non-sinusoidal periodic waveform can be decomposed into its fundamental plus integer-multiple overtones.",
"source": "https://50ohm.de/A_slide_a_sender.html",
"confidence": 7
},
"AB404": {
"revision": 1,
"explanation": "An ideal sine wave has only one spectral line at its fundamental frequency, so the matching spectrum contains a single component.",
"source": "https://50ohm.de/NEA_fourier_transformation.html",
"confidence": 7
},
"AB405": {
"revision": 1,
"explanation": "A non-sinusoidal periodic signal has a fundamental plus harmonic lines, so the matching spectrum shows multiple discrete components at integer multiples.",
"source": "https://50ohm.de/NEA_fourier_transformation.html",
"confidence": 7
},
"AB406": {
"revision": 1,
"explanation": "A spectrum with only one line corresponds to a pure sinusoidal time-domain signal.",
"source": "https://50ohm.de/NEA_fourier_transformation.html",
"confidence": 7
},
"AB407": {
"revision": 1,
"explanation": "The shown harmonic spectrum corresponds to the periodic non-sinusoidal waveform whose components line up with those harmonic amplitudes.",
"source": "https://50ohm.de/NEA_fourier_transformation.html",
"confidence": 7
},
"AB408": {
"revision": 1,
"explanation": "White noise has roughly constant power per hertz, so the total received noise power is proportional to receiver bandwidth.",
"source": "https://50ohm.de/A_rauschen.html",
"confidence": 8
},
"AB409": {
"revision": 1,
"explanation": "Noise power scales with bandwidth; changing from 2.5 kHz to 0.5 kHz is a factor of 5 reduction, and 10 log10(5) is about 7 dB.",
"source": "https://50ohm.de/A_rauschen.html",
"confidence": 8
},
"AB501": {
"revision": 1,
"explanation": "Stored energy in watt-hours is voltage times ampere-hour capacity: $12 V x 5 Ah = 60 Wh$.",
"source": "https://50ohm.de/A_akku.html",
"confidence": 8
},
"AB502": {
"revision": 1,
"explanation": "Power is $230 V x 0.63 A = 144.9 W$; over 7 h this is $144.9 W x 7 h = 1014 Wh$, about 1.01 kWh.",
"source": "https://50ohm.de/EA_ladung_energie.html",
"confidence": 8
},
"AB503": {
"revision": 1,
"explanation": "The resistor has $P = U^2/R = 10^2/100 = 1 W$; over one hour that is 1 Wh, equal to 3600 J.",
"source": "https://50ohm.de/EA_ladung_energie.html",
"confidence": 7
},
"AB601": {
"revision": 1,
"explanation": "In metal conductors the physical current direction is the electron motion, from the negative pole toward the positive pole, opposite conventional current.",
"source": "https://50ohm.de/NEA_physikalische_stromrichtung.html",
"confidence": 7
},
"AC101": {
"revision": 1,
"explanation": "In an ideal capacitor the current is proportional to the rate of voltage change, so current reaches its extrema a quarter cycle before voltage: it leads by 90 degrees.",
"source": "https://50ohm.de/A_kondensator_2.html",
"confidence": 8
},
"AC102": {
"revision": 1,
"explanation": "Capacitive reactance is negative in AC sign convention, and its magnitude is $1/(2 pi f C)$, so it depends on frequency and capacitance.",
"source": "https://50ohm.de/NEA_kondensator_2.html",
"confidence": 8
},
"AC103": {
"revision": 1,
"explanation": "A pure reactance stores and returns energy instead of converting it to heat, so the ideal reactive resistance has no heat loss.",
"source": "https://50ohm.de/A_kondensator_2.html",
"confidence": 8
},
"AC104": {
"revision": 1,
"explanation": "Use $X_C = 1/(2 pi f C)$; with 100 MHz and 10 pF this gives about 159 ohm.",
"source": "https://50ohm.de/NEA_kondensator_2.html",
"confidence": 8
},
"AC105": {
"revision": 1,
"explanation": "Use $X_C = 1/(2 pi f C)$; with 145 MHz and 50 pF this is about 22 ohm.",
"source": "https://50ohm.de/NEA_kondensator_2.html",
"confidence": 8
},
"AC106": {
"revision": 1,
"explanation": "Use $X_C = 1/(2 pi f C)$; with 100 MHz and 100 pF this gives about 15.9 ohm.",
"source": "https://50ohm.de/NEA_kondensator_2.html",
"confidence": 8
},
"AC107": {
"revision": 1,
"explanation": "Use $X_C = 1/(2 pi f C)$; with 435 MHz and 100 pF this gives about 3.7 ohm.",
"source": "https://50ohm.de/NEA_kondensator_2.html",
"confidence": 8
},
"AC108": {
"revision": 1,
"explanation": "First find reactance from $X_C = U/I = 16 V / 0.032 A = 500 ohm$; then $C = 1/(2 pi f X_C)$ gives about 6.37 microfarad.",
"source": "https://50ohm.de/NEA_kondensator_2.html",
"confidence": 8
},
"AC109": {
"revision": 1,
"explanation": "Real capacitors are not ideal: dielectric loss and lead or ESR losses convert some energy into heat under AC operation.",
"source": "https://50ohm.de/EA_kondensator_2.html",
"confidence": 8
},
"AC110": {
"revision": 1,
"explanation": "Capacitor loss is commonly described by loss factor tan delta; high loss means low quality factor, with tan delta equal to the reciprocal of Q.",
"source": "https://50ohm.de/EA_kondensator_2.html",
"confidence": 8
},
"AC111": {
"revision": 1,
"explanation": "An ideal capacitor draws reactive current but no real power in steady-state AC, so the real power is approximately zero.",
"source": "https://50ohm.de/A_kondensator_2.html",
"confidence": 8
},
"AC201": {
"revision": 1,
"explanation": "In an ideal inductor the magnetic field opposes current changes, so current lags the applied voltage by 90 degrees.",
"source": "https://50ohm.de/A_spule_2.html",
"confidence": 8
},
"AC202": {
"revision": 1,
"explanation": "Inductive reactance is positive in AC sign convention and has magnitude $X_L = 2 pi f L$, so it depends on frequency and inductance.",
"source": "https://50ohm.de/A_spule_2.html",
"confidence": 8
},
"AC203": {
"revision": 1,
"explanation": "With DC only the winding resistance limits current; with AC the inductive reactance is added, so the total impedance is higher and current is smaller.",
"source": "https://50ohm.de/A_spule_2.html",
"confidence": 8
},
"AC204": {
"revision": 1,
"explanation": "Use $X_L = 2 pi f L$; $2 pi x 100 MHz x 3 microhenry$ is about 1885 ohm.",
"source": "https://50ohm.de/A_spule_2.html",
"confidence": 8
},
"AC205": {
"revision": 1,
"explanation": "For a core with AL value, $L = N^2 x AL$; $14^2 x 1.5 nH = 294 nH = 0.294 microhenry$.",
"source": "https://50ohm.de/A_spule_2.html",
"confidence": 8
},
"AC206": {
"revision": 1,
"explanation": "Use $L = N^2 x AL$; $300^2 x 1250 nH = 112500000 nH = 112.5 mH$.",
"source": "https://50ohm.de/A_spule_2.html",
"confidence": 8
},
"AC207": {
"revision": 1,
"explanation": "Rearrange to $N = sqrt(L/AL)$; $sqrt(2 mH / 250 nH) = sqrt(8000)$, about 89 turns.",
"source": "https://50ohm.de/A_spule_2.html",
"confidence": 8
},
"AC208": {
"revision": 1,
"explanation": "Rearrange to $N = sqrt(L/AL)$; $sqrt(12 microhenry / 30 nH) = sqrt(400) = 20 turns$.",
"source": "https://50ohm.de/A_spule_2.html",
"confidence": 8
},
"AC209": {
"revision": 1,
"explanation": "Coil losses are represented by an equivalent series resistance; the loss factor tan delta is used and equals the reciprocal of the quality factor Q.",
"source": "https://50ohm.de/A_spule_2.html",
"confidence": 8
},
"AC210": {
"revision": 1,
"explanation": "A conductive metal enclosure shields the electric field around the tuned-circuit coil and reduces unwanted radiation from it.",
"source": "https://50ohm.de/A_spule_2.html",
"confidence": 8
},
"AC211": {
"revision": 1,
"explanation": "A choke core is normally ferrite because ferrite gives high magnetic permeability and high RF loss for unwanted common-mode currents.",
"source": "https://50ohm.de/A_spule_2.html",
"confidence": 7
},
"AC301": {
"revision": 1,
"explanation": "Mutual induction needs a changing magnetic field, so a changing current in a magnetically coupled neighboring coil induces voltage in the other coil.",
"source": "https://50ohm.de/A_uebertrager_2.html",
"confidence": 8
},
"AC302": {
"revision": 1,
"explanation": "With losses neglected, primary and secondary power are equal: $6 V x 1.15 A = 6.9 W$, and $6.9 W / 230 V = 0.030 A$.",
"source": "https://50ohm.de/A_uebertrager_2.html",
"confidence": 8
},
"AC303": {
"revision": 1,
"explanation": "Impedance transforms with the square of the turns ratio; with 1:4, the input sees $16 kOhm / 4^2 = 1 kOhm$.",
"source": "https://50ohm.de/A_uebertrager_2.html",
"confidence": 7
},
"AC304": {
"revision": 1,
"explanation": "The same 1:4 transformer reflects the secondary load by a factor of 16, so $6.4 kOhm / 16 = 0.4 kOhm$ at a-b.",
"source": "https://50ohm.de/A_uebertrager_2.html",
"confidence": 7
},
"AC305": {
"revision": 1,
"explanation": "The impedance ratio is $450/50 = 9$; turns ratio is the square root of impedance ratio, so $sqrt(9) = 3$.",
"source": "https://50ohm.de/A_uebertrager_2.html",
"confidence": 8
},
"AC306": {
"revision": 1,
"explanation": "A 2.5 kOhm load against 50 ohm is about a 50:1 impedance ratio, close to 49:1, so the turns ratio is about 1:7.",
"source": "https://50ohm.de/A_uebertrager_2.html",
"confidence": 8
},
"AC307": {
"revision": 1,
"explanation": "The wire area is $pi d^2/4 = pi x 0.5^2/4 = 0.196 mm2$; at 2.5 A/mm2 the current is about 0.49 A.",
"source": "https://50ohm.de/A_uebertrager_2.html",
"confidence": 8
},
"AC401": {
"revision": 1,
"explanation": "In forward bias, the depletion region is reduced and electrons can cross the PN junction from the N side to the P side.",
"source": "https://50ohm.de/A_diode_2.html",
"confidence": 8
},
"AC402": {
"revision": 1,
"explanation": "Electrons are the majority carriers in the N region, and in forward operation they move across the junction into the P region.",
"source": "https://50ohm.de/A_diode_2.html",
"confidence": 8
},
"AC403": {
"revision": 1,
"explanation": "As temperature rises, diode saturation current increases, so the forward voltage needed for a given current falls.",
"source": "https://50ohm.de/A_diode_2.html",
"confidence": 8
},
"AC404": {
"revision": 1,
"explanation": "A varicap is reverse-biased; lower reverse voltage makes the depletion region narrower, which increases junction capacitance.",
"source": "https://50ohm.de/A_diode_2.html",
"confidence": 8
},
"AC405": {
"revision": 1,
"explanation": "Antiparallel silicon diodes clip the waveform when either polarity exceeds about 0.6 V, so the output is the sine wave limited at that threshold.",
"source": "https://50ohm.de/A_diode_2.html",
"confidence": 7
},
"AC406": {
"revision": 1,
"explanation": "Germanium diodes have a lower threshold, about 0.3 V, so the same limiter clips the waveform earlier and more strongly than silicon diodes.",
"source": "https://50ohm.de/A_diode_2.html",
"confidence": 7
},
"AC407": {
"revision": 1,
"explanation": "A photodiode generates electron-hole pairs when illuminated and can produce photocurrent from light.",
"source": "https://50ohm.de/A_diode_2.html",
"confidence": 8
},
"AC408": {
"revision": 1,
"explanation": "An optocoupler transfers a signal optically between an LED and a photosensitive device, giving galvanic isolation between the two circuits.",
"source": "https://50ohm.de/A_diode_2.html",
"confidence": 8
},
"AC501": {
"revision": 1,
"explanation": "In a bipolar transistor, a small base current controls a larger collector current, so it is current-controlled.",
"source": "https://50ohm.de/A_transistor_2.html",
"confidence": 8
},
"AC502": {
"revision": 1,
"explanation": "A field-effect transistor controls channel current by the electric field from the gate-source voltage, so it is voltage-controlled.",
"source": "https://50ohm.de/A_transistor_2.html",
"confidence": 8
},
"AC503": {
"revision": 1,
"explanation": "An NPN transistor has an N emitter, P base, and N collector, so the p-doped region is the base.",
"source": "https://50ohm.de/A_transistor_2.html",
"confidence": 8
},
"AC504": {
"revision": 1,
"explanation": "A PNP transistor has a P emitter, N base, and P collector, so the n-doped region is the base.",
"source": "https://50ohm.de/A_transistor_2.html",
"confidence": 8
},
"AC505": {
"revision": 1,
"explanation": "For a bipolar transistor to conduct normally, the base-emitter junction is forward biased.",
"source": "https://50ohm.de/A_transistor_2.html",
"confidence": 8
},
"AC506": {
"revision": 1,
"explanation": "The symbol shows a gate controlling a channel between source and drain, which identifies a field-effect transistor.",
"source": "https://50ohm.de/A_transistor_2.html",
"confidence": 7
},
"AC507": {
"revision": 1,
"explanation": "The continuous channel marks depletion-mode, self-conducting JFETs; the arrow direction distinguishes N-channel from P-channel in the two symbols.",
"source": "https://50ohm.de/A_transistor_2.html",
"confidence": 7
},
"AC508": {
"revision": 1,
"explanation": "The insulated gate identifies a MOSFET, the interrupted channel marks enhancement mode, and the arrow/channel orientation identifies an N-channel device.",
"source": "https://50ohm.de/A_transistor_2.html",
"confidence": 7
},
"AC509": {
"revision": 1,
"explanation": "The correct symbol combines an insulated gate, interrupted enhancement-mode channel, and N-channel arrow orientation.",
"source": "https://50ohm.de/A_transistor_2.html",
"confidence": 7
},
"AC510": {
"revision": 1,
"explanation": "A depletion-mode N-channel MOSFET is recognized by the insulated gate plus continuous channel and N-channel arrow orientation.",
"source": "https://50ohm.de/A_transistor_2.html",
"confidence": 7
},
"AC511": {
"revision": 1,
"explanation": "A depletion-mode P-channel MOSFET has the insulated gate, continuous channel, and the P-channel arrow orientation.",
"source": "https://50ohm.de/A_transistor_2.html",
"confidence": 7
},
"AC512": {
"revision": 1,
"explanation": "FET terminals are named drain, gate, and source; emitter, base, and collector are bipolar-transistor names.",
"source": "https://50ohm.de/A_transistor_2.html",
"confidence": 8
},
"AC513": {
"revision": 1,
"explanation": "The shown FET package labels the channel terminals as drain and source, with the control terminal as gate.",
"source": "https://50ohm.de/A_transistor_2.html",
"confidence": 7
},
"AC514": {
"revision": 1,
"explanation": "The gate-source voltage changes the channel resistance between source and drain, thereby controlling drain current with almost no gate current.",
"source": "https://50ohm.de/A_transistor_2.html",
"confidence": 8
},
"AC515": {
"revision": 1,
"explanation": "Base current is $5 mA / 298 = 16.8 microampere$; with about 0.6 V base-emitter drop, $R_1 = (12 - 0.6) V / 16.8 microampere$, about 680 kOhm.",
"source": "https://50ohm.de/A_transistor_2.html",
"confidence": 7
},
"AC516": {
"revision": 1,
"explanation": "Making the divider current much larger than base current keeps the base voltage mostly set by the divider, so transistor beta and temperature changes disturb the operating point less.",
"source": "https://50ohm.de/A_transistor_2.html",
"confidence": 7
},
"AC517": {
"revision": 1,
"explanation": "Base current is $2 mA/200 = 10 microampere$; R2 carries ten times that, so R1 carries 110 microampere. With 1 V at the emitter, the base is about 1.6 V, giving $R_1 = 8.4 V/110 microampere = 76.4 kOhm$.",
"source": "https://50ohm.de/A_transistor_2.html",
"confidence": 7
},
"AC518": {
"revision": 1,
"explanation": "Base current is 10 microampere and R2 current is 100 microampere, so R1 current is 110 microampere; with the base near 0.6 V, $R_1 = 9.4 V/110 microampere = 85.5 kOhm$.",
"source": "https://50ohm.de/A_transistor_2.html",
"confidence": 7
},
"AC519": {
"revision": 1,
"explanation": "If R1 is open, the base receives no forward bias, the transistor switches off, and with no collector current the collector rises to the supply voltage.",
"source": "https://50ohm.de/A_transistor_2.html",
"confidence": 7
},
"AC520": {
"revision": 1,
"explanation": "If R2 is open, the base is driven too strongly through R1, so the transistor saturates; collector current is then limited mainly by RC and collector voltage falls near saturation voltage.",
"source": "https://50ohm.de/A_transistor_2.html",
"confidence": 7
},
"AC521": {
"revision": 1,
"explanation": "The gate draws negligible current, so the divider gives $U_G = 44 V x 1 kOhm/(10 kOhm + 1 kOhm) = 4 V$; with the source at reference, that is $U_GS$.",
"source": "https://50ohm.de/A_transistor_2.html",
"confidence": 7
},
"AC522": {
"revision": 1,
"explanation": "For a divider, $R_2 = R_1 U_G/(U_B - U_G)$; $10 kOhm x 2.8/(44 - 2.8)$ gives about 680 ohm.",
"source": "https://50ohm.de/A_transistor_2.html",
"confidence": 7
},
"AC523": {
"revision": 1,
"explanation": "Conduction loss is $P = I^2 R$; $25^2 x 0.004 ohm = 2.5 W$.",
"source": "https://50ohm.de/A_transistor_2.html",
"confidence": 8
},
"AC524": {
"revision": 2,
"explanation": "When the switch opens, the inductor tries to maintain its current and reverses the voltage across itself. The flyback diode is wired antiparallel so it forward-conducts at that moment, providing a safe current path and clamping the back-EMF that would otherwise destroy the switching transistor.",
"source": "https://50ohm.de/A_transistor_2.html",
"confidence": 7
},
"AC601": {
"revision": 2,
"explanation": "An integrated circuit combines many circuit elements directly on one semiconductor substrate.",
"source": "https://50ohm.de/A_integrierte_schaltkreise.html",
"confidence": 8
},
"AC602": {
"revision": 2,
"explanation": "An MMIC is monolithic, so active and passive microwave circuit elements are integrated on the same semiconductor substrate.",
"source": "https://50ohm.de/A_integrierte_schaltkreise.html",
"confidence": 8
},
"AC603": {
"revision": 2,
"explanation": "An MMIC amplifier integrates the active device and matching elements, giving broad bandwidth and useful gain with fewer external components.",
"source": "https://50ohm.de/A_integrierte_schaltkreise.html",
"confidence": 8
},
"AC604": {
"revision": 2,
"explanation": "Many MMICs are designed as RF building blocks with standard input and output impedances such as 50 ohm.",
"source": "https://50ohm.de/A_integrierte_schaltkreise.html",
"confidence": 8
},
"AD101": {
"revision": 1,
"explanation": "Series capacitors add by reciprocals: $1/C = 1/100 pF + 1/47 pF + 1/22 pF$, giving about 13.0 pF.",
"source": "https://50ohm.de/A_reihe_parallel_gemischt.html",
"confidence": 8
},
"AD102": {
"revision": 1,
"explanation": "Series inductances add directly: 2200 nH is 2.2 microhenry, 0.033 mH is 33 microhenry, so the sum is 2.2 + 33 + 150 = 185.2 microhenry.",
"source": "https://50ohm.de/A_reihe_parallel_gemischt.html",
"confidence": 8
},
"AD103": {
"revision": 1,
"explanation": "The shown capacitances are effectively parallel, so they add: 100 pF + 1500 pF + 220 pF + 1 pF = 1821 pF.",
"source": "https://50ohm.de/A_reihe_parallel_gemischt.html",
"confidence": 7
},
"AD104": {
"revision": 1,
"explanation": "At 1 MHz and 1 nF, $X_C$ is about 159 ohm; the series impedance magnitude is $sqrt(100^2 + 159^2)$, about 188 ohm.",
"source": "https://50ohm.de/A_reihe_parallel_gemischt.html",
"confidence": 8
},
"AD105": {
"revision": 1,
"explanation": "At 1 MHz and 100 microhenry, $X_L$ is about 628 ohm; $|Z| = sqrt(100^2 + 628^2)$, about 636 ohm.",
"source": "https://50ohm.de/A_reihe_parallel_gemischt.html",
"confidence": 8
},
"AD106": {
"revision": 1,
"explanation": "If 1 mA flows through R3, the parallel section has 10 V across it; R2 draws another 1 mA, so 2 mA through R1 drops 20 V, making the total 30 V.",
"source": "https://50ohm.de/EA_reihe_parallel_widerstandsnetz_2.html",
"confidence": 7
},
"AD107": {
"revision": 1,
"explanation": "R2 and R3 in parallel give 5 kOhm, in series with R1 gives 15 kOhm; 15 V / 15 kOhm is 1 mA total, split equally so R3 has 0.5 mA.",
"source": "https://50ohm.de/EA_reihe_parallel_widerstandsnetz_2.html",
"confidence": 7
},
"AD108": {
"revision": 1,
"explanation": "The total current is 1 mA, so the parallel section has 5 V across it; R2 power is $5^2/10000 = 0.0025 W = 2.5 mW$.",
"source": "https://50ohm.de/EA_reihe_parallel_widerstandsnetz_2.html",
"confidence": 7
},
"AD109": {
"revision": 1,
"explanation": "The input is 200 ohm plus 100 ohm in parallel with 200 ohm + R; at R = 0 this is about 267 ohm, and at R = 1 kOhm it is about 292 ohm.",
"source": "https://50ohm.de/NEA_slide_nea_reihen_parallelschaltung.html",
"confidence": 7
},
"AD110": {
"revision": 1,
"explanation": "Each side branch is 2.2 kOhm + 220 ohm = 2420 ohm, and two equal branches in parallel give half that value, 1210 ohm.",
"source": "https://50ohm.de/NEA_slide_nea_reihen_parallelschaltung.html",
"confidence": 7
},
"AD111": {
"revision": 1,
"explanation": "A bridge has zero branch voltage when the two divider ratios are equal, which gives $R1/R2 = R3/R4$.",
"source": "https://50ohm.de/EA_brueckenschaltung.html",
"confidence": 7
},
"AD112": {
"revision": 1,
"explanation": "All four resistors are equal, so the two divider midpoints sit at the same potential; the bridge voltage from A to B is 0 V.",
"source": "https://50ohm.de/EA_brueckenschaltung.html",
"confidence": 7
},
"AD113": {
"revision": 1,
"explanation": "The left divider gives point A at 10 V and the right divider gives point B at 1 V, so measured from A to B the bridge voltage is +9 V.",
"source": "https://50ohm.de/EA_brueckenschaltung.html",
"confidence": 7
},
"AD114": {
"revision": 1,
"explanation": "The load is parallel to R2: $2.2 kOhm || 8.2 kOhm$ is about 1.73 kOhm. The divider output is $12 V x 1.73/(10 + 1.73)$, about 1.8 V.",
"source": "https://50ohm.de/A_spannungsteiler_2.html",
"confidence": 7
},
"AD115": {
"revision": 1,
"explanation": "Adding the load lowers the effective lower resistance of the divider, increasing the supply current through R1; with higher current, R1 dissipates more heat.",
"source": "https://50ohm.de/A_spannungsteiler_2.html",
"confidence": 7
},
"AD201": {
"revision": 1,
"explanation": "An RC high-pass cutoff is $f_g = 1/(2 pi R C)$; with 4.7 kOhm and 2.2 nF this is about 15.4 kHz.",
"source": "https://50ohm.de/A_schwingkreis_2.html",
"confidence": 7
},
"AD202": {
"revision": 1,
"explanation": "An RC low-pass has the same cutoff formula, $f_g = 1/(2 pi R C)$; with 10 kOhm and 47 nF this is about 339 Hz.",
"source": "https://50ohm.de/A_schwingkreis_2.html",
"confidence": 7
},
"AD203": {
"revision": 1,
"explanation": "The relevant low-pass is R1 with C1; C2 is supply decoupling and the amplifier input is very high impedance. $1/(2 pi x 4.7 kOhm x 6.8 nF)$ is about 5 kHz.",
"source": "https://50ohm.de/A_schwingkreis_2.html",
"confidence": 7
},
"AD204": {
"revision": 1,
"explanation": "A series resonant circuit has minimum impedance at resonance, while a parallel resonant circuit has maximum impedance there; the correct pairings match those curve shapes.",
"source": "https://50ohm.de/A_slide_a_grundlegende_schaltungen.html",
"confidence": 7
},
"AD205": {
"revision": 1,
"explanation": "The circuit passes only a middle range of frequencies while attenuating frequencies below and above that range, which is the behavior of a band-pass filter.",
"source": "https://50ohm.de/A_slide_a_grundlegende_schaltungen.html",
"confidence": 7
},
"AD206": {
"revision": 1,
"explanation": "At resonance, inductive and capacitive reactances have equal magnitude and opposite sign, so their reactive effects cancel.",
"source": "https://50ohm.de/A_schwingkreis_2.html",
"confidence": 8
},
"AD207": {
"revision": 1,
"explanation": "In a series resonant circuit the L and C reactances cancel, leaving only the real series resistance R as the impedance.",
"source": "https://50ohm.de/A_schwingkreis_2.html",
"confidence": 7
},
"AD208": {
"revision": 1,
"explanation": "Use Thomson's formula $f = 1/(2 pi sqrt(L C))$; with 1.2 microhenry and 6.8 pF the result is about 55.7 MHz.",
"source": "https://50ohm.de/A_schwingkreis_2.html",
"confidence": 7
},
"AD209": {
"revision": 1,
"explanation": "The resistor does not set the ideal resonant frequency; $1/(2 pi sqrt(10 microhenry x 1 nF))$ is about 1.592 MHz.",
"source": "https://50ohm.de/A_schwingkreis_2.html",
"confidence": 7
},
"AD210": {
"revision": 1,
"explanation": "Using $f = 1/(2 pi sqrt(L C))$ with 100 microhenry and 0.01 microfarad gives about 159 kHz.",
"source": "https://50ohm.de/A_schwingkreis_2.html",
"confidence": 7
},
"AD211": {
"revision": 1,
"explanation": "For the parallel resonant circuit, $f = 1/(2 pi sqrt(2.2 microhenry x 56 pF))$, giving about 14.34 MHz.",
"source": "https://50ohm.de/A_schwingkreis_2.html",
"confidence": 7
},
"AD212": {
"revision": 1,
"explanation": "The parallel capacitances add to about 1.82 nF; with 1.2 mH, $1/(2 pi sqrt(L C))$ gives about 107.7 kHz.",
"source": "https://50ohm.de/A_schwingkreis_2.html",
"confidence": 7
},
"AD213": {
"revision": 1,
"explanation": "Resonant frequency is inversely proportional to $sqrt(L C)$, so using a smaller inductance raises the frequency.",
"source": "https://50ohm.de/A_schwingkreis_2.html",
"confidence": 8
},
"AD214": {
"revision": 1,
"explanation": "Fewer turns reduce coil inductance, and lower inductance increases the resonant frequency.",
"source": "https://50ohm.de/A_schwingkreis_2.html",
"confidence": 8
},
"AD215": {
"revision": 1,
"explanation": "Increasing capacitance increases the LC product, so the resonant frequency decreases.",
"source": "https://50ohm.de/A_schwingkreis_2.html",
"confidence": 8
},
"AD216": {
"revision": 1,
"explanation": "Pushing the coil turns closer together increases inductance, and higher inductance lowers the resonant frequency.",
"source": "https://50ohm.de/A_schwingkreis_2.html",
"confidence": 8
},
"AD217": {
"revision": 1,
"explanation": "A ferrite core increases coil inductance, and the larger L in the LC formula lowers the resonant frequency.",
"source": "https://50ohm.de/A_schwingkreis_2.html",
"confidence": 8
},
"AD218": {
"revision": 1,
"explanation": "Moving the potentiometer toward X raises the reverse voltage on the varicap; higher reverse voltage lowers its capacitance, so the LC resonant frequency rises.",
"source": "https://50ohm.de/A_schwingkreis_2.html",
"confidence": 7
},
"AD219": {
"revision": 1,
"explanation": "Bandwidth is read as the frequency difference between the two points on the curve at the specified level; at -60 dB the marked span is about 4 kHz.",
"source": "https://50ohm.de/A_slide_a_grundlegende_schaltungen.html",
"confidence": 7
},
"AD220": {
"revision": 1,
"explanation": "Filter bandwidth is the difference between the two frequencies where the voltage has fallen to 0.7 of the resonant maximum, the -3 dB points.",
"source": "https://50ohm.de/A_schwingkreis_2.html",
"confidence": 8
},
"AD221": {
"revision": 1,
"explanation": "SSB speech typically needs about 2.4 to 2.7 kHz of filter bandwidth, so a 2.7 kHz crystal filter fits SSB operation.",
"source": "https://50ohm.de/A_slide_a_empfaenger.html",
"confidence": 8
},
"AD222": {
"revision": 1,
"explanation": "CW reception benefits from a narrow filter; 500 Hz is typical for separating Morse signals from nearby stations.",
"source": "https://50ohm.de/A_slide_a_empfaenger.html",
"confidence": 8
},
"AD223": {
"revision": 1,
"explanation": "For a series resonant circuit, bandwidth is $B = R/(2 pi L)$; $10/(2 pi x 100 microhenry)$ is about 15.9 kHz.",
"source": "https://50ohm.de/A_schwingkreis_2.html",
"confidence": 8
},
"AD224": {
"revision": 1,
"explanation": "For the parallel case, $B = 1/(2 pi R C)$; with 1 kOhm and 56 pF this is about 2.84 MHz.",
"source": "https://50ohm.de/A_schwingkreis_2.html",
"confidence": 8
},
"AD225": {
"revision": 1,
"explanation": "For the series circuit, Q is resonant frequency divided by bandwidth; about 159 kHz / 15.9 kHz = 10.",
"source": "https://50ohm.de/A_schwingkreis_2.html",
"confidence": 8
},
"AD226": {
"revision": 1,
"explanation": "For the parallel circuit, Q is resonant frequency divided by bandwidth; about 14.34 MHz / 2.84 MHz is about 5.",
"source": "https://50ohm.de/A_schwingkreis_2.html",
"confidence": 8
},
"AD227": {
"revision": 1,
"explanation": "Looser coupling gives a narrower, lower transfer curve; in the shown family, curve c is less coupled than curve a.",
"source": "https://50ohm.de/A_schwingkreis_2.html",
"confidence": 7
},
"AD228": {
"revision": 1,
"explanation": "Critical coupling gives the flattest single peak at maximum useful width, while overcritical coupling creates the double-humped response; those are curves b and a respectively.",
"source": "https://50ohm.de/A_schwingkreis_2.html",
"confidence": 7
},
"AD229": {
"revision": 1,
"explanation": "Critical coupling is the coupling just before the response splits into a double hump: the curve has maximum width while the resonance maximum is still flat.",
"source": "https://50ohm.de/A_schwingkreis_2.html",
"confidence": 8
},
"AD301": {
"revision": 1,
"explanation": "In each series string the cell voltages add, giving $30 x 0.6 V = 18 V$; four identical strings in parallel add their short-circuit currents to 4 A.",
"source": "https://50ohm.de/A_slide_a_strom_spannungsversorgung.html",
"confidence": 7
},
"AD302": {
"revision": 1,
"explanation": "The unloaded smoothing capacitor charges close to the peak of the secondary AC voltage; about 15 V RMS times $sqrt(2)$ gives roughly 21 V.",
"source": "https://50ohm.de/A_slide_a_strom_spannungsversorgung.html",
"confidence": 7
},
"AD303": {
"revision": 1,
"explanation": "A 20:1 transformer gives 230 V / 20 = 11.5 V RMS; the peak is about 16.3 V, and adding 50 percent safety gives about 24.4 V, so choose at least 25 V.",
"source": "https://50ohm.de/A_slide_a_strom_spannungsversorgung.html",
"confidence": 7
},
"AD304": {
"revision": 1,
"explanation": "A 5:1 transformer gives 46 V RMS, or about 65 V peak; the diode must withstand about twice that peak plus 20 percent, giving about 156 V.",
"source": "https://50ohm.de/A_slide_a_strom_spannungsversorgung.html",
"confidence": 7
},
"AD305": {
"revision": 1,
"explanation": "In a bridge rectifier, two diodes conduct on each half-cycle so current through the load always has the same polarity; the correct diagram has all four diodes oriented for that path.",
"source": "https://50ohm.de/NEA_brueckengleichrichter.html",
"confidence": 7
},
"AD306": {
"revision": 1,
"explanation": "The secondary peak is the mains peak divided by 8: $230 V x 1.414 / 8$ is about 40.6 V, which is the unloaded capacitor voltage.",
"source": "https://50ohm.de/NEA_brueckengleichrichter.html",
"confidence": 7
},
"AD307": {
"revision": 1,
"explanation": "A full-wave rectifier uses both half-cycles and routes them through the load with the indicated same output polarity.",
"source": "https://50ohm.de/NEA_vollweggleichrichter.html",
"confidence": 7
},
"AD308": {
"revision": 1,
"explanation": "The rectifier output is pulsating DC: the negative half-cycles are folded to the same polarity rather than appearing as negative voltage.",
"source": "https://50ohm.de/NEA_vollweggleichrichter.html",
"confidence": 7
},
"AD309": {
"revision": 1,
"explanation": "The ripple span is the difference between the high and low points, 3 V, and a full-wave rectifier on 50 Hz mains produces ripple at 100 Hz.",
"source": "https://50ohm.de/A_slide_a_strom_spannungsversorgung.html",
"confidence": 7
},
"AD310": {
"revision": 1,
"explanation": "A full-wave rectifier produces one output pulse for each half-cycle, so 50 Hz mains becomes 100 Hz ripple frequency.",
"source": "https://50ohm.de/NEA_vollweggleichrichter.html",
"confidence": 8
},
"AD311": {
"revision": 1,
"explanation": "In a switch-mode supply the electronic switch controls energy transfer by changing pulse width, so block E acts as the pulse-width modulator.",
"source": "https://50ohm.de/A_schaltnetzteil_2.html",
"confidence": 7
},
"AD312": {
"revision": 1,
"explanation": "The fast switching action produces harmonics and broadband unwanted spectral components, which is the main EMC disadvantage of the shown switch-mode supply.",
"source": "https://50ohm.de/A_schaltnetzteil_2.html",
"confidence": 7
},
"AD313": {
"revision": 2,
"explanation": "Spurs spaced 120 kHz apart across the spectrum point to a switch-mode supply: its switching frequency and harmonics radiate at multiples of that fundamental rate.",
"source": "https://50ohm.de/A_schaltnetzteil_2.html",
"confidence": 8
},
"AD314": {
"revision": 1,
"explanation": "A mains input filter uses a common-mode choke and capacitors to keep switching interference from being conducted back into the power network.",
"source": "https://50ohm.de/A_schaltnetzteil_2.html",
"confidence": 7
},
"AD315": {
"revision": 1,
"explanation": "The Z-diode regulator clamps the output near the Zener voltage, so the output between A and B is approximately 5 V despite the varying input.",
"source": "https://50ohm.de/A_spannungsstabilisierung.html",
"confidence": 7
},
"AD316": {
"revision": 1,
"explanation": "A linear regulator needs headroom: its input voltage must be higher than the regulated output voltage so the pass element can control the drop.",
"source": "https://50ohm.de/A_spannungsstabilisierung.html",
"confidence": 7
},
"AD317": {
"revision": 1,
"explanation": "A fixed 12 V regulator absorbs the allowed input variation as internal voltage drop, so the output variation is nearly zero while it remains in regulation.",
"source": "https://50ohm.de/A_spannungsstabilisierung.html",
"confidence": 7
},
"AD318": {
"revision": 1,
"explanation": "The load current is $5 V / 10 ohm = 0.5 A$ and the regulator drops $13.8 V - 5 V = 8.8 V$; loss is $8.8 V x 0.5 A = 4.4 W$.",
"source": "https://50ohm.de/A_spannungsstabilisierung.html",
"confidence": 7
},
"AD319": {
"revision": 1,
"explanation": "A linear regulator dissipates the voltage drop times current: $(13.8 V - 9 V) x 0.9 A = 4.32 W$.",
"source": "https://50ohm.de/A_spannungsstabilisierung.html",
"confidence": 8
},
"AD320": {
"revision": 1,
"explanation": "Efficiency is output power over input power: $5 V x 0.450 A$ divided by $13.8 V x 0.455 A$ is about 0.36.",
"source": "https://50ohm.de/A_spannungsstabilisierung.html",
"confidence": 8
},
"AD321": {
"revision": 1,
"explanation": "The load power is $4.7 V x 10 mA = 47 mW$; input power is $13.8 V x (10 + 15) mA = 345 mW$, so efficiency is about 0.14.",
"source": "https://50ohm.de/A_spannungsstabilisierung.html",
"confidence": 7
},
"AD322": {
"revision": 1,
"explanation": "A Bias-T combines DC feed and RF signal on one cable while separating them again at the ports with an inductor and capacitor.",
"source": "https://50ohm.de/NEA_fernspeiseweiche.html",
"confidence": 8
},
"AD323": {
"revision": 1,
"explanation": "The circuit combines a DC feed path through an inductor with an RF path through a coupling capacitor, which is the structure of a Bias-T.",
"source": "https://50ohm.de/NEA_fernspeiseweiche.html",
"confidence": 7
},
"AD324": {
"revision": 1,
"explanation": "C1 is the RF coupling capacitor toward the receiver; it passes RF but blocks the DC supply from reaching the receiver input.",
"source": "https://50ohm.de/NEA_fernspeiseweiche.html",
"confidence": 7
},
"AD325": {
"revision": 1,
"explanation": "The Bias-T inductor is in the DC feed path, so it must safely carry the supply current for the remote device.",
"source": "https://50ohm.de/NEA_fernspeiseweiche.html",
"confidence": 7
},
"AD401": {
"revision": 1,
"explanation": "The collector is the AC-common terminal and the output is taken from the emitter, so this is the collector configuration, also called an emitter follower.",
"source": "https://50ohm.de/A_kollektorschaltung.html",
"confidence": 7
},
"AD402": {
"revision": 1,
"explanation": "An emitter follower has voltage gain just below unity because the emitter follows the base voltage, and it is non-inverting, so the phase shift is 0 degrees.",
"source": "https://50ohm.de/A_kollektorschaltung.html",
"confidence": 7
},
"AD403": {
"revision": 1,
"explanation": "A collector configuration buffers a high-impedance source into a low-impedance load; its current gain is useful even though voltage gain is below one.",
"source": "https://50ohm.de/A_kollektorschaltung.html",
"confidence": 7
},
"AD404": {
"revision": 1,
"explanation": "Because it has high input impedance and low output impedance, an emitter follower can isolate an oscillator from changing load impedance.",
"source": "https://50ohm.de/A_kollektorschaltung.html",
"confidence": 7
},
"AD405": {
"revision": 1,
"explanation": "In a collector configuration the emitter voltage rises and falls with the base signal, so input and output have the same phase.",
"source": "https://50ohm.de/A_kollektorschaltung.html",
"confidence": 8
},
"AD406": {
"revision": 1,
"explanation": "Without DC bias the transistor conducts only when the base-emitter voltage exceeds about 0.6 V; the collector voltage then dips, so the output is a clipped, inverted pulse-like waveform.",
"source": "https://50ohm.de/A_emitterschaltung.html",
"confidence": 7
},
"AD407": {
"revision": 1,
"explanation": "In an emitter configuration, increasing base current increases collector current and therefore the voltage drop across the collector resistor; the collector output voltage moves oppositely, giving 180 degrees phase shift.",
"source": "https://50ohm.de/A_emitterschaltung.html",
"confidence": 8
},
"AD408": {
"revision": 1,
"explanation": "The emitter-stage output is taken at the collector, so the collector waveform is inverted relative to the input while the bias and coupling points keep their shown DC roles.",
"source": "https://50ohm.de/A_emitterschaltung.html",
"confidence": 7
},
"AD409": {
"revision": 1,
"explanation": "The emitter is the common reference for input and output, with the output taken at the collector through a coupling capacitor, which identifies an emitter configuration.",
"source": "https://50ohm.de/A_emitterschaltung.html",
"confidence": 7
},
"AD410": {
"revision": 1,
"explanation": "A bypassed emitter stage can provide large voltage gain, and the collector output is inverted relative to the base input, so the phase shift is 180 degrees.",
"source": "https://50ohm.de/A_emitterschaltung.html",
"confidence": 7
},
"AD411": {
"revision": 1,
"explanation": "R1 and R2 form a voltage divider feeding the base, setting the transistor's DC bias point before the AC signal is applied.",
"source": "https://50ohm.de/A_emitterschaltung.html",
"confidence": 7
},
"AD412": {
"revision": 1,
"explanation": "The coupling capacitors pass the AC signal into and out of the stage while blocking the DC bias voltages from adjacent circuits.",
"source": "https://50ohm.de/A_emitterschaltung.html",
"confidence": 7
},
"AD413": {
"revision": 1,
"explanation": "The emitter bypass capacitor shorts the emitter resistor for AC, reducing emitter degeneration and therefore maximizing AC voltage gain.",
"source": "https://50ohm.de/A_emitterschaltung.html",
"confidence": 7
},
"AD414": {
"revision": 1,
"explanation": "Removing the emitter bypass capacitor leaves the emitter resistor active for AC feedback, so emitter degeneration lowers the voltage gain.",
"source": "https://50ohm.de/A_emitterschaltung.html",
"confidence": 7
},
"AD415": {
"revision": 1,
"explanation": "With no emitter bypass capacitor, the emitter resistor provides negative feedback and the stage gain drops from a large value to roughly the resistor-ratio value, about 10 here.",
"source": "https://50ohm.de/A_emitterschaltung.html",
"confidence": 7
},
"AD416": {
"revision": 1,
"explanation": "Moving the bias point upward increases the conduction angle: C is below cutoff most of the cycle, B sits at cutoff, AB is slightly above it, and A conducts for the whole cycle.",
"source": "https://50ohm.de/A_verstaerker_klasse.html",
"confidence": 7
},
"AD417": {
"revision": 1,
"explanation": "A bipolar transistor's collector current is controlled by base-emitter voltage, so raising that voltage in B operation drives the transistor harder and greatly increases collector current.",
"source": "https://50ohm.de/A_verstaerker_klasse.html",
"confidence": 8
},
"AD418": {
"revision": 1,
"explanation": "Class C is biased below cutoff; with no drive the transistor does not conduct, so the quiescent current is approximately zero.",
"source": "https://50ohm.de/A_verstaerker_klasse.html",
"confidence": 8
},
"AD419": {
"revision": 1,
"explanation": "Class A keeps the device conducting over the full signal cycle, giving good linearity and low harmonics at the cost of high quiescent current and poor efficiency around 40%.",
"source": "https://50ohm.de/A_verstaerker_klasse.html",
"confidence": 8
},
"AD420": {
"revision": 1,
"explanation": "Class B biases near cutoff so quiescent current is very small; with push-pull operation it can be fairly linear and efficient, up to about 80%.",
"source": "https://50ohm.de/A_verstaerker_klasse.html",
"confidence": 8
},
"AD421": {
"revision": 1,
"explanation": "Class C conducts for less than half the cycle, so it is very efficient but strongly nonlinear, producing many harmonics and no quiescent current.",
"source": "https://50ohm.de/A_verstaerker_klasse.html",
"confidence": 8
},
"AD422": {
"revision": 1,
"explanation": "SSB needs linear amplification because information is carried in amplitude and phase; class C is nonlinear, while A, AB, and B can be used for linear RF power stages.",
"source": "https://50ohm.de/A_verstaerker_klasse.html",
"confidence": 8
},
"AD423": {
"revision": 1,
"explanation": "Overdrive pushes a nominally linear AB amplifier into nonlinear operation; distorted SSB creates unwanted side products that appear as splatter on adjacent frequencies.",
"source": "https://50ohm.de/A_verstaerker_klasse.html",
"confidence": 8
},
"AD424": {
"revision": 1,
"explanation": "The DC input power is $50 V x 2 A = 100 W$; class A efficiency is about 40%, so expected RF output is about $0.4 x 100 W = 40 W$.",
"source": "https://50ohm.de/A_verstaerker_wirkungsgrad.html",
"confidence": 8
},
"AD425": {
"revision": 1,
"explanation": "The DC input power is $50 V x 2 A = 100 W$; using about 85% efficiency for class C gives about $0.85 x 100 W = 85 W$ RF output.",
"source": "https://50ohm.de/A_verstaerker_wirkungsgrad.html",
"confidence": 8
},
"AD426": {
"revision": 1,
"explanation": "A 16 dB power gain is a ratio of $10^(16/10) = 39.8$, so 1 W input becomes about 40 W output.",
"source": "https://50ohm.de/A_verstaerkungsleistung.html",
"confidence": 8
},
"AD427": {
"revision": 1,
"explanation": "For equal impedances, voltage gain in dB is $20 log10(U2/U1)$; $20 log10(4 mV / 1 mV) = 20 log10(4) = 12 dB$.",
"source": "https://50ohm.de/A_verstaerkungsleistung.html",
"confidence": 8
},
"AD428": {
"revision": 1,
"explanation": "Power gain in dB is $10 log10(P2/P1)$; $10 log10(38 W / 2.5 W) = 10 log10(15.2) = 11.8 dB$.",
"source": "https://50ohm.de/A_verstaerkungsleistung.html",
"confidence": 8
},
"AD429": {
"revision": 1,
"explanation": "Efficiency is useful RF output divided by DC input: $10 W / 25 W = 0.40$, or 40%.",
"source": "https://50ohm.de/A_verstaerker_wirkungsgrad.html",
"confidence": 8
},
"AD430": {
"revision": 1,
"explanation": "The DC input power is $12.5 V x 16 A = 200 W$; efficiency is $90 W / 200 W = 0.45$, or 45%.",
"source": "https://50ohm.de/A_verstaerker_wirkungsgrad.html",
"confidence": 8
},
"AD431": {
"revision": 1,
"explanation": "Linear amplification scales the input waveform without changing its shape, so the output curve follows the same waveform at a larger amplitude.",
"source": "https://50ohm.de/A_verstaerker_linearverstaerker.html",
"confidence": 8
},
"AD432": {
"revision": 1,
"explanation": "Self-oscillation happens when output energy is coupled back to the input with enough gain and phase to act as feedback, turning the amplifier into an unintended oscillator.",
"source": "https://50ohm.de/A_verstaerker_eigenschwingung.html",
"confidence": 8
},
"AD433": {
"revision": 1,
"explanation": "A microphone amplifier should pass the speech band while attenuating both too-low and too-high audio frequencies, which is exactly a band-pass response.",
"source": "https://50ohm.de/A_slide_a_grundlegende_schaltungen.html",
"confidence": 7
},
"AD501": {
"revision": 1,
"explanation": "A diode followed by an RC load recovers the envelope of an AM signal, so the circuit is an envelope demodulator for AM.",
"source": "https://50ohm.de/EA_demodulator.html",
"confidence": 7
},
"AD502": {
"revision": 1,
"explanation": "At point X the diode has rectified the AM IF waveform but the RC network has not yet fully smoothed it, so the signal follows the positive envelope with RF ripple remaining.",
"source": "https://50ohm.de/EA_demodulator.html",
"confidence": 7
},
"AD503": {
"revision": 1,
"explanation": "In an envelope detector the extra output from the rectified envelope can be filtered into a DC control voltage, which is used as an AGC/regulating voltage.",
"source": "https://50ohm.de/EA_demodulator.html",
"confidence": 7
},
"AD504": {
"revision": 1,
"explanation": "A tuned circuit offset from the IF converts FM frequency deviations into amplitude changes, which a diode detector can then recover as audio; that is a slope discriminator.",
"source": "https://50ohm.de/EA_demodulator.html",
"confidence": 7
},
"AD505": {
"revision": 1,
"explanation": "A PLL can follow the frequency of an FM signal; the VCO control voltage is then proportional to the original modulation, so the block is a PLL FM demodulator.",
"source": "https://50ohm.de/EA_demodulator.html",
"confidence": 7
},
"AD506": {
"revision": 1,
"explanation": "A product detector mixes the SSB signal with a locally regenerated carrier/BFO so the sideband is converted back to audio.",
"source": "https://50ohm.de/EA_demodulator.html",
"confidence": 7
},
"AD507": {
"revision": 1,
"explanation": "The circuit varies the RF carrier amplitude in step with the audio signal, which is the defining operation of an AM modulator.",
"source": "https://50ohm.de/A_modulatoren.html",
"confidence": 7
},
"AD508": {
"revision": 1,
"explanation": "The audio voltage drives a varicap in the oscillator tank circuit; changing capacitance changes oscillator frequency, so the generated signal is FM.",
"source": "https://50ohm.de/A_modulatoren.html",
"confidence": 7
},
"AD509": {
"revision": 1,
"explanation": "For FM the audio amplitude determines frequency deviation; antiparallel diodes and the level control limit and set that deviation, i.e. the FM deviation or hub.",
"source": "https://50ohm.de/A_modulatoren.html",
"confidence": 7
},
"AD510": {
"revision": 1,
"explanation": "A balanced mixer cancels the carrier when adjusted symmetrically; the sum and difference products remain as the two AM sidebands.",
"source": "https://50ohm.de/A_modulatoren.html",
"confidence": 8
},
"AD601": {
"revision": 1,
"explanation": "A VCO is voltage controlled: a control voltage changes a tuning element such as a varicap, and the oscillator frequency follows that voltage.",
"source": "https://50ohm.de/A_oszillator_vco.html",
"confidence": 8
},
"AD602": {
"revision": 1,
"explanation": "TCXO means Temperature Compensated Crystal Oscillator: a crystal oscillator whose circuit compensates temperature effects instead of holding the whole oscillator in an oven.",
"source": "https://50ohm.de/A_oszillator_tcxo_ocxo.html",
"confidence": 8
},
"AD603": {
"revision": 1,
"explanation": "The abbreviation TCXO expands to Temperature Compensated Crystal Oscillator, i.e. a temperature-compensated crystal oscillator.",
"source": "https://50ohm.de/A_oszillator_tcxo_ocxo.html",
"confidence": 8
},
"AD604": {
"revision": 1,
"explanation": "At 3 cm, small reference errors are multiplied into large RF errors; SSB/SDR operation therefore needs a stable reference, and TCXO is the stable choice among the listed options.",
"source": "https://50ohm.de/A_oszillator_tcxo_ocxo.html",
"confidence": 8
},
"AD605": {
"revision": 1,
"explanation": "An OCXO keeps the crystal oscillator at a controlled oven temperature, so it is more stable than a plain XO, a TCXO, or a VCO.",
"source": "https://50ohm.de/A_oszillator_tcxo_ocxo.html",
"confidence": 8
},
"AD606": {
"revision": 1,
"explanation": "A GPSDO combines a stable local oscillator for short-term stability with a GPS-derived external reference for long-term correction.",
"source": "https://50ohm.de/A_oszillator_gpsdo.html",
"confidence": 8
},
"AD607": {
"revision": 1,
"explanation": "A VFO's frequency depends partly on its operating voltage; stabilized DC prevents supply changes from pulling the oscillator frequency.",
"source": "https://50ohm.de/A_oszillator_spannungsstabilitaet.html",
"confidence": 8
},
"AD608": {
"revision": 1,
"explanation": "The VFO needs voltage-stabilized DC because oscillator frequency can shift when the supply voltage changes.",
"source": "https://50ohm.de/A_oszillator_spannungsstabilitaet.html",
"confidence": 8
},
"AD609": {
"revision": 1,
"explanation": "CW keying can momentarily change oscillator supply voltage; if the oscillator frequency jumps with those voltage changes, the note sounds like chirp.",
"source": "https://50ohm.de/A_oszillator_spannungsstabilitaet.html",
"confidence": 8
},
"AD610": {
"revision": 1,
"explanation": "A buffer stage isolates the oscillator from following stages, so load changes cannot easily pull the oscillator frequency.",
"source": "https://50ohm.de/EA_oszillator_schaltungen.html",
"confidence": 8
},
"AD611": {
"revision": 1,
"explanation": "Unwanted RF feedback into a VFO changes the conditions in the oscillator circuit, which can pull or modulate the generated frequency.",
"source": "https://50ohm.de/A_oszillator_vco.html",
"confidence": 8
},
"AD612": {
"revision": 1,
"explanation": "PA current and RF can disturb a shared supply; filtering and decoupling the VFO supply keeps those disturbances from pulling the oscillator.",
"source": "https://50ohm.de/A_oszillator_spannungsstabilitaet.html",
"confidence": 8
},
"AD613": {
"revision": 1,
"explanation": "Sustained oscillation needs positive feedback at the oscillation frequency: the returned signal must be in phase and at least as large as the signal it reinforces.",
"source": "https://50ohm.de/EA_oszillator_schaltungen.html",
"confidence": 8
},
"AD614": {
"revision": 1,
"explanation": "The LC resonator and capacitive divider form a Colpitts-style three-point oscillator, with the capacitive divider providing the feedback path.",
"source": "https://50ohm.de/EA_oszillator_schaltungen.html",
"confidence": 7
},
"AD615": {
"revision": 1,
"explanation": "The output should be taken at the low-impedance buffered point so the load disturbs the resonant circuit as little as possible; in the drawing that is point D.",
"source": "https://50ohm.de/EA_oszillator_schaltungen.html",
"confidence": 7
},
"AD616": {
"revision": 1,
"explanation": "C1 and C2 form the capacitive voltage divider of the Colpitts oscillator; a fraction of the output is fed back to sustain oscillation.",
"source": "https://50ohm.de/EA_oszillator_schaltungen.html",
"confidence": 7
},
"AD617": {
"revision": 1,
"explanation": "The transistor is used in collector configuration and the crystal sets the oscillation frequency; this circuit is a capacitively fed crystal oscillator on the crystal's fundamental frequency.",
"source": "https://50ohm.de/EA_oszillator_schaltungen.html",
"confidence": 7
},
"AD618": {
"revision": 1,
"explanation": "Point 3 is part of the frequency-determining resonant network; probe capacitance loads that point and therefore shifts the oscillator frequency.",
"source": "https://50ohm.de/EA_oszillator_schaltungen.html",
"confidence": 7
},
"AD619": {
"revision": 1,
"explanation": "The oscillator should be measured at the buffered output point, because probing the resonant circuit directly would add capacitance and detune it; in the drawing that is point 4.",
"source": "https://50ohm.de/EA_oszillator_schaltungen.html",
"confidence": 7
},
"AD620": {
"revision": 1,
"explanation": "The block diagram uses a clock, digital address/phase generation, a sine lookup table, and a D/A converter to synthesize the output, which is direct digital synthesis.",
"source": "https://50ohm.de/A_oszillator_dds.html",
"confidence": 7
},
"AD701": {
"revision": 1,
"explanation": "A basic PLL compares phase, filters the phase-detector output into a control voltage, and uses that voltage to steer a VCO.",
"source": "https://50ohm.de/A_oszillator_pll.html",
"confidence": 8
},
"AD702": {
"revision": 1,
"explanation": "In lock, the phase detector sees equal reference and divided-VCO frequencies, so the signals at the two detector inputs A and B have the same frequency.",
"source": "https://50ohm.de/A_oszillator_pll.html",
"confidence": 7
},
"AD703": {
"revision": 1,
"explanation": "In this integer-N PLL, the smallest output step equals the reference frequency at the phase detector, so a 12.5 kHz channel spacing requires 12.5 kHz at point A.",
"source": "https://50ohm.de/A_oszillator_pll.html",
"confidence": 7
},
"AD704": {
"revision": 1,
"explanation": "The divider ratio is output frequency divided by the 12.5 kHz reference: 12.000 MHz / 12.5 kHz = 960 and 14.000 MHz / 12.5 kHz = 1120.",
"source": "https://50ohm.de/A_oszillator_pll.html",
"confidence": 7
},
"AD705": {
"revision": 1,
"explanation": "A synthesizer locks its output to the reference oscillator, so long-term accuracy and stability mainly follow the quartz reference, not the VCO or dividers.",
"source": "https://50ohm.de/A_oszillator_pll.html",
"confidence": 8
},
"AD801": {
"revision": 1,
"explanation": "The drawing is a resistive pad: only resistors are arranged between input and output to reduce signal level while maintaining impedance.",
"source": "https://50ohm.de/A_daempfungsglieder.html",
"confidence": 7
},
"AD802": {
"revision": 1,
"explanation": "The circuit is a resistive attenuator, not a frequency-selective filter, because its resistor network dissipates part of the RF power as heat.",
"source": "https://50ohm.de/A_daempfungsglieder.html",
"confidence": 7
},
"AD803": {
"revision": 1,
"explanation": "For power ratios, 20 dB corresponds to $10^(20/10) = 100$, so input power is 100 times the load power.",
"source": "https://50ohm.de/A_daempfungsglieder.html",
"confidence": 7
},
"AD804": {
"revision": 1,
"explanation": "For power ratios, 6 dB corresponds approximately to $10^(6/10) = 3.98$, so the practical ratio is 4.",
"source": "https://50ohm.de/A_daempfungsglieder.html",
"confidence": 7
},
"AD805": {
"revision": 1,
"explanation": "A symmetrical attenuator designed for a 50 ohm system presents 50 ohm at its input when its output is terminated with the matching 50 ohm load.",
"source": "https://50ohm.de/A_daempfungsglieder.html",
"confidence": 7
},
"AD806": {
"revision": 1,
"explanation": "A 20 dB attenuator reduces power by a factor of 100, so 100 W input leaves 1 W at the matched load; the remaining 99 W is dissipated as heat in the pad.",
"source": "https://50ohm.de/A_daempfungsglieder.html",
"confidence": 7
},
"AE101": {
"revision": 2,
"explanation": "AFuV defines occupied bandwidth so that the mean power below the lower limit and above the upper limit is 0.5% each of the total mean transmitted power.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__2.html",
"confidence": 10
},
"AE201": {
"revision": 1,
"explanation": "At 100% AM modulation the envelope just reaches zero at its minimum but does not cross or flatten; that is the largest undistorted AM modulation depth.",
"source": "https://50ohm.de/A_am_2.html",
"confidence": 7
},
"AE202": {
"revision": 1,
"explanation": "AM modulation depth is the modulation-envelope amplitude divided by the carrier amplitude; the oscilloscope shows about 3 V modulation on a 6 V carrier, giving 0.5 or 50%.",
"source": "https://50ohm.de/A_am_2.html",
"confidence": 7
},
"AE203": {
"revision": 1,
"explanation": "Overmodulation is AM with modulation depth above 100%; the envelope is driven through zero or pinched off, which causes distortion and sideband splatter.",
"source": "https://50ohm.de/A_am_2.html",
"confidence": 7
},
"AE204": {
"revision": 1,
"explanation": "AM above 100% modulation overdrives the envelope and creates distortion products, so the modulation depth must stay below 100% to avoid splatter.",
"source": "https://50ohm.de/A_am_2.html",
"confidence": 8
},
"AE205": {
"revision": 1,
"explanation": "Overmodulating SSB makes the signal path nonlinear; the resulting distortion spreads energy outside the intended sideband as splatter.",
"source": "https://50ohm.de/A_ssb_3.html",
"confidence": 8
},
"AE206": {
"revision": 1,
"explanation": "A balanced mixer can cancel the carrier while leaving the two sidebands, producing a double-sideband suppressed-carrier signal for SSB generation.",
"source": "https://50ohm.de/A_modulatoren.html",
"confidence": 8
},
"AE207": {
"revision": 1,
"explanation": "A two-tone SSB test produces a characteristic varying RF envelope used to judge linearity and PEP; it is not a constant-envelope FM or simple CW trace.",
"source": "https://50ohm.de/A_ssb_3.html",
"confidence": 7
},
"AE208": {
"revision": 1,
"explanation": "The RF bandwidth of an SSB phone signal is approximately the bandwidth of the applied audio, so limiting speech audio to about 2.7 kHz keeps the SSB signal narrow.",
"source": "https://50ohm.de/A_ssb_3.html",
"confidence": 8
},
"AE209": {
"revision": 1,
"explanation": "SSB phone is normally limited to about 2.7 kHz, so about 3 kHz spacing gives a small guard margin between adjacent SSB signals.",
"source": "https://50ohm.de/A_ssb_3.html",
"confidence": 8
},
"AE210": {
"revision": 1,
"explanation": "An audio dynamic compressor reduces the difference between loud and quiet speech parts, so the modulation has a smaller dynamic range.",
"source": "https://50ohm.de/A_ssb_3.html",
"confidence": 8
},
"AE211": {
"revision": 1,
"explanation": "By lifting quieter speech components and reducing dynamic range, compression raises the average SSB output power without requiring higher peaks when set correctly.",
"source": "https://50ohm.de/A_ssb_3.html",
"confidence": 8
},
"AE212": {
"revision": 1,
"explanation": "Too much compression overprocesses the speech and can drive distortion/splatter, so the received audio becomes less intelligible rather than clearer.",
"source": "https://50ohm.de/A_ssb_3.html",
"confidence": 8
},
"AE213": {
"revision": 1,
"explanation": "An equalizer shapes the microphone audio spectrum, letting the transmitter emphasize or reduce frequency ranges to suit the operator's voice.",
"source": "https://50ohm.de/A_ssb_3.html",
"confidence": 8
},
"AE214": {
"revision": 1,
"explanation": "Amplitude changes that are slower and less abrupt occupy less spectrum; the shown signal with the gentlest amplitude variation therefore has the smallest bandwidth.",
"source": "https://50ohm.de/NEA_symbolumschaltung_bandbreite.html",
"confidence": 7
},
"AE301": {
"revision": 1,
"explanation": "In FM, the modulating signal frequency sets how often the RF carrier frequency is moved back and forth; the modulation amplitude sets how far it moves.",
"source": "https://50ohm.de/A_fm_3.html",
"confidence": 8
},
"AE302": {
"revision": 1,
"explanation": "Impulse noise mainly changes amplitude; FM carries the information in frequency deviation, so amplitude disturbances have less effect than with AM or SSB.",
"source": "https://50ohm.de/A_fm_3.html",
"confidence": 8
},
"AE303": {
"revision": 1,
"explanation": "A varicap changes capacitance with the applied audio/control voltage; in an oscillator tank this shifts the oscillator frequency, producing FM.",
"source": "https://50ohm.de/A_fm_3.html",
"confidence": 8
},
"AE304": {
"revision": 1,
"explanation": "Carson's rule shows FM bandwidth increases with both deviation and the highest modulation frequency, so too high an audio frequency makes the RF bandwidth too large.",
"source": "https://50ohm.de/A_fm_3.html",
"confidence": 8
},
"AE305": {
"revision": 1,
"explanation": "For FM speech, larger deviation represents a larger audio amplitude after demodulation, so the received audio becomes louder.",
"source": "https://50ohm.de/A_fm_3.html",
"confidence": 8
},
"AE306": {
"revision": 1,
"explanation": "Excessive FM deviation widens the transmitted spectrum, so the signal can spill into adjacent channels and cause interference.",
"source": "https://50ohm.de/A_fm_3.html",
"confidence": 8
},
"AE307": {
"revision": 1,
"explanation": "Stronger FM modulator drive increases deviation; higher deviation increases the occupied RF bandwidth.",
"source": "https://50ohm.de/A_fm_3.html",
"confidence": 8
},
"AE308": {
"revision": 1,
"explanation": "Carson's rule gives $B = 2 x (deviation + highest modulation frequency)$, so $2 x (2.5 kHz + 2.7 kHz) = 10.4 kHz$.",
"source": "https://50ohm.de/A_fm_3.html",
"confidence": 8
},
"AE309": {
"revision": 1,
"explanation": "Using Carson's rule, $B = 2 x (1.8 kHz + 2.0 kHz) = 7.6 kHz$; the 145 MHz carrier frequency does not enter this bandwidth estimate.",
"source": "https://50ohm.de/A_fm_3.html",
"confidence": 8
},
"AE310": {
"revision": 1,
"explanation": "Narrowband FM in a 12.5 kHz channel uses a typical peak deviation of about 2.5 kHz, leaving room for modulation sidebands and channel spacing.",
"source": "https://50ohm.de/A_fm_3.html",
"confidence": 8
},
"AE311": {
"revision": 1,
"explanation": "Rearrange Carson's rule: $f_mod = B/2 - deviation = 10 kHz/2 - 2.5 kHz = 2.5 kHz$.",
"source": "https://50ohm.de/A_fm_3.html",
"confidence": 8
},
"AE312": {
"revision": 1,
"explanation": "Rearrange Carson's rule: deviation $= B/2 - f_mod = 10 kHz/2 - 2.7 kHz = 2.3 kHz$.",
"source": "https://50ohm.de/A_fm_3.html",
"confidence": 8
},
"AE313": {
"revision": 1,
"explanation": "PM means phase modulation: the information signal changes the phase of the carrier rather than its amplitude or polarization.",
"source": "https://50ohm.de/EA_pm.html",
"confidence": 8
},
"AE401": {
"revision": 1,
"explanation": "PSK keeps the carrier amplitude essentially constant but introduces abrupt phase changes; the correct trace is the one where the sine wave jumps phase rather than changing amplitude or frequency smoothly.",
"source": "https://50ohm.de/NEA_psk.html",
"confidence": 7
},
"AE402": {
"revision": 1,
"explanation": "BPSK has two phase states, so each symbol carries one bit; QPSK has four phase states, so each symbol carries two bits.",
"source": "https://50ohm.de/A_mehrwertige_verfahren.html",
"confidence": 8
},
"AE403": {
"revision": 1,
"explanation": "QAM maps data onto combinations of carrier amplitude and carrier phase, giving more possible symbols than amplitude-only modulation.",
"source": "https://50ohm.de/A_qam.html",
"confidence": 8
},
"AE404": {
"revision": 1,
"explanation": "QAM is commonly generated by amplitude-modulating two carriers that are 90 degrees apart, then adding them as I and Q components.",
"source": "https://50ohm.de/EA_iq_verfahren.html",
"confidence": 8
},
"AE405": {
"revision": 1,
"explanation": "With two symbol frequencies, each symbol represents one bit, so 45.45 baud corresponds directly to 45.45 bit/s.",
"source": "https://50ohm.de/A_mehrwertige_verfahren.html",
"confidence": 8
},
"AE406": {
"revision": 1,
"explanation": "Four symbol frequencies encode two bits per symbol; data rate is symbol rate times bits per symbol, so $23.4 x 2 = 46.8 bit/s$.",
"source": "https://50ohm.de/A_mehrwertige_verfahren.html",
"confidence": 8
},
"AE407": {
"revision": 1,
"explanation": "Synchronization means sender and receiver agree on timing, so the receiver knows where symbols or frames begin and can decode them correctly.",
"source": "https://50ohm.de/NEA_synchronisation.html",
"confidence": 8
},
"AE408": {
"revision": 1,
"explanation": "Source coding reduces the original message data, for example by removing redundancy or irrelevant information through compression.",
"source": "https://50ohm.de/NEA_quellencodierung.html",
"confidence": 8
},
"AE409": {
"revision": 1,
"explanation": "Channel coding deliberately adds redundancy before transmission so the receiver can detect or correct errors caused by the channel.",
"source": "https://50ohm.de/NEA_kanalcodierung.html",
"confidence": 8
},
"AE410": {
"revision": 1,
"explanation": "CRC is a checksum-like error detection method for data blocks; it computes redundant check information from the block contents.",
"source": "https://50ohm.de/NEA_fehlererkennung.html",
"confidence": 8
},
"AE411": {
"revision": 1,
"explanation": "A single parity bit flips its check result when an odd number of bits is wrong; even numbers of bit errors preserve the parity and can pass undetected.",
"source": "https://50ohm.de/NEA_fehlererkennung.html",
"confidence": 8
},
"AE412": {
"revision": 1,
"explanation": "A passing parity check only proves the parity is unchanged; that can mean no error or an even number of bit errors including the parity bit.",
"source": "https://50ohm.de/NEA_fehlererkennung.html",
"confidence": 8
},
"AE413": {
"revision": 1,
"explanation": "Without FEC the receiver cannot reconstruct corrupted packet contents from redundancy, so correction requires requesting or receiving the packet again.",
"source": "https://50ohm.de/EA_fehlerkorrektur.html",
"confidence": 8
},
"AE414": {
"revision": 1,
"explanation": "Forward error correction needs redundant information in the transmitted data, so the receiver has enough extra checks to locate and correct errors.",
"source": "https://50ohm.de/EA_fehlerkorrektur.html",
"confidence": 8
},
"AE415": {
"revision": 1,
"explanation": "Faster symbol changes mean faster amplitude, frequency, or phase transitions, and faster transitions require a wider spectrum.",
"source": "https://50ohm.de/NEA_symbolumschaltung_bandbreite.html",
"confidence": 8
},
"AE416": {
"revision": 1,
"explanation": "Shannon-Hartley gives the theoretical maximum error-free data rate for a channel from its bandwidth and signal-to-noise ratio.",
"source": "https://50ohm.de/A_shannon_hartley_gesetzt.html",
"confidence": 8
},
"AE417": {
"revision": 1,
"explanation": "At 0 dB SNR the linear SNR is 1, so $C = B x log2(1 + 1) = B$; 2.7 kHz therefore gives about 2.7 kbit/s.",
"source": "https://50ohm.de/A_shannon_hartley_gesetzt.html",
"confidence": 8
},
"AE418": {
"revision": 1,
"explanation": "At 0 dB SNR, Shannon-Hartley reduces to capacity approximately equal to bandwidth in bit/s, so 10 MHz gives about 10 Mbit/s.",
"source": "https://50ohm.de/A_shannon_hartley_gesetzt.html",
"confidence": 8
},
"AE419": {
"revision": 1,
"explanation": "30 dB SNR is a linear ratio of 1000, so capacity is $10 MHz x log2(1001)$, about $10 MHz x 10 = 100 Mbit/s$.",
"source": "https://50ohm.de/A_shannon_hartley_gesetzt.html",
"confidence": 8
},
"AE420": {
"revision": 1,
"explanation": "-20 dB SNR is a linear ratio of 0.01; $2700 x log2(1.01)$ is about 39 bit/s, so transmission is possible but very slow.",
"source": "https://50ohm.de/A_shannon_hartley_gesetzt.html",
"confidence": 8
},
"AE421": {
"revision": 1,
"explanation": "OFDM spreads data across many narrow subcarriers; a narrowband interferer damages only some carriers, and redundancy can recover the lost information.",
"source": "https://50ohm.de/EA_ofdm.html",
"confidence": 8
},
"AE422": {
"revision": 1,
"explanation": "OFDM uses longer symbols on many subcarriers, so delayed copies from multipath overlap less destructively and can be handled better with redundant coding.",
"source": "https://50ohm.de/EA_ofdm.html",
"confidence": 8
},
"AF101": {
"revision": 1,
"explanation": "Increasing power from 25 W to 100 W is a factor of 4, or +6 dB; one S-unit corresponds to 6 dB.",
"source": "https://50ohm.de/NEA_s_meter.html",
"confidence": 8
},
"AF102": {
"revision": 1,
"explanation": "Increasing power from 100 W to 400 W is again a factor of 4, which is +6 dB, equal to one S-unit.",
"source": "https://50ohm.de/NEA_s_meter.html",
"confidence": 8
},
"AF103": {
"revision": 1,
"explanation": "A tenfold power increase is +10 dB. From S8, +6 dB reaches S9 and the remaining +4 dB gives S9+4 dB.",
"source": "https://50ohm.de/NEA_s_meter.html",
"confidence": 8
},
"AF104": {
"revision": 1,
"explanation": "S7 to S9 is two S-units, or 12 dB; S9+8 dB makes the total increase 20 dB, which is a 100-fold power ratio.",
"source": "https://50ohm.de/NEA_s_meter.html",
"confidence": 8
},
"AF105": {
"revision": 1,
"explanation": "One S-unit lower is -6 dB in voltage, i.e. half the input voltage; half of 50 microvolt is 25 microvolt.",
"source": "https://50ohm.de/NEA_s_meter.html",
"confidence": 8
},
"AF106": {
"revision": 1,
"explanation": "In a simple superhet, the wanted signal and its image are on opposite sides of the local oscillator by one IF each, so their separation is twice the IF.",
"source": "https://50ohm.de/EA_spiegelfrequenzen.html",
"confidence": 8
},
"AF107": {
"revision": 1,
"explanation": "The IF is $24.94 MHz - 14.24 MHz = 10.70 MHz$; the image on the other side of the oscillator is $24.94 MHz + 10.70 MHz = 35.64 MHz$.",
"source": "https://50ohm.de/EA_spiegelfrequenzen.html",
"confidence": 7
},
"AF108": {
"revision": 1,
"explanation": "With high-side injection the oscillator is $28.5 MHz + 10.7 MHz = 39.2 MHz$; the image is another IF above that, $39.2 MHz + 10.7 MHz = 49.9 MHz$.",
"source": "https://50ohm.de/EA_spiegelfrequenzen.html",
"confidence": 7
},
"AF109": {
"revision": 1,
"explanation": "A very high first IF moves the image by twice that IF, placing the image far away from the wanted HF band where RF filtering can reject it more easily.",
"source": "https://50ohm.de/A_ueberlagerungsempfaenger_einfachsuper_2.html",
"confidence": 8
},
"AF110": {
"revision": 1,
"explanation": "Image frequency separation is twice the IF, so the IF value mainly determines how far the image is from the wanted frequency and how easily it can be filtered.",
"source": "https://50ohm.de/EA_spiegelfrequenzen.html",
"confidence": 8
},
"AF111": {
"revision": 1,
"explanation": "A high first IF gives a large spacing between wanted and image frequencies, improving image-frequency rejection before the mixer.",
"source": "https://50ohm.de/A_doppelueberlagerungsempfaenger_doppelsuper.html",
"confidence": 8
},
"AF112": {
"revision": 1,
"explanation": "In a double superhet, the high first IF is chosen mainly for image rejection, while later lower IF stages can provide selectivity.",
"source": "https://50ohm.de/A_doppelueberlagerungsempfaenger_doppelsuper.html",
"confidence": 8
},
"AF113": {
"revision": 1,
"explanation": "A low second IF allows narrow, high-selectivity filters, so it is useful for good adjacent-signal separation.",
"source": "https://50ohm.de/A_doppelueberlagerungsempfaenger_doppelsuper.html",
"confidence": 8
},
"AF114": {
"revision": 1,
"explanation": "The high first IF helps image rejection; after roofing-filter preselection, conversion to a lower second IF makes narrow filtering and selectivity easier.",
"source": "https://50ohm.de/A_doppelueberlagerungsempfaenger_doppelsuper.html",
"confidence": 8
},
"AF115": {
"revision": 1,
"explanation": "Near selectivity is the ability to separate nearby signals, and that is set by the receiver's IF filters rather than by RF gain stages.",
"source": "https://50ohm.de/A_doppelueberlagerungsempfaenger_doppelsuper.html",
"confidence": 8
},
"AF116": {
"revision": 1,
"explanation": "The first IF filter must not cut off any intended mode, so its bandwidth must be at least as wide as the widest receive mode the receiver is meant to handle.",
"source": "https://50ohm.de/A_doppelueberlagerungsempfaenger_doppelsuper.html",
"confidence": 8
},
"AF117": {
"revision": 1,
"explanation": "The first mixer is driven by the tunable VFO, the second conversion by a fixed crystal oscillator, and the final product detector needs the BFO to recover SSB/CW audio.",
"source": "https://50ohm.de/A_doppelueberlagerungsempfaenger_doppelsuper.html",
"confidence": 7
},
"AF118": {
"revision": 1,
"explanation": "High-side first conversion needs $21.1 MHz + 9 MHz = 30.1 MHz$ for the VFO; low-side conversion from 9 MHz to 460 kHz needs $9 MHz - 0.460 MHz = 8.54 MHz$ for the CO.",
"source": "https://50ohm.de/A_doppelueberlagerungsempfaenger_doppelsuper.html",
"confidence": 7
},
"AF119": {
"revision": 1,
"explanation": "With both oscillators above their input signals, the VFO is $28.00 MHz + 10.70 MHz = 38.70 MHz$ and the second oscillator is $10.70 MHz + 0.460 MHz = 11.16 MHz$.",
"source": "https://50ohm.de/A_doppelueberlagerungsempfaenger_doppelsuper.html",
"confidence": 7
},
"AF120": {
"revision": 1,
"explanation": "The chain can mix $3.65 MHz + 46.35 MHz$ to a 50 MHz first IF, then $50 MHz - 41 MHz$ to 9 MHz, then $9.455 MHz - 9 MHz$ to 455 kHz.",
"source": "https://50ohm.de/A_doppelueberlagerungsempfaenger_doppelsuper.html",
"confidence": 7
},
"AF201": {
"revision": 1,
"explanation": "The wanted signal and image produce the same IF on opposite sides of the local oscillator, so their frequency spacing is twice the IF.",
"source": "https://50ohm.de/A_spiegelfrequenzen.html",
"confidence": 7
},
"AF202": {
"revision": 1,
"explanation": "The IF is $145.6 MHz - 134.9 MHz = 10.7 MHz$; the image is the other signal 10.7 MHz from the oscillator, $134.9 MHz - 10.7 MHz = 124.2 MHz$.",
"source": "https://50ohm.de/A_spiegelfrequenzen.html",
"confidence": 7
},
"AF203": {
"revision": 1,
"explanation": "The image is mirrored around the oscillator frequency: $2 x 39 MHz - 28.3 MHz = 49.7 MHz$.",
"source": "https://50ohm.de/A_spiegelfrequenzen.html",
"confidence": 8
},
"AF204": {
"revision": 1,
"explanation": "Image rejection must happen before the mixer, because the wanted signal and image become the same IF after mixing; therefore RF preselection determines image attenuation.",
"source": "https://50ohm.de/A_spiegelfrequenzen.html",
"confidence": 8
},
"AF205": {
"revision": 1,
"explanation": "Receiver selectivity is set by the IF filters, because nearby signals are separated after conversion to the fixed intermediate frequency.",
"source": "https://50ohm.de/A_slide_a_empfaenger.html",
"confidence": 8
},
"AF206": {
"revision": 1,
"explanation": "Typical receiver IF bandwidths match the mode: about 2.7 kHz for SSB speech, about 500 Hz for narrow RTTY/CW-like signals, and about 12 kHz for FM speech.",
"source": "https://50ohm.de/A_slide_a_empfaenger.html",
"confidence": 8
},
"AF207": {
"revision": 1,
"explanation": "The shown narrow passband is around the audio bandwidth used for SSB, much narrower than FM and not shaped for wide digital OFDM.",
"source": "https://50ohm.de/A_slide_a_empfaenger.html",
"confidence": 7
},
"AF208": {
"revision": 1,
"explanation": "Crystal filters can have very high Q and steep skirts, so they are best suited for narrow IF bandwidths at a given center frequency.",
"source": "https://50ohm.de/A_slide_a_empfaenger.html",
"confidence": 8
},
"AF209": {
"revision": 1,
"explanation": "In a double superhet, the first two conversion blocks are mixers, and the final block before audio is a product detector for SSB/CW demodulation.",
"source": "https://50ohm.de/A_doppelueberlagerungsempfaenger_doppelsuper.html",
"confidence": 7
},
"AF210": {
"revision": 1,
"explanation": "For a 50 MHz first IF and a 3 to 30 MHz receive range, the VFO can use either difference mixing $50 - f_rx$ = 47 to 20 MHz or sum mixing $50 + f_rx$ = 53 to 80 MHz.",
"source": "https://50ohm.de/A_doppelueberlagerungsempfaenger_doppelsuper.html",
"confidence": 7
},
"AF211": {
"revision": 1,
"explanation": "For CW, the BFO is offset from the last IF by an audible tone frequency; about 800 Hz gives a comfortable received beat note.",
"source": "https://50ohm.de/A_slide_a_empfaenger.html",
"confidence": 8
},
"AF212": {
"revision": 1,
"explanation": "A mixer must be nonlinear so it creates sum and difference products from the input and local oscillator frequencies.",
"source": "https://50ohm.de/A_mischer_2.html",
"confidence": 8
},
"AF213": {
"revision": 1,
"explanation": "A balanced mixer cancels some unwanted components such as carrier/oscillator feedthrough, so fewer unwanted output signals remain than with simple unbalanced mixers.",
"source": "https://50ohm.de/A_mischer_2.html",
"confidence": 8
},
"AF214": {
"revision": 1,
"explanation": "A balanced ring mixer has strong symmetry, which suppresses unwanted feedthrough and many unwanted mixer products better than simple unbalanced mixer circuits.",
"source": "https://50ohm.de/A_mischer_2.html",
"confidence": 8
},
"AF215": {
"revision": 1,
"explanation": "Even a temperature-compensated VFO can drift if heated unevenly, so it should be thermally isolated from power stages and other heat sources.",
"source": "https://50ohm.de/A_oszillator_tcxo_ocxo.html",
"confidence": 8
},
"AF216": {
"revision": 1,
"explanation": "An SSB BFO must be frequency-stable because its frequency defines the reinserted carrier position; a crystal-controlled oscillator is the stable choice.",
"source": "https://50ohm.de/A_slide_a_empfaenger.html",
"confidence": 8
},
"AF217": {
"revision": 1,
"explanation": "Two signals in a nonlinear receiver stage generate sum, difference, and higher-order products; that phenomenon is intermodulation.",
"source": "https://50ohm.de/A_intermodulation_kreuzmodulation.html",
"confidence": 8
},
"AF218": {
"revision": 1,
"explanation": "Intermodulation is caused by nonlinearity: strong input signals push the RF stage out of its linear range and create extra frequency products.",
"source": "https://50ohm.de/A_intermodulation_kreuzmodulation.html",
"confidence": 8
},
"AF219": {
"revision": 1,
"explanation": "Cross modulation occurs when a strong unwanted signal affects the receiver stage and transfers its modulation onto the desired signal.",
"source": "https://50ohm.de/A_intermodulation_kreuzmodulation.html",
"confidence": 8
},
"AF220": {
"revision": 1,
"explanation": "An input attenuator reduces the level of all incoming strong signals, keeping the receiver front end more linear and reducing intermodulation and cross modulation.",
"source": "https://50ohm.de/A_intermodulation_kreuzmodulation.html",
"confidence": 8
},
"AF221": {
"revision": 1,
"explanation": "IP3 is a measure of third-order intermodulation behavior, so it indicates how well the receiver handles large signals without generating distortion products.",
"source": "https://50ohm.de/A_intermodulation_kreuzmodulation.html",
"confidence": 8
},
"AF222": {
"revision": 1,
"explanation": "A strong nearby RF signal can overload or desensitize receiver stages, producing intermodulation or cross modulation that degrades the wanted signal.",
"source": "https://50ohm.de/A_intermodulation_kreuzmodulation.html",
"confidence": 8
},
"AF223": {
"revision": 1,
"explanation": "A notch or trap tuned to the unwanted signal at the receiver input can reject that interferer before it reaches the sensitive front end.",
"source": "https://50ohm.de/A_intermodulation_kreuzmodulation.html",
"confidence": 7
},
"AF224": {
"revision": 1,
"explanation": "AGC keeps receiver output level more constant; for strong input signals it reduces gain in receiver amplifier stages.",
"source": "https://50ohm.de/A_slide_a_empfaenger.html",
"confidence": 8
},
"AF225": {
"revision": 1,
"explanation": "Squelch decides whether useful modulation or carrier/noise is present by evaluating IF or audio-derived signals, then mutes or unmutes the receiver audio.",
"source": "https://50ohm.de/A_slide_a_empfaenger.html",
"confidence": 8
},
"AF226": {
"revision": 1,
"explanation": "In FM, information is in frequency deviation, so a limiter removes amplitude variations and suppresses AM noise before demodulation.",
"source": "https://50ohm.de/A_slide_a_empfaenger.html",
"confidence": 8
},
"AF227": {
"revision": 1,
"explanation": "SNR is the ratio of wanted signal power to noise power; a higher SNR means the wanted signal stands out more clearly from noise.",
"source": "https://50ohm.de/A_slide_a_empfaenger.html",
"confidence": 8
},
"AF228": {
"revision": 1,
"explanation": "Noise figure in dB states how much the amplifier worsens SNR; 1.8 dB means the output SNR is 1.8 dB lower than the input SNR.",
"source": "https://50ohm.de/A_slide_a_empfaenger.html",
"confidence": 8
},
"AF229": {
"revision": 1,
"explanation": "A noise factor of 2 corresponds to $10 log10(2) = 3 dB$, meaning the amplifier degrades the signal-to-noise ratio by 3 dB.",
"source": "https://50ohm.de/A_slide_a_empfaenger.html",
"confidence": 8
},
"AF230": {
"revision": 1,
"explanation": "The LNB amplifies the weak microwave signal at the antenna and converts it to a lower IF, so the long coax no longer carries the original 10 GHz signal with its high cable loss.",
"source": "https://50ohm.de/A_low_noise_block.html",
"confidence": 7
},
"AF231": {
"revision": 1,
"explanation": "Satellite LNBs commonly use different supply voltages to select polarization; raising the Bias-T supply to 18 V commands a polarization change.",
"source": "https://50ohm.de/A_low_noise_block.html",
"confidence": 7
},
"AF301": {
"revision": 1,
"explanation": "A mixer can add the 5.3 MHz signal and a 9 MHz oscillator to produce 14.3 MHz; a bandfilter then selects that desired product.",
"source": "https://50ohm.de/A_transverter_2.html",
"confidence": 8
},
"AF302": {
"revision": 1,
"explanation": "A balanced mixer/modulator suppresses the carrier by symmetry while leaving the two sidebands, producing DSB with suppressed carrier.",
"source": "https://50ohm.de/A_modulatoren.html",
"confidence": 8
},
"AF303": {
"revision": 1,
"explanation": "The usual analog SSB chain first creates DSB with a balanced modulator, then a sideband filter passes only one of the two sidebands.",
"source": "https://50ohm.de/A_modulatoren.html",
"confidence": 8
},
"AF304": {
"revision": 1,
"explanation": "Analog SSB generation suppresses the carrier in the balanced modulator and removes the unwanted sideband with a filter.",
"source": "https://50ohm.de/A_modulatoren.html",
"confidence": 8
},
"AF305": {
"revision": 1,
"explanation": "After the balanced modulator has made DSB, the marked filter must be a narrow bandpass, commonly a crystal filter, that selects the desired sideband.",
"source": "https://50ohm.de/A_modulatoren.html",
"confidence": 7
},
"AF306": {
"revision": 1,
"explanation": "The block after the audio amplifier multiplies the audio with the carrier oscillator; in an SSB transmitter that function is the balanced mixer/modulator.",
"source": "https://50ohm.de/A_modulatoren.html",
"confidence": 7
},
"AF307": {
"revision": 1,
"explanation": "The USB carrier frequency is symmetric to the LSB carrier around the 9 MHz filter center: $9.0000 MHz - (9.0015 - 9.0000) MHz = 8.9985 MHz$.",
"source": "https://50ohm.de/A_modulatoren.html",
"confidence": 7
},
"AF308": {
"revision": 1,
"explanation": "The balanced diode modulator cancels the carrier and leaves the modulation sidebands, so it generates AM with suppressed carrier.",
"source": "https://50ohm.de/A_modulatoren.html",
"confidence": 7
},
"AF309": {
"revision": 1,
"explanation": "The balancing network trims amplitude and phase so the carrier components cancel as well as possible in the balanced modulator.",
"source": "https://50ohm.de/A_modulatoren.html",
"confidence": 7
},
"AF310": {
"revision": 1,
"explanation": "The diode is a varicap in the oscillator tank; the audio voltage changes its capacitance, shifting the resonant frequency and producing FM.",
"source": "https://50ohm.de/A_modulatoren.html",
"confidence": 7
},
"AF311": {
"revision": 1,
"explanation": "Analog frequency multiplication deliberately drives a nonlinear stage to create harmonics, then filters out the desired harmonic frequency.",
"source": "https://50ohm.de/A_frequenzvervielfacher_2.html",
"confidence": 8
},
"AF312": {
"revision": 1,
"explanation": "The stage is biased and tuned to use distortion harmonics rather than linear amplification, which identifies it as a frequency multiplier.",
"source": "https://50ohm.de/A_frequenzvervielfacher_2.html",
"confidence": 7
},
"AF313": {
"revision": 1,
"explanation": "Frequency multipliers intentionally generate harmonics, including unwanted ones, so shielding is important to prevent those signals from being radiated.",
"source": "https://50ohm.de/A_frequenzvervielfacher_2.html",
"confidence": 8
},
"AF314": {
"revision": 1,
"explanation": "Only the sequence $12 MHz x 2 x 2 x 3 x 3$ passes through 144 MHz as an intermediate result: 24 MHz, 48 MHz, 144 MHz, then 432 MHz.",
"source": "https://50ohm.de/A_frequenzvervielfacher_2.html",
"confidence": 8
},
"AF401": {
"revision": 1,
"explanation": "HF amplifier efficiency is useful RF output power divided by the DC power taken from the supply.",
"source": "https://50ohm.de/A_verstaerker_wirkungsgrad.html",
"confidence": 8
},
"AF402": {
"revision": 1,
"explanation": "Class C conducts for less than half the RF cycle, making it highly nonlinear and therefore rich in harmonics.",
"source": "https://50ohm.de/A_verstaerker_klasse.html",
"confidence": 8
},
"AF403": {
"revision": 1,
"explanation": "Class C stages and their output networks can contain strong harmonics, so the matching and filtering circuits should be enclosed in a shielded metal housing.",
"source": "https://50ohm.de/NEA_leistungsvertaerker.html",
"confidence": 8
},
"AF404": {
"revision": 1,
"explanation": "An LC output network transforms the PA output impedance to the antenna impedance and, because it is frequency-selective, also attenuates harmonics.",
"source": "https://50ohm.de/NEA_leistungsvertaerker.html",
"confidence": 8
},
"AF405": {
"revision": 1,
"explanation": "A pi output filter acts as an impedance transformer and a low-pass network, so it improves matching while suppressing harmonics.",
"source": "https://50ohm.de/NEA_leistungsvertaerker.html",
"confidence": 8
},
"AF406": {
"revision": 1,
"explanation": "The marked output network is the matching section; it transforms the external load impedance to the impedance the transistor stage needs.",
"source": "https://50ohm.de/NEA_leistungsvertaerker.html",
"confidence": 7
},
"AF407": {
"revision": 1,
"explanation": "The marked input matching parts transform the previous stage's output impedance to the transistor's required input impedance for proper drive.",
"source": "https://50ohm.de/NEA_leistungsvertaerker.html",
"confidence": 7
},
"AF408": {
"revision": 1,
"explanation": "The tuned resonant circuits in the RF signal path make the stage frequency-selective, so it is a selective RF amplifier rather than a broadband or audio amplifier.",
"source": "https://50ohm.de/NEA_leistungsvertaerker.html",
"confidence": 7
},
"AF409": {
"revision": 1,
"explanation": "A tapped resonant circuit can provide impedance transformation, letting the preceding stage drive the tuned amplifier input at a suitable impedance point.",
"source": "https://50ohm.de/NEA_leistungsvertaerker.html",
"confidence": 7
},
"AF410": {
"revision": 1,
"explanation": "C1 and C2 are part of the matching network, setting the impedance transformation between the transistor stage and the connected circuit.",
"source": "https://50ohm.de/NEA_leistungsvertaerker.html",
"confidence": 7
},
"AF411": {
"revision": 1,
"explanation": "The marked supply decoupling path gives RF a low-impedance route to ground, preventing RF from entering the DC supply line.",
"source": "https://50ohm.de/NEA_leistungsvertaerker.html",
"confidence": 7
},
"AF412": {
"revision": 1,
"explanation": "The push-pull transformer-coupled layout is intended for broadband RF amplification rather than a narrow tuned stage, so it is a broadband push-pull amplifier.",
"source": "https://50ohm.de/NEA_leistungsvertaerker.html",
"confidence": 7
},
"AF413": {
"revision": 1,
"explanation": "The two cascaded broadband transformer-coupled stages identify the circuit as a two-stage broadband RF amplifier.",
"source": "https://50ohm.de/NEA_leistungsvertaerker.html",
"confidence": 7
},
"AF414": {
"revision": 1,
"explanation": "The transformer couples stages while transforming the output impedance of one emitter stage to the input impedance of the following emitter stage.",
"source": "https://50ohm.de/NEA_leistungsvertaerker.html",
"confidence": 7
},
"AF415": {
"revision": 1,
"explanation": "Large capacitors are effective at low frequencies but poorer at very high RF; small capacitors keep low impedance at high frequencies, so the parallel pair decouples over a wider range.",
"source": "https://50ohm.de/NEA_leistungsvertaerker.html",
"confidence": 7
},
"AF416": {
"revision": 1,
"explanation": "The resistor damps the transformer winding, reducing excessive Q and helping prevent parasitic oscillations.",
"source": "https://50ohm.de/NEA_leistungsvertaerker.html",
"confidence": 7
},
"AF417": {
"revision": 1,
"explanation": "The transformers provide broadband impedance transformation between the 50 ohm system and the low transistor input and output impedances.",
"source": "https://50ohm.de/NEA_leistungsvertaerker.html",
"confidence": 7
},
"AF418": {
"revision": 1,
"explanation": "An inductor in series with shunt capacitors forms an LC low-pass section: it passes DC/low-frequency supply current but diverts RF to ground.",
"source": "https://50ohm.de/NEA_leistungsvertaerker.html",
"confidence": 7
},
"AF419": {
"revision": 1,
"explanation": "The choke and bypass capacitors form supply-line filtering, reducing RF components on the DC supply line rather than filtering the transmitted RF path itself.",
"source": "https://50ohm.de/NEA_leistungsvertaerker.html",
"confidence": 7
},
"AF420": {
"revision": 1,
"explanation": "Moving R3 toward position 3 lowers the gate bias for both LDMOS devices in the DC equivalent circuit, so both drain currents decrease.",
"source": "https://50ohm.de/NEA_leistungsvertaerker.html",
"confidence": 7
},
"AF421": {
"revision": 1,
"explanation": "For DC bias, the gates draw negligible current and the resistor network acts as a voltage divider; at stop 1 the divider sets the gate-source voltage to 3.5 V.",
"source": "https://50ohm.de/NEA_leistungsvertaerker.html",
"confidence": 7
},
"AF422": {
"revision": 1,
"explanation": "The coils are RF chokes in the supply feeds; they pass DC but present high impedance to RF, keeping RF out of the supply line.",
"source": "https://50ohm.de/NEA_leistungsvertaerker.html",
"confidence": 7
},
"AF423": {
"revision": 1,
"explanation": "Increasing LDMOS quiescent current means raising both gate-bias voltages, so both bias controls are moved toward UBIAS.",
"source": "https://50ohm.de/NEA_leistungsvertaerker.html",
"confidence": 7
},
"AF424": {
"revision": 1,
"explanation": "R4 affects only the bias path for transistor 1 in the shown circuit; moving its wiper toward UBIAS raises that gate bias and drain current, while transistor 2 is unchanged.",
"source": "https://50ohm.de/NEA_leistungsvertaerker.html",
"confidence": 7
},
"AF425": {
"revision": 1,
"explanation": "The resistor must drop $13.5 V - 4 V = 9.5 V$ at 10 mA, so $R = 9.5 V / 0.010 A = 950 ohm$.",
"source": "https://50ohm.de/A_integrierte_schaltkreise.html",
"confidence": 7
},
"AF426": {
"revision": 1,
"explanation": "The bias resistor drops $13.8 V - 4 V = 9.8 V$ at 15 mA; $9.8 V / 0.015 A = 653 ohm$, so the nearest listed standard value is 680 ohm.",
"source": "https://50ohm.de/A_integrierte_schaltkreise.html",
"confidence": 7
},
"AF427": {
"revision": 1,
"explanation": "With a 4 V MMIC drop, the resistor current is $(9 V - 4 V) / 470 ohm = 10.6 mA$; MMIC heat is $4 V x 10.6 mA = 42.6 mW$, about 43 mW.",
"source": "https://50ohm.de/A_integrierte_schaltkreise.html",
"confidence": 7
},
"AF428": {
"revision": 1,
"explanation": "Overall gain in dB is the output level minus the input level in dBm; the diagram's level difference is 48 dB when cable losses are ignored.",
"source": "https://50ohm.de/NEA_leistungsvertaerker.html",
"confidence": 7
},
"AF501": {
"revision": 1,
"explanation": "The converter uses the 9th harmonic of the crystal oscillator and maps the 436 to 440 MHz range to 28 to 30 MHz, so $f_Q = (f_rx - f_IF) / 9$ gives 45.333 MHz and 45.556 MHz.",
"source": "https://50ohm.de/A_transverter_2.html",
"confidence": 7
},
"AF502": {
"revision": 1,
"explanation": "For the lower 70 cm segment, the same conversion maps 430 to 434 MHz down to 28 to 30 MHz using the 9th harmonic, so $(430 - 28) / 9 = 44.667 MHz$ and $(434 - 30) / 9 = 44.889 MHz$.",
"source": "https://50ohm.de/A_transverter_2.html",
"confidence": 7
},
"BA101": {
"revision": 2,
"explanation": "DD4UQ spells D as Delta, U as Uniform and Q as Quebec; the traps are country-style words such as Denmark, Uruguay and Queen, which are not the ITU code words.",
"source": "https://life.itu.int/radioclub/rr/ap14.pdf",
"confidence": 9
},
"BA102": {
"revision": 2,
"explanation": "DK1KC uses Delta for D, Kilo for K and Charlie for C; Kilowatt, Denmark and Caesar are distractors, not ITU spelling-alphabet words.",
"source": "https://life.itu.int/radioclub/rr/ap14.pdf",
"confidence": 9
},
"BA103": {
"revision": 2,
"explanation": "DK5WP maps to Delta Kilo 5 Whiskey Papa; Kilowatt, William and Paris are common-looking substitutes but not the ITU words for K, W and P.",
"source": "https://life.itu.int/radioclub/rr/ap14.pdf",
"confidence": 9
},
"BA104": {
"revision": 2,
"explanation": "DL1FLO maps D/L/F/L/O to Delta, Lima, Foxtrot, Lima, Oscar; London, Florida and Oslo are distractors rather than ITU code words.",
"source": "https://life.itu.int/radioclub/rr/ap14.pdf",
"confidence": 9
},
"BA105": {
"revision": 2,
"explanation": "DL4YBZ uses Yankee, Bravo and Zulu for Y, B and Z; Ypsilon, Baker and Zebra are the non-ITU traps in the answer choices.",
"source": "https://life.itu.int/radioclub/rr/ap14.pdf",
"confidence": 9
},
"BA106": {
"revision": 2,
"explanation": "DM4EAX spells M as Mike, E as Echo, A as Alfa and X as X-ray; Madagascar, Ecuador and Amerika are distractors outside the ITU alphabet.",
"source": "https://life.itu.int/radioclub/rr/ap14.pdf",
"confidence": 9
},
"BA107": {
"revision": 2,
"explanation": "DN9RO/p uses Romeo and Oscar for R and O, while '/' is spoken as Stroke before the portable suffix; Radio, Oslo and Nordpol are distractors.",
"source": "https://life.itu.int/radioclub/rr/ap14.pdf",
"confidence": 9
},
"BA108": {
"revision": 2,
"explanation": "DN9STV maps S/T/V to Sierra, Tango and Victor; Santiago, Texas and Vulcano are plausible-sounding but not ITU code words.",
"source": "https://life.itu.int/radioclub/rr/ap14.pdf",
"confidence": 9
},
"BA109": {
"revision": 2,
"explanation": "DO9XJZ uses X-ray, Juliett and Zulu for X, J and Z; Xavier, Japan and Zebra are the distractor words.",
"source": "https://life.itu.int/radioclub/rr/ap14.pdf",
"confidence": 9
},
"BA110": {
"revision": 2,
"explanation": "IG9/DL4HR starts India Golf and uses Stroke for '/', with Hotel and Romeo at the end; Italy, Guatemala and Honolulu are distractors.",
"source": "https://life.itu.int/radioclub/rr/ap14.pdf",
"confidence": 9
},
"BB101": {
"revision": 1,
"explanation": "Abbreviations and Q groups compress common operating messages, so slow text modes carry more meaning per character and keep contacts concise.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BB102": {
"revision": 1,
"explanation": "CQ is the standard open invitation to any station, not a call to one named station.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BB103": {
"revision": 1,
"explanation": "DX is operating shorthand for a distant station or long-distance contact; the distance threshold depends on band and propagation.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BB104": {
"revision": 1,
"explanation": "On VHF/UHF, normal local coverage is limited, so DX means stations well beyond local range, typically more than a few hundred kilometres away.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BB105": {
"revision": 1,
"explanation": "On 80 m at night, intercontinental propagation is plausible, so 'CQ DX' asks for stations from other continents rather than nearby stations.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BB106": {
"revision": 1,
"explanation": "TX, RX, and TRX follow the transmit/receive naming convention: transmitter, receiver, and a combined transceiver.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BB107": {
"revision": 1,
"explanation": "CW names the continuous carrier used for Morse telegraphy; the information is keyed by interrupting or shifting that carrier.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BB108": {
"revision": 1,
"explanation": "BK is the telegraphy break signal: it interrupts the current transmission or hands over informally without the full closing sequence.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BB109": {
"revision": 1,
"explanation": "K is the procedural invitation to transmit, so it marks that the other station may answer.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BB110": {
"revision": 1,
"explanation": "R at the start of a telegraphy over means 'received', confirming that the previous transmission was copied.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BB201": {
"revision": 1,
"explanation": "These Q groups encode common reception conditions: QRM is man-made interference, QRN is atmospheric noise, and QSB asks about fading.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BB202": {
"revision": 1,
"explanation": "With a question mark, QRO asks about increasing power, QSO asks about direct communication, and QRX asks when the next call should happen.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BB203": {
"revision": 1,
"explanation": "QRT orders stopping transmission, QRZ asks who is calling, and QSL? asks whether reception can be confirmed.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BB204": {
"revision": 1,
"explanation": "QRV states readiness, QRM? asks whether interference is present, and QTH gives a station location.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BB205": {
"revision": 1,
"explanation": "QRP is the operating signal for reducing transmitter power, so 'PSE QRP' is a polite request to turn it down.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BB206": {
"revision": 1,
"explanation": "QSY is the operating signal for changing frequency, so 'PSE QSY' asks you to move to another frequency.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BC101": {
"revision": 1,
"explanation": "The 10 m amateur band is around 28 MHz, which lies in the 3-30 MHz HF shortwave range.",
"source": "ITU Radio Regulations, Article 2",
"confidence": 9
},
"BC102": {
"revision": 1,
"explanation": "The 2 m band is around 144-146 MHz, which lies in the 30-300 MHz VHF range.",
"source": "ITU Radio Regulations, Article 2",
"confidence": 9
},
"BC103": {
"revision": 1,
"explanation": "The 70 cm band is around 430-440 MHz, which lies in the 300-3000 MHz UHF range.",
"source": "ITU Radio Regulations, Article 2",
"confidence": 9
},
"BC104": {
"revision": 1,
"explanation": "HF is defined as 3-30 MHz; those wavelengths are roughly 100 m to 10 m, hence shortwave/KW.",
"source": "ITU Radio Regulations, Article 2",
"confidence": 9
},
"BC105": {
"revision": 1,
"explanation": "VHF is defined as 30-300 MHz; in German amateur practice this is the UKW range.",
"source": "ITU Radio Regulations, Article 2",
"confidence": 9
},
"BC106": {
"revision": 1,
"explanation": "UHF is defined as 300-3000 MHz; its wavelengths are in the decimetre range.",
"source": "ITU Radio Regulations, Article 2",
"confidence": 9
},
"BC201": {
"revision": 1,
"explanation": "IARU band plans are coordination recommendations, not law, but following them prevents incompatible modes from crowding each other.",
"source": "https://www.iaru-r1.org/wp-content/uploads/2021/06/hf_r1_bandplan.pdf",
"confidence": 7
},
"BC202": {
"revision": 1,
"explanation": "The HF band-plan convention uses lower sideband below 10 MHz, so 80 m normally uses LSB.",
"source": "https://www.iaru-r1.org/wp-content/uploads/2021/06/hf_r1_bandplan.pdf",
"confidence": 7
},
"BC203": {
"revision": 1,
"explanation": "The HF band-plan convention uses upper sideband above 10 MHz, so 20 m normally uses USB.",
"source": "https://www.iaru-r1.org/wp-content/uploads/2021/06/hf_r1_bandplan.pdf",
"confidence": 7
},
"BC204": {
"revision": 1,
"explanation": "Band plans put narrow Morse activity at the lower edge of most bands, leaving wider modes farther up the band.",
"source": "https://www.iaru-r1.org/wp-content/uploads/2021/06/hf_r1_bandplan.pdf",
"confidence": 7
},
"BC205": {
"revision": 1,
"explanation": "The Region 1 VHF plan marks 145.500 MHz as the 2 m FM calling frequency, so it is used for general FM calls.",
"source": "https://www.iaru-r1.org/wp-content/uploads/2024/11/VHF_Handbook_V10_02.pdf",
"confidence": 7
},
"BC206": {
"revision": 1,
"explanation": "The Region 1 UHF plan marks 433.500 MHz as the 70 cm FM calling frequency, so it is used for general FM calls.",
"source": "https://www.iaru-r1.org/wp-content/uploads/2024/11/VHF_Handbook_V10_02.pdf",
"confidence": 7
},
"BC207": {
"revision": 1,
"explanation": "The 2 m band plan lists 145.375 MHz for digital voice calling, separating it from analogue FM calling traffic.",
"source": "https://www.iaru-r1.org/wp-content/uploads/2024/11/VHF_Handbook_V10_02.pdf",
"confidence": 7
},
"BC208": {
"revision": 1,
"explanation": "The 70 cm band plan lists 433.450 MHz for digital voice calling, separating it from analogue FM calling traffic.",
"source": "https://www.iaru-r1.org/wp-content/uploads/2024/11/VHF_Handbook_V10_02.pdf",
"confidence": 7
},
"BC209": {
"revision": 1,
"explanation": "145.450 MHz falls in the 2 m FM simplex channel area, so it is suitable for an FM voice contact under the band plan.",
"source": "https://www.iaru-r1.org/wp-content/uploads/2024/11/VHF_Handbook_V10_02.pdf",
"confidence": 7
},
"BC210": {
"revision": 1,
"explanation": "144.310 MHz sits near the 144.300 MHz SSB centre of activity, so it is appropriate for 2 m SSB voice.",
"source": "https://www.iaru-r1.org/wp-content/uploads/2024/11/VHF_Handbook_V10_02.pdf",
"confidence": 7
},
"BC211": {
"revision": 1,
"explanation": "The 2 m band plan uses 144.300 MHz as the SSB centre of activity.",
"source": "https://www.iaru-r1.org/wp-content/uploads/2024/11/VHF_Handbook_V10_02.pdf",
"confidence": 7
},
"BC212": {
"revision": 1,
"explanation": "The 70 cm band plan uses 432.200 MHz as the SSB centre of activity.",
"source": "https://www.iaru-r1.org/wp-content/uploads/2024/11/VHF_Handbook_V10_02.pdf",
"confidence": 7
},
"BC213": {
"revision": 1,
"explanation": "144.075 MHz lies in the narrow Morse-preferred segment, so wider or keyboard digital modes should use their own segments.",
"source": "https://www.iaru-r1.org/wp-content/uploads/2024/11/VHF_Handbook_V10_02.pdf",
"confidence": 7
},
"BC214": {
"revision": 1,
"explanation": "Around 144.125 MHz the 2 m band plan is for Morse and narrow digital work, not local FM voice.",
"source": "https://www.iaru-r1.org/wp-content/uploads/2024/11/VHF_Handbook_V10_02.pdf",
"confidence": 7
},
"BC215": {
"revision": 1,
"explanation": "Around 144.450 MHz the 2 m band plan reserves beacon use, so an ordinary local FM QSO would occupy the wrong segment.",
"source": "https://www.iaru-r1.org/wp-content/uploads/2024/11/VHF_Handbook_V10_02.pdf",
"confidence": 7
},
"BC216": {
"revision": 1,
"explanation": "The 145.500-145.5625 MHz FM simplex area is channelised for narrow FM, so keeping to about 12 kHz avoids adjacent-channel interference.",
"source": "https://www.iaru-r1.org/wp-content/uploads/2024/11/VHF_Handbook_V10_02.pdf",
"confidence": 7
},
"BC217": {
"revision": 1,
"explanation": "145.600 MHz is in the 2 m repeater output area, so a direct local FM contact would interfere with repeater operation.",
"source": "https://www.iaru-r1.org/wp-content/uploads/2024/11/VHF_Handbook_V10_02.pdf",
"confidence": 7
},
"BC218": {
"revision": 1,
"explanation": "145.800 MHz belongs to the 2 m space-communication segment, so it should be kept clear for satellite and other space contacts.",
"source": "https://www.iaru-r1.org/wp-content/uploads/2024/11/VHF_Handbook_V10_02.pdf",
"confidence": 7
},
"BC219": {
"revision": 1,
"explanation": "432.040 MHz lies in the 70 cm Morse/narrow digital segment, so local FM voice would be the wrong bandwidth and mode there.",
"source": "https://www.iaru-r1.org/wp-content/uploads/2024/11/VHF_Handbook_V10_02.pdf",
"confidence": 7
},
"BC220": {
"revision": 1,
"explanation": "432.450 MHz is assigned to beacon activity in the 70 cm plan, so it should not be used for an ordinary local FM contact.",
"source": "https://www.iaru-r1.org/wp-content/uploads/2024/11/VHF_Handbook_V10_02.pdf",
"confidence": 7
},
"BC221": {
"revision": 1,
"explanation": "435.500 MHz lies in the 70 cm satellite segment, so terrestrial local FM would risk interfering with satellite operation.",
"source": "https://www.iaru-r1.org/wp-content/uploads/2024/11/VHF_Handbook_V10_02.pdf",
"confidence": 7
},
"BC222": {
"revision": 1,
"explanation": "439.200 MHz is in the 70 cm repeater output area, so a direct local FM contact would occupy repeater spectrum.",
"source": "https://www.iaru-r1.org/wp-content/uploads/2024/11/VHF_Handbook_V10_02.pdf",
"confidence": 7
},
"BD101": {
"revision": 1,
"explanation": "German club-station call signs use zero in the numeral position; DA0ABC therefore identifies a club station.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__10.html",
"confidence": 9
},
"BD102": {
"revision": 1,
"explanation": "AFuV §16 allows BNetzA to permit special experimental or technical-scientific studies and to make that dependent on assigning another call sign.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__16.html",
"confidence": 10
},
"BD103": {
"revision": 1,
"explanation": "DL0 is in the German club-station pattern for class A, and the zero distinguishes it from person-bound DL1-DL9 calls.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__10.html",
"confidence": 9
},
"BD104": {
"revision": 1,
"explanation": "In the German call-sign plan, DL1-DL9 with normal two- or three-letter suffixes are person-bound class A call signs.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__10.html",
"confidence": 9
},
"BD105": {
"revision": 1,
"explanation": "The German call-sign plan assigns DN9 to person-bound class N call signs.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__10.html",
"confidence": 9
},
"BD106": {
"revision": 1,
"explanation": "The German call-sign plan assigns DO1-DO9 with normal suffixes to person-bound class E call signs.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__10.html",
"confidence": 9
},
"BD107": {
"revision": 1,
"explanation": "DP0GVN is one of the German exterritorial class A station patterns; DP0 is used for special locations outside ordinary German territory.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BD108": {
"revision": 1,
"explanation": "DP0POL follows the same exterritorial class A pattern as other German Antarctic or special-location stations.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BD109": {
"revision": 1,
"explanation": "Low-power transmitters for direction finding may identify with short MO-series markers instead of a normal amateur call sign.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__11.html",
"confidence": 9
},
"BD201": {
"revision": 1,
"explanation": "The suffix /am means aeronautical mobile: the station is operating from an aircraft.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BD202": {
"revision": 1,
"explanation": "VE is a Canadian call-sign series, and /am adds that the station is being operated from an aircraft.",
"source": "https://www.itu.int/gladapp/Allocation/CallSigns",
"confidence": 9
},
"BD203": {
"revision": 1,
"explanation": "The suffix /m means mobile; for amateur operation that includes a station moving in a land vehicle.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BD204": {
"revision": 1,
"explanation": "The suffix /m can also mark mobile operation on inland waterways, distinct from /mm on the high seas.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BD205": {
"revision": 1,
"explanation": "The suffix /mm means maritime mobile, so the station is aboard a vessel at sea rather than on land or inland water.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BD206": {
"revision": 1,
"explanation": "The suffix /p is used as extra information for portable or temporarily fixed operation.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__11.html",
"confidence": 9
},
"BD207": {
"revision": 1,
"explanation": "AFuV allows internationally customary suffixes but does not require /p for portable or temporary fixed operation in Germany.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__11.html",
"confidence": 9
},
"BD208": {
"revision": 1,
"explanation": "AFuV §11 names Remote for speech and /R for telegraphy or digital modes when marking remote operation.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__11.html",
"confidence": 10
},
"BD209": {
"revision": 1,
"explanation": "For training operation, AFuV §11 requires /Trainee in speech, so the trainee uses the instructor's call sign plus that suffix.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__11.html",
"confidence": 10
},
"BD210": {
"revision": 1,
"explanation": "Training operation may use the club-station call sign, but AFuV §11 requires the training suffix /Trainee for speech or /T for telegraphy/digital modes.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__11.html",
"confidence": 10
},
"BD211": {
"revision": 1,
"explanation": "For training in Morse or digital modes, AFuV §11 requires the short /T suffix on the instructor's call sign.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__11.html",
"confidence": 10
},
"BD212": {
"revision": 1,
"explanation": "CEPT guest operation uses the visited country's prefix before the home call sign, so a UK G3MM station temporarily in Germany signs with DL/.",
"source": "https://docdb.cept.org/download/3321",
"confidence": 9
},
"BD213": {
"revision": 1,
"explanation": "CEPT Novice guest operation in Switzerland uses the Swiss novice visitor prefix HB3 before the German class E call sign.",
"source": "https://docdb.cept.org/download/2768",
"confidence": 9
},
"BD214": {
"revision": 1,
"explanation": "CEPT guest operation in Switzerland uses the Swiss HB9 prefix before the German class A call sign.",
"source": "https://docdb.cept.org/download/3321",
"confidence": 9
},
"BD301": {
"revision": 1,
"explanation": "Unknown prefixes are a lookup item: the ITU call-sign allocation table, handbooks, and callbooks map prefix blocks to countries.",
"source": "https://www.itu.int/gladapp/Allocation/CallSigns",
"confidence": 9
},
"BD302": {
"revision": 1,
"explanation": "ITU call-sign series split DA-DR to Germany, DS-DT to South Korea, and DU-DZ to the Philippines.",
"source": "https://www.itu.int/gladapp/Allocation/CallSigns",
"confidence": 9
},
"BD303": {
"revision": 1,
"explanation": "The ITU prefix table maps OE to Austria, ON to Belgium, and OK to Czechia.",
"source": "https://www.itu.int/gladapp/Allocation/CallSigns",
"confidence": 9
},
"BD304": {
"revision": 1,
"explanation": "The ITU prefix table maps OE to Austria, PA to the Netherlands, and SM to Sweden.",
"source": "https://www.itu.int/gladapp/Allocation/CallSigns",
"confidence": 9
},
"BD305": {
"revision": 1,
"explanation": "The ITU prefix table maps F to France, PA to the Netherlands, and SP to Poland.",
"source": "https://www.itu.int/gladapp/Allocation/CallSigns",
"confidence": 9
},
"BD306": {
"revision": 1,
"explanation": "The ITU prefix table maps SM to Sweden, SP to Poland, and ZS to South Africa.",
"source": "https://www.itu.int/gladapp/Allocation/CallSigns",
"confidence": 9
},
"BD307": {
"revision": 1,
"explanation": "The ITU prefix table maps 4X to Israel, F to France, and OZ to Denmark.",
"source": "https://www.itu.int/gladapp/Allocation/CallSigns",
"confidence": 9
},
"BD308": {
"revision": 1,
"explanation": "The ITU prefix table maps EA to Spain, EI to Ireland, EK to Armenia, EM to Ukraine, and ES to Estonia.",
"source": "https://www.itu.int/gladapp/Allocation/CallSigns",
"confidence": 9
},
"BD309": {
"revision": 1,
"explanation": "The ITU prefix table maps VE to Canada, VK to Australia, and PY to Brazil.",
"source": "https://www.itu.int/gladapp/Allocation/CallSigns",
"confidence": 9
},
"BD310": {
"revision": 1,
"explanation": "The ITU prefix table maps HB9 to Switzerland, EA to Spain, and ON to Belgium.",
"source": "https://www.itu.int/gladapp/Allocation/CallSigns",
"confidence": 9
},
"BD311": {
"revision": 1,
"explanation": "The ITU prefix table maps EA to Spain, LX to Luxembourg, and SP to Poland.",
"source": "https://www.itu.int/gladapp/Allocation/CallSigns",
"confidence": 9
},
"BD312": {
"revision": 1,
"explanation": "The ITU prefix table maps W to the United States, ZL to New Zealand, and LU to Argentina.",
"source": "https://www.itu.int/gladapp/Allocation/CallSigns",
"confidence": 9
},
"BD313": {
"revision": 1,
"explanation": "The ITU prefix table maps BY to China, VE to Canada, and VK to Australia.",
"source": "https://www.itu.int/gladapp/Allocation/CallSigns",
"confidence": 9
},
"BD314": {
"revision": 1,
"explanation": "F, HB9, OZ, and SP correspond to France, Switzerland, Denmark, and Poland, all neighbours of Germany.",
"source": "https://www.itu.int/gladapp/Allocation/CallSigns",
"confidence": 9
},
"BD315": {
"revision": 1,
"explanation": "K and W are United States call-sign series, so K3LR, W3DZZ, and K4EAX are all US-style calls.",
"source": "https://www.itu.int/gladapp/Allocation/CallSigns",
"confidence": 9
},
"BD316": {
"revision": 1,
"explanation": "W, VE, and XE identify the United States, Canada, and Mexico; all three are on North America.",
"source": "https://www.itu.int/gladapp/Allocation/CallSigns",
"confidence": 9
},
"BD317": {
"revision": 1,
"explanation": "PY, CE, and LU identify Brazil, Chile, and Argentina, all in South America.",
"source": "https://www.itu.int/gladapp/Allocation/CallSigns",
"confidence": 9
},
"BD318": {
"revision": 1,
"explanation": "BY, JA, and VU identify China, Japan, and India, all in Asia.",
"source": "https://www.itu.int/gladapp/Allocation/CallSigns",
"confidence": 9
},
"BE101": {
"revision": 1,
"explanation": "A contact starts either as a general call, a directed call, or an answer to a call; in every case the own call sign identifies the transmitting station.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__11.html",
"confidence": 9
},
"BE102": {
"revision": 1,
"explanation": "Answering CQ first names the station being called, then gives your own call sign once, which makes both sides of the intended contact clear.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE103": {
"revision": 1,
"explanation": "A partial call containing your suffix is not enough certainty, so asking whether you were called avoids answering for another station.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE104": {
"revision": 1,
"explanation": "In English phone procedure, name the station you are calling first and then identify yourself with 'this is' plus your call sign.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE105": {
"revision": 1,
"explanation": "A clear frequency may still be in use, so asking whether it is occupied before calling CQ reduces accidental interference.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE106": {
"revision": 1,
"explanation": "On higher HF bands, skip propagation can create a dead zone: you may not hear a nearby station that is nevertheless using the frequency.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE107": {
"revision": 1,
"explanation": "145.500 MHz is a calling channel; after contact is made, moving by QSY keeps the calling channel available for others.",
"source": "https://www.iaru-r1.org/wp-content/uploads/2024/11/VHF_Handbook_V10_02.pdf",
"confidence": 7
},
"BE108": {
"revision": 1,
"explanation": "After your CQ contact ends, the original frequency should not become a queue; arranging QSY keeps the calling or working frequency usable.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE109": {
"revision": 1,
"explanation": "On 2 m and 70 cm, 'DX' means well beyond normal local range, so local or nearby stations should wait.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE110": {
"revision": 1,
"explanation": "CQ VK/ZL is a directed CQ for Australia and New Zealand prefixes, so a non-VK/ZL station should not answer.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE111": {
"revision": 1,
"explanation": "The Maidenhead locator encodes geographic position into grid fields and squares, giving a compact location reference for radio contacts.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE112": {
"revision": 1,
"explanation": "A CW CQ repeats CQ and the own call sign, uses DE for 'from', and ends with K to invite replies.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE113": {
"revision": 1,
"explanation": "CQ DL is a directed general call for German stations, and PSE K politely invites those stations to answer.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE114": {
"revision": 1,
"explanation": "CQ DX on 20 m asks for distant intercontinental contacts; a European station should not answer a Swiss station's DX call.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE115": {
"revision": 1,
"explanation": "QRZ? asks 'who is calling me?' and in a pile-up it is also used to invite the next callers.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE116": {
"revision": 1,
"explanation": "CQ FD and TEST mark contest traffic for Field Day, and /P says the station is operating portable.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE117": {
"revision": 1,
"explanation": "Matching or slowing down to the caller's Morse speed improves copy and avoids forcing the other operator beyond their receive speed.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE118": {
"revision": 1,
"explanation": "Morse should be sent no faster than you can copy and adjusted to slower stations, because reliable exchange matters more than speed.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE201": {
"revision": 1,
"explanation": "RST is a compact reception report, so it summarizes how well the signal can be read and, where relevant, its strength and tone.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE202": {
"revision": 1,
"explanation": "The letters name the three report dimensions: Readability, Strength, and Tone.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE203": {
"revision": 1,
"explanation": "The RST scale uses R 1-5 for readability, S 1-9 for signal strength, and T 1-9 for tone quality.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE204": {
"revision": 2,
"explanation": "On the analogue S-meter, the needle indicates S5. For SSB phone the tone digit is omitted; clear copy gives R5, so the report is 55.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE205": {
"revision": 2,
"explanation": "On the analogue S-meter, the needle indicates S9. For SSB phone the tone digit is omitted; clear copy gives R5, so the report is 59.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE206": {
"revision": 2,
"explanation": "On the analogue S-meter, the needle is 20 dB over S9. For SSB phone the tone digit is omitted, so clear copy is reported as 59+20 dB.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE207": {
"revision": 2,
"explanation": "On the digital display, the shown signal level is S5. For SSB phone the tone digit is omitted; clear copy gives R5, so the report is 55.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE208": {
"revision": 2,
"explanation": "On the digital display, the shown signal level is S9. For SSB phone the tone digit is omitted; clear copy gives R5, so the report is 59.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE209": {
"revision": 2,
"explanation": "On the digital display, the shown signal level is 20 dB over S9. For SSB phone the tone digit is omitted, so clear copy is reported as 59+20 dB.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE210": {
"revision": 1,
"explanation": "SSTV sends pictures, so the practical way to report image quality is to include the report text in the transmitted image itself.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE301": {
"revision": 1,
"explanation": "Contests are structured operating exercises: competition pressure improves station setup, operator skill, and operating technique.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__2.html",
"confidence": 9
},
"BE302": {
"revision": 1,
"explanation": "Contest scoring rewards many valid contacts in limited time, so exchanges are deliberately short and standardized.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE303": {
"revision": 1,
"explanation": "A contest QSO counts only if both stations exchange the data required by that contest's rules.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE304": {
"revision": 1,
"explanation": "In a Sprint contest, handing over the frequency after each QSO prevents one station from holding the run frequency continuously.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE305": {
"revision": 1,
"explanation": "A pile-up is what happens when many stations call the same desirable station at once.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE306": {
"revision": 1,
"explanation": "'Only number 3' filters a pile-up by the numeral in the call sign, so only calls with 3 between prefix and suffix should call.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE307": {
"revision": 1,
"explanation": "List operation uses a strong control station to collect callers and call them in order, reducing chaos around a rare station.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE308": {
"revision": 1,
"explanation": "Split operation separates transmit and receive frequencies, letting a rare station listen where callers transmit while keeping its own transmit frequency clear.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE309": {
"revision": 1,
"explanation": "'Split up 14270 to 14280' means the station transmits on its announced frequency but listens for callers across that higher range.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE310": {
"revision": 1,
"explanation": "'5 up' means the wanted station listens 5 kHz above its transmit frequency, so callers must transmit there and listen on the station's frequency.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE311": {
"revision": 1,
"explanation": "'Tuning 290 to 300 up' gives the listening window by shorthand: transmit between 14290 and 14300 kHz while listening to 14205 kHz.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE312": {
"revision": 1,
"explanation": "A DX-pedition deliberately activates a rare country or island so other amateurs can work a location that is normally hard to hear.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE313": {
"revision": 1,
"explanation": "ARDF is a direction-finding contest: operators use portable receivers to locate hidden low-power transmitters that transmit briefly.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE401": {
"revision": 1,
"explanation": "A repeater is duplex: users transmit to its input, and the repeater retransmits what it hears on its output.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE402": {
"revision": 1,
"explanation": "German 2 m repeaters conventionally use a -600 kHz shift, so the input is 600 kHz below the output.",
"source": "https://www.iaru-r1.org/wp-content/uploads/2024/11/VHF_Handbook_V10_02.pdf",
"confidence": 7
},
"BE403": {
"revision": 1,
"explanation": "German 70 cm repeaters conventionally use a -7.6 MHz shift, so the input is 7.6 MHz below the output.",
"source": "https://www.iaru-r1.org/wp-content/uploads/2024/11/VHF_Handbook_V10_02.pdf",
"confidence": 7
},
"BE404": {
"revision": 1,
"explanation": "A short pause before each over leaves a gap for another station to break in without doubling.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE405": {
"revision": 1,
"explanation": "Clear handover tells everyone whose turn it is, which prevents two stations from transmitting at the same time.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE406": {
"revision": 1,
"explanation": "Repeaters are shared resources, and short overs leave access opportunities for mobile and portable users with changing signal conditions.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE407": {
"revision": 1,
"explanation": "Wide FM spills into adjacent repeater inputs and can overdrive a narrow repeater receiver, causing interference or distorted retransmission.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE408": {
"revision": 1,
"explanation": "Over a repeater, your S-meter reads the repeater's downlink, not the other user's uplink, so only readability describes the other user's signal.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE409": {
"revision": 1,
"explanation": "Beacons provide known reference signals; hearing or not hearing them indicates current propagation conditions.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE410": {
"revision": 1,
"explanation": "The International Beacon Project uses fixed beacon slots, so keeping those narrow ranges clear preserves their propagation-monitoring value.",
"source": "https://www.iaru-r1.org/wp-content/uploads/2021/06/hf_r1_bandplan.pdf",
"confidence": 7
},
"BE411": {
"revision": 1,
"explanation": "Uplink is the direction from an earth station up to the satellite.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE412": {
"revision": 1,
"explanation": "Downlink is the direction from the satellite down to earth stations.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE413": {
"revision": 1,
"explanation": "Azimuth is the horizontal bearing angle used to point an antenna around the horizon.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE414": {
"revision": 1,
"explanation": "Elevation is the vertical pointing angle above the horizon used to track a satellite.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE415": {
"revision": 1,
"explanation": "OSCAR expands to Orbiting Satellite Carrying Amateur Radio, the usual name for amateur-radio satellites.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BE416": {
"revision": 1,
"explanation": "A satellite transponder receives signals on one band, translates them to another frequency range, and retransmits them back toward Earth.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BF101": {
"revision": 1,
"explanation": "Outside amateur radio, the internationally recognised distress signals are Mayday for voice and SOS for Morse or signalling.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BF102": {
"revision": 1,
"explanation": "AFuV §16 forbids using the international distress, urgency, and safety signals of maritime and aeronautical mobile services in amateur radio.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__16.html",
"confidence": 10
},
"BF103": {
"revision": 1,
"explanation": "If normal communication is unavailable, amateur radio can support emergency assistance by relaying the request to someone who can contact police or rescue services.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__2.html",
"confidence": 9
},
"BF104": {
"revision": 1,
"explanation": "The first task is accurate copying: listen and write down facts before transmitting so the emergency information is not lost or distorted.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BF105": {
"revision": 1,
"explanation": "If a rescue organisation has taken the traffic, extra amateur transmissions only risk interference, so the right action is to stay clear.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BF106": {
"revision": 1,
"explanation": "When no one else answers and you can help, acknowledging the distress traffic and alerting official emergency services is the useful relay path.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__2.html",
"confidence": 9
},
"BF107": {
"revision": 1,
"explanation": "After relaying a distress message, remaining reachable lets you pass updates until professional help arrives or releases you.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BF108": {
"revision": 1,
"explanation": "Germany is UTC+2 during MESZ, so 23:00 UTC is 01:00 MESZ on the following local date.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BF109": {
"revision": 1,
"explanation": "IARU Region 1 designates these HF centres of activity for emergency communication, so they should be kept clear for that use.",
"source": "https://www.iaru-r1.org/about-us/committees-and-working-groups/emcomm/emergency-communications-frequencies/",
"confidence": 7
},
"BG101": {
"revision": 1,
"explanation": "A logbook is the station diary: usually voluntary, but it can become mandatory when required for a particular station or case.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BG102": {
"revision": 1,
"explanation": "If log keeping is ordered, a computer log must remain readable for the required period just like a paper log.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BG103": {
"revision": 1,
"explanation": "Changing log software must not make ordered log data inaccessible, because the records may need later inspection.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BG104": {
"revision": 1,
"explanation": "A QSL card confirms that a QSO took place and can serve as evidence for awards that require worked stations or countries.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BG105": {
"revision": 1,
"explanation": "A useful QSL must identify both stations and the contact: call signs, UTC date/time, band, mode, and signal report are the minimum facts.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BG106": {
"revision": 1,
"explanation": "UTC avoids local time-zone and daylight-saving ambiguity, making it easier for foreign stations to match the card to their log.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BG107": {
"revision": 1,
"explanation": "MEZ is UTC+1, so 15:30 local standard time is 14:30 UTC.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BG108": {
"revision": 1,
"explanation": "MESZ is UTC+2, so 13:30 local daylight-saving time is 11:30 UTC.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BG109": {
"revision": 1,
"explanation": "'QSL via K8PYD' means K8PYD manages cards for HZ1HZ, so sending through that manager is the route to confirmation.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BG110": {
"revision": 1,
"explanation": "Direct QSL mailing needs a current address, which is why operators use callbooks or online call-sign information.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"BG111": {
"revision": 1,
"explanation": "Electronic QSL systems and log uploads confirm the same QSO facts without exchanging a physical card.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"EA101": {
"revision": 1,
"explanation": "Capacitance is charge stored per voltage, $C = Q/U$, and its named SI-derived unit is the farad.",
"source": "https://50ohm.de/EA_kondensator_1.html",
"confidence": 8
},
"EA102": {
"revision": 1,
"explanation": "Inductance describes magnetic flux linkage per current; the named SI-derived unit for it is the henry.",
"source": "https://50ohm.de/EA_spule_1.html",
"confidence": 8
},
"EA103": {
"revision": 1,
"explanation": "For a plate field, $E = U/d$, so the unit is volts divided by metres: V/m.",
"source": "https://50ohm.de/EA_e_feld.html",
"confidence": 8
},
"EA104": {
"revision": 1,
"explanation": "For a long straight conductor, $H = I/(2\\pi r)$, so magnetic field strength has amperes divided by metres: A/m.",
"source": "https://50ohm.de/EA_h_feld.html",
"confidence": 8
},
"EA105": {
"revision": 2,
"explanation": "Bandwidth is a frequency interval, so it is measured in hertz just like frequency.",
"source": "https://50ohm.de/E_slide_e_modulation.html",
"confidence": 7
},
"EA106": {
"revision": 1,
"explanation": "A data rate counts transferred bits per unit time, so the usual unit is bit/s rather than baud or hertz.",
"source": "https://50ohm.de/NEA_datenuebertragungsdrate.html",
"confidence": 8
},
"EA107": {
"revision": 1,
"explanation": "Power ratios in dB use $10\\log_{10}(P_2/P_1)$; doubling power gives $10\\log_{10}(2) \\approx 3$ dB.",
"source": "https://50ohm.de/E_dezibel_1.html",
"confidence": 8
},
"EA108": {
"revision": 1,
"explanation": "$0.00042$ A equals $420 \\cdot 10^{-6}$ A because moving the decimal six places expresses the value in micro-units.",
"source": "https://50ohm.de/NEA_zehnerpotenzen.html",
"confidence": 8
},
"EA109": {
"revision": 1,
"explanation": "$0.042$ A equals $42 \\cdot 10^{-3}$ A because milli means $10^{-3}$.",
"source": "https://50ohm.de/NEA_zehnerpotenzen.html",
"confidence": 8
},
"EA110": {
"revision": 1,
"explanation": "$4,200,000$ Hz is $4.2 \\cdot 10^6$ Hz in scientific notation.",
"source": "https://50ohm.de/NEA_zehnerpotenzen.html",
"confidence": 8
},
"EA111": {
"revision": 1,
"explanation": "$0.01$ mV is $0.01 \\cdot 10^{-3}$ V, which is $10 \\cdot 10^{-6}$ V.",
"source": "https://50ohm.de/NEA_zehnerpotenzen.html",
"confidence": 8
},
"EA112": {
"revision": 1,
"explanation": "$0.002$ MOhm is $0.002 \\cdot 10^6$ ohm, which is $2 \\cdot 10^3$ ohm.",
"source": "https://50ohm.de/NEA_zehnerpotenzen.html",
"confidence": 8
},
"EA113": {
"revision": 1,
"explanation": "$2 \\cdot 10^{-7}$ W divided by $10^{-6}$ W/µW gives $0.2$ µW.",
"source": "https://50ohm.de/NEA_zehnerpotenzen.html",
"confidence": 8
},
"EA114": {
"revision": 1,
"explanation": "$5 \\cdot 10^{-1}$ W is $0.5$ W; multiplying by 1000 converts that to 500 mW.",
"source": "https://50ohm.de/NEA_zehnerpotenzen.html",
"confidence": 8
},
"EA115": {
"revision": 1,
"explanation": "Micro is $10^{-6}$ and nano is $10^{-9}$, so $0.22$ µF is $0.22 \\cdot 1000 = 220$ nF.",
"source": "https://50ohm.de/NEA_zehnerpotenzen.html",
"confidence": 8
},
"EA116": {
"revision": 1,
"explanation": "Kilo to mega divides by 1000, so 3750 kHz is 3.750 MHz.",
"source": "https://50ohm.de/NEA_zehnerpotenzen.html",
"confidence": 8
},
"EA201": {
"revision": 1,
"explanation": "Digital circuits can represent two robust electrical states as 0 and 1, so binary maps naturally to switching devices such as transistors.",
"source": "https://50ohm.de/EA_binaer.html",
"confidence": 8
},
"EA202": {
"revision": 1,
"explanation": "Each bit doubles the number of possible states; with 3 bits there are $2^3 = 8$ states.",
"source": "https://50ohm.de/EA_binaer.html",
"confidence": 8
},
"EA203": {
"revision": 1,
"explanation": "Each bit doubles the number of possible states; with 4 bits there are $2^4 = 16$ states.",
"source": "https://50ohm.de/EA_binaer.html",
"confidence": 8
},
"EA204": {
"revision": 1,
"explanation": "A five-bit binary number has $2^5$ possible combinations, so it can represent 32 values.",
"source": "https://50ohm.de/EA_binaer.html",
"confidence": 8
},
"EA205": {
"revision": 1,
"explanation": "$01001110_2 = 64 + 8 + 4 + 2 = 78$; the leading zero only pads the width.",
"source": "https://50ohm.de/EA_binaer.html",
"confidence": 8
},
"EA206": {
"revision": 1,
"explanation": "$10001110_2 = 128 + 8 + 4 + 2 = 142$.",
"source": "https://50ohm.de/EA_binaer.html",
"confidence": 8
},
"EA207": {
"revision": 1,
"explanation": "$10011100_2 = 128 + 16 + 8 + 4 = 156$.",
"source": "https://50ohm.de/EA_binaer.html",
"confidence": 8
},
"EA208": {
"revision": 1,
"explanation": "$11111000_2 = 128 + 64 + 32 + 16 + 8 = 248$.",
"source": "https://50ohm.de/EA_binaer.html",
"confidence": 8
},
"EB101": {
"revision": 2,
"explanation": "Between large parallel plates the field lines are almost straight, parallel, and evenly spaced, so the approximation is a homogeneous electric field.",
"source": "https://50ohm.de/NEA_slide_nea_em_feld.html",
"confidence": 8
},
"EB102": {
"revision": 2,
"explanation": "For a plate capacitor, $E = U/d$. With $d = 0.6$ cm $= 0.006$ m, $E = 9/0.006 = 1500$ V/m.",
"source": "https://50ohm.de/NEA_slide_nea_em_feld.html",
"confidence": 8
},
"EB103": {
"revision": 2,
"explanation": "Use $E = U/d$ and convert $0.15$ mm to $1.5 \\cdot 10^{-4}$ m. Thus $300/(1.5 \\cdot 10^{-4}) = 2.0 \\cdot 10^6$ V/m = 2000 kV/m.",
"source": "https://50ohm.de/NEA_slide_nea_em_feld.html",
"confidence": 8
},
"EB104": {
"revision": 2,
"explanation": "Breakdown strength is an electric field strength, so $U = E \\cdot d$. $400$ kV/cm across $0.15$ mm gives $400 \\cdot 0.015 = 6$ kV.",
"source": "https://50ohm.de/NEA_slide_nea_em_feld.html",
"confidence": 8
},
"EB105": {
"revision": 2,
"explanation": "At a vertical antenna the electric field lines run between the conductor and the surrounding reference/ground; the concentric loops around the conductor are the magnetic field, not the marked vertical electric lines.",
"source": "https://50ohm.de/NEA_slide_nea_em_feld.html",
"confidence": 7
},
"EB201": {
"revision": 1,
"explanation": "A current through a straight conductor creates magnetic field lines that close around the conductor; in the simple straight-wire case they are concentric circles.",
"source": "https://50ohm.de/EA_h_feld.html",
"confidence": 8
},
"EB202": {
"revision": 2,
"explanation": "A long current-carrying solenoid concentrates nearly parallel magnetic field lines inside the winding, so its interior field is approximately homogeneous and magnetic.",
"source": "https://50ohm.de/NEA_slide_nea_em_feld.html",
"confidence": 8
},
"EB203": {
"revision": 1,
"explanation": "For a toroidal core, $H = NI/l_m$ with $l_m = \\pi d$. Here $H = 6 \\cdot 2.5/(\\pi \\cdot 0.026) \\approx 183.6$ A/m.",
"source": "https://50ohm.de/NEA_slide_nea_em_feld.html?print-pdf=&showNotes=true",
"confidence": 8
},
"EB204": {
"revision": 1,
"explanation": "Iron is ferromagnetic at room temperature; copper and aluminium are not ferromagnetic, and chromium is not the standard room-temperature ferromagnet used here.",
"source": "https://50ohm.de/E_spule_1.html",
"confidence": 8
},
"EB205": {
"revision": 3,
"explanation": "Eddy currents induced in the conductive copper or aluminium core oppose the changing RF flux, partially cancelling the field inside the core and shrinking the effective magnetic cross-section, so inductance drops. The catalog phrases this as the field 'not penetrating' the core — a simplification of what physically happens, but the wording to memorize.",
"source": "https://50ohm.de/NEA_spule_1.html",
"confidence": 7
},
"EB206": {
"revision": 2,
"explanation": "Around a vertical current-carrying antenna conductor, the closed concentric loops are magnetic field lines. The electric field lines are the open/vertical ones tied to the conductor and ground reference.",
"source": "https://50ohm.de/NEA_slide_nea_em_feld.html",
"confidence": 7
},
"EB301": {
"revision": 2,
"explanation": "Radio radiation needs time-varying fields. A time-varying current in a conductor, such as an antenna, produces coupled electric and magnetic field components.",
"source": "https://50ohm.de/NEA_slide_nea_em_feld.html",
"confidence": 8
},
"EB302": {
"revision": 2,
"explanation": "An electromagnetic wave propagates because changing electric and magnetic fields continually sustain each other; neither field travels independently in the far-field wave model.",
"source": "https://50ohm.de/NEA_slide_nea_em_feld.html",
"confidence": 8
},
"EB303": {
"revision": 1,
"explanation": "In free-space far-field propagation the electric and magnetic field vectors are transverse to each other, so their angle is $90^\\circ$.",
"source": "https://50ohm.de/NEA_fernfeld.html",
"confidence": 8
},
"EB304": {
"revision": 1,
"explanation": "In an undisturbed far field, the $E$ field, $H$ field, and propagation direction form a mutually perpendicular triad.",
"source": "https://50ohm.de/NEA_fernfeld.html",
"confidence": 8
},
"EB305": {
"revision": 2,
"explanation": "Electromagnetic-wave polarization is defined by the orientation or motion of the electric-field vector, not by the magnetic field or travel direction.",
"source": "https://50ohm.de/NEA_polarisation_2.html",
"confidence": 8
},
"EB306": {
"revision": 2,
"explanation": "Polarization follows the electric-field vector in the drawing. Here that vector lies horizontally, so the wave is horizontally polarized.",
"source": "https://50ohm.de/NEA_polarisation_2.html",
"confidence": 7
},
"EB307": {
"revision": 2,
"explanation": "Polarization is read from the electric-field vector. In this figure the electric field is vertical, so the wave is vertically polarized.",
"source": "https://50ohm.de/NEA_polarisation_2.html",
"confidence": 7
},
"EB308": {
"revision": 2,
"explanation": "When the electric-field direction rotates during propagation rather than staying along one fixed line, the wave is circularly polarized.",
"source": "https://50ohm.de/NEA_polarisation_2.html",
"confidence": 7
},
"EB309": {
"revision": 2,
"explanation": "For a linear antenna, the transmitted wave's polarization follows the orientation of the radiating element in the main direction. The shown elements are horizontal, so the signal is horizontally polarized.",
"source": "https://50ohm.de/NEA_polarisation_2.html",
"confidence": 7
},
"EB310": {
"revision": 2,
"explanation": "A linearly radiating element gives polarization in the same orientation as the electric field it launches. The shown main-direction field is vertical, so the signal is vertically polarized.",
"source": "https://50ohm.de/NEA_polarisation_2.html",
"confidence": 7
},
"EB311": {
"revision": 1,
"explanation": "Use $\\lambda = c/f$ with $c \\approx 300$ Mm/s. $300/1.84 \\approx 163$, so 1.84 MHz corresponds to about 163 m.",
"source": "https://50ohm.de/NE_wellenlaenge_2.html",
"confidence": 8
},
"EB312": {
"revision": 1,
"explanation": "Using $\\lambda \\approx 300/f_{MHz}$, $300/21 \\approx 14.29$ m.",
"source": "https://50ohm.de/NE_wellenlaenge_2.html",
"confidence": 8
},
"EB313": {
"revision": 1,
"explanation": "Using $\\lambda \\approx 300/f_{MHz}$, $300/28.5 \\approx 10.5$ m.",
"source": "https://50ohm.de/NE_wellenlaenge_2.html",
"confidence": 8
},
"EB314": {
"revision": 1,
"explanation": "Rearrange $\\lambda = c/f$ to $f \\approx 300/\\lambda$ in MHz for metres. $300/80.0 = 3.75$ MHz.",
"source": "https://50ohm.de/NE_wellenlaenge_2.html",
"confidence": 8
},
"EB315": {
"revision": 1,
"explanation": "A wavelength of 30 mm is 0.03 m. $f = c/\\lambda \\approx 3 \\cdot 10^8 / 0.03 = 1 \\cdot 10^{10}$ Hz = 10 GHz.",
"source": "https://50ohm.de/NE_wellenlaenge_2.html",
"confidence": 8
},
"EB316": {
"revision": 1,
"explanation": "A wavelength of 10 cm is 0.1 m. $f = c/\\lambda \\approx 3 \\cdot 10^8 / 0.1 = 3 \\cdot 10^9$ Hz = 3 GHz.",
"source": "https://50ohm.de/NE_wellenlaenge_2.html",
"confidence": 8
},
"EB401": {
"revision": 2,
"explanation": "For a sine wave, the peak value is RMS times sqrt(2). Mains 230 V is an RMS value, so 230 * 1.414 is about 325 V.",
"source": "https://50ohm.de/E_slide_e_strom_spannung_widerstand_leistung_energie.html",
"confidence": 8
},
"EB402": {
"revision": 2,
"explanation": "Peak-to-peak voltage is twice the peak value. From 230 V RMS, the peak is about 325 V, so peak-to-peak is about 650 V, rounded here to 651 V.",
"source": "https://50ohm.de/E_slide_e_strom_spannung_widerstand_leistung_energie.html",
"confidence": 8
},
"EB403": {
"revision": 2,
"explanation": "For a sine wave, peak voltage is RMS times sqrt(2): 12 V * 1.414 is about 17 V. Peak-to-peak is twice that, about 34 V.",
"source": "https://50ohm.de/E_slide_e_strom_spannung_widerstand_leistung_energie.html",
"confidence": 8
},
"EB404": {
"revision": 2,
"explanation": "For a sine wave, RMS is peak divided by sqrt(2). 12 V / 1.414 is about 8.5 V.",
"source": "https://50ohm.de/E_slide_e_strom_spannung_widerstand_leistung_energie.html",
"confidence": 8
},
"EB405": {
"revision": 2,
"explanation": "A DC voltage that gives the same heating power as a sine wave is the RMS value. For a 1 V sine peak, RMS is 1/sqrt(2), about 0.7 V in either polarity.",
"source": "https://50ohm.de/E_slide_e_strom_spannung_widerstand_leistung_energie.html",
"confidence": 8
},
"EB406": {
"revision": 2,
"explanation": "Peak-to-peak voltage is the vertical distance from the lowest trough to the highest crest on the screen. Reading the divisions in the shown trace gives 12 V.",
"source": "https://50ohm.de/E_slide_e_strom_spannung_widerstand_leistung_energie.html",
"confidence": 7
},
"EB407": {
"revision": 2,
"explanation": "The peak-to-peak value is twice the peak value shown in the diagram. A 20 V peak therefore gives 40 V peak-to-peak.",
"source": "https://50ohm.de/E_slide_e_strom_spannung_widerstand_leistung_energie.html",
"confidence": 7
},
"EB408": {
"revision": 2,
"explanation": "Frequency is the reciprocal of period: f = 1/T. With T = 50 microseconds, f = 1/(50e-6 s) = 20000 Hz = 20 kHz.",
"source": "https://50ohm.de/E_slide_e_strom_spannung_widerstand_leistung_energie.html",
"confidence": 8
},
"EB409": {
"revision": 2,
"explanation": "Read one period from the oscilloscope grid, then use f = 1/T. The trace period is about 12 microseconds, so f is about 83.3 kHz.",
"source": "https://50ohm.de/E_slide_e_strom_spannung_widerstand_leistung_energie.html",
"confidence": 7
},
"EB410": {
"revision": 2,
"explanation": "The oscilloscope trace spans 4 divisions at 5 ms/div, so T = 20 ms. f = 1/0.020 s = 50 Hz.",
"source": "https://50ohm.de/E_slide_e_strom_spannung_widerstand_leistung_energie.html",
"confidence": 7
},
"EB411": {
"revision": 2,
"explanation": "The trace period is 4 divisions at 0.03 microseconds/div, so T = 0.12 microseconds. f = 1/T is about 8.33 MHz.",
"source": "https://50ohm.de/NE_oszilloskop_1.html",
"confidence": 7
},
"EB501": {
"revision": 1,
"explanation": "PEP is defined at the crest of the modulation envelope: it is the average power over one RF cycle at that highest envelope point under normal operating conditions.",
"source": "https://life.itu.int/radioclub/rr/art1.pdf",
"confidence": 9
},
"EB502": {
"revision": 1,
"explanation": "Mean transmitter power is averaged over a time interval long enough compared with the lowest modulation frequency period, so it describes the longer-term power delivered to the antenna feed line.",
"source": "https://life.itu.int/radioclub/rr/art1.pdf",
"confidence": 9
},
"EB503": {
"revision": 1,
"explanation": "For a purely ohmic load, AC power formulas keep the same form when voltage and current are RMS values. Peak values would overstate the heating power.",
"source": "https://50ohm.de/EA_leistung_2.html",
"confidence": 8
},
"EB504": {
"revision": 1,
"explanation": "Combine P = U * I with Ohm's law I = U/R to get P = U^2/R. Solving for voltage gives U = sqrt(P * R).",
"source": "https://50ohm.de/EA_leistung_2.html",
"confidence": 8
},
"EB505": {
"revision": 1,
"explanation": "From P = I^2 * R, current is I = sqrt(P/R). From P = U^2/R, voltage is U = sqrt(P * R).",
"source": "https://50ohm.de/EA_leistung_2.html",
"confidence": 8
},
"EB506": {
"revision": 1,
"explanation": "Rearrange P = U^2/R to get R = U^2/P, and rearrange P = I^2 * R to get R = P/I^2.",
"source": "https://50ohm.de/EA_leistung_2.html",
"confidence": 8
},
"EB507": {
"revision": 1,
"explanation": "Use RMS voltage in P = U^2/R for the 50 Ohm load. 100^2/50 = 10000/50 = 200 W.",
"source": "https://50ohm.de/EA_leistung_2.html",
"confidence": 8
},
"EB508": {
"revision": 1,
"explanation": "Use P = I^2 * R with RMS current. 2^2 * 50 = 4 * 50 = 200 W.",
"source": "https://50ohm.de/EA_leistung_2.html",
"confidence": 8
},
"EB509": {
"revision": 1,
"explanation": "The resistor power is P = U^2/R. With 10 V across 100 Ohm, P = 100/100 = 1.00 W, so the rating must be at least that.",
"source": "https://50ohm.de/EA_leistung_2.html",
"confidence": 8
},
"EB510": {
"revision": 1,
"explanation": "Check both limits. The power limit gives U = sqrt(P * R) = sqrt(1 W * 10000 Ohm) = 100 V, which is below the 700 V voltage limit.",
"source": "https://50ohm.de/EA_leistung_2.html",
"confidence": 8
},
"EB511": {
"revision": 1,
"explanation": "The power limit gives U = sqrt(P * R) = sqrt(6 W * 100000 Ohm) about 775 V. That is below the 1000 V voltage rating, so power is the limiting factor.",
"source": "https://50ohm.de/EA_leistung_2.html",
"confidence": 8
},
"EB512": {
"revision": 1,
"explanation": "From P = I^2 * R, I = sqrt(P/R). sqrt(23.0/120) is about 0.438 A, or 438 mA.",
"source": "https://50ohm.de/EA_leistung_2.html",
"confidence": 8
},
"EB513": {
"revision": 1,
"explanation": "A 25 V peak-to-peak sine has a 12.5 V peak, so RMS voltage is 12.5/sqrt(2) about 8.84 V. Through 1000 Ohm, that is about 8.8 mA RMS.",
"source": "https://50ohm.de/EA_leistung_2.html",
"confidence": 8
},
"EB514": {
"revision": 1,
"explanation": "With 11 equal resistors in parallel, each resistor can still dissipate 5 W. The total rating is 11 * 5 W = 55 W.",
"source": "https://50ohm.de/EA_leistung_2.html",
"confidence": 8
},
"EC101": {
"revision": 1,
"explanation": "Wirewound resistors can dissipate high power, but the winding adds inductance, so they are best suited to DC and low-frequency high-load use.",
"source": "https://50ohm.de/E_widerstand_materialien.html",
"confidence": 8
},
"EC102": {
"revision": 1,
"explanation": "Metal-film resistors are made for tight value tolerance and low temperature dependence, which is why they are used as precision resistors.",
"source": "https://50ohm.de/E_widerstand_materialien.html",
"confidence": 8
},
"EC103": {
"revision": 1,
"explanation": "Metal-oxide film resistors are relatively low-inductance and stable at higher frequencies, unlike wirewound parts whose winding behaves like an inductor.",
"source": "https://50ohm.de/E_widerstand_materialien.html",
"confidence": 8
},
"EC104": {
"revision": 1,
"explanation": "A VHF/UHF dummy load should behave like a pure resistance. Low stray inductance and capacitance keep the impedance near 50 Ohm as frequency rises.",
"source": "https://50ohm.de/E_widerstand_materialien.html",
"confidence": 8
},
"EC105": {
"revision": 1,
"explanation": "Ten 500 Ohm resistors in parallel give 500/10 = 50 Ohm. Carbon-film parts avoid the wirewound inductance that would spoil a dummy load at RF.",
"source": "https://50ohm.de/E_widerstand_materialien.html",
"confidence": 8
},
"EC106": {
"revision": 1,
"explanation": "Ten equal 500 Ohm resistors in parallel give 50 Ohm, and unwound carbon-film parts keep parasitic inductance low enough for this RF dummy-load use.",
"source": "https://50ohm.de/E_widerstand_materialien.html",
"confidence": 8
},
"EC107": {
"revision": 1,
"explanation": "For VHF dummy loads, unwound metal-oxide resistors are preferred because they can be made low-inductance and thermally robust.",
"source": "https://50ohm.de/E_widerstand_materialien.html",
"confidence": 8
},
"EC108": {
"revision": 1,
"explanation": "NTC thermistors have a deliberately temperature-dependent resistance, making them useful as temperature sensors.",
"source": "https://50ohm.de/E_widerstand_ntc_ptc.html",
"confidence": 8
},
"EC109": {
"revision": 1,
"explanation": "The symbol shows a temperature-dependent resistor whose resistance falls as temperature rises; that negative temperature coefficient is an NTC thermistor.",
"source": "https://50ohm.de/E_widerstand_ntc_ptc.html",
"confidence": 7
},
"EC110": {
"revision": 1,
"explanation": "An NTC symbol indicates temperature dependence with resistance decreasing as temperature increases. In the shown choices, that is the symbol with the temperature arrow up and resistance/conductance indication downward as described on 50ohm.",
"source": "https://50ohm.de/E_widerstand_ntc_ptc.html",
"confidence": 7
},
"EC111": {
"revision": 1,
"explanation": "A PTC thermistor has a positive temperature coefficient: as temperature rises, resistance rises. The matching symbol is the one with both temperature and resistance trend upward.",
"source": "https://50ohm.de/E_widerstand_ntc_ptc.html",
"confidence": 7
},
"EC112": {
"revision": 1,
"explanation": "A 10 percent tolerance on 5.6 kOhm is 0.56 kOhm. The possible range is 5.6 - 0.56 to 5.6 + 0.56 kOhm, or 5040 to 6160 Ohm.",
"source": "https://50ohm.de/NE_widerstand_toleranz.html",
"confidence": 8
},
"EC113": {
"revision": 1,
"explanation": "Green-blue-red is 56 times 100, so the nominal value is 5600 Ohm. Silver means 10 percent tolerance, giving 5040 to 6160 Ohm.",
"source": "https://50ohm.de/NE_widerstand_toleranz.html",
"confidence": 8
},
"EC114": {
"revision": 1,
"explanation": "Common three-digit SMD resistor marking uses the first digits as significant figures and the last digit as the power of ten multiplier.",
"source": "https://50ohm.de/E_widerstand_smd.html",
"confidence": 8
},
"EC115": {
"revision": 1,
"explanation": "The marking 103 means 10 followed by 3 zeros: 10 * 10^3 Ohm = 10000 Ohm = 10 kOhm.",
"source": "https://50ohm.de/E_widerstand_smd.html",
"confidence": 8
},
"EC116": {
"revision": 1,
"explanation": "The marking 221 means 22 followed by one zero: 22 * 10^1 Ohm = 220 Ohm.",
"source": "https://50ohm.de/E_widerstand_smd.html",
"confidence": 8
},
"EC117": {
"revision": 1,
"explanation": "The marking 223 means 22 followed by three zeros: 22 * 10^3 Ohm = 22000 Ohm = 22 kOhm.",
"source": "https://50ohm.de/E_widerstand_smd.html",
"confidence": 8
},
"EC201": {
"revision": 1,
"explanation": "An initially discharged capacitor charges quickly at first, then the voltage rise flattens as it approaches the supply voltage. That is the rising exponential charging curve.",
"source": "https://50ohm.de/EA_kondensator_1.html",
"confidence": 7
},
"EC202": {
"revision": 1,
"explanation": "A capacitor's AC reactance is inversely proportional to frequency. As frequency increases, an ideal capacitor's opposition to AC decreases.",
"source": "https://50ohm.de/EA_kondensator_1.html",
"confidence": 8
},
"EC203": {
"revision": 1,
"explanation": "For a plate capacitor, capacitance is proportional to plate area and dielectric constant, and inversely proportional to plate spacing. A larger spacing therefore reduces capacitance.",
"source": "https://50ohm.de/EA_kondensator_1.html",
"confidence": 8
},
"EC204": {
"revision": 1,
"explanation": "Increasing the plate distance puts the same plates farther apart, so the plate capacitor's capacitance falls.",
"source": "https://50ohm.de/EA_kondensator_1.html",
"confidence": 8
},
"EC205": {
"revision": 1,
"explanation": "Ideal plate-capacitor capacitance depends on geometry and dielectric material, not on the applied voltage.",
"source": "https://50ohm.de/EA_kondensator_1.html",
"confidence": 8
},
"EC206": {
"revision": 1,
"explanation": "A variable capacitor with rotor plates moving between fixed stator plates is a Drehkondensator; rotation changes the overlapping plate area and thus the capacitance.",
"source": "https://50ohm.de/EA_kondensator_1.html",
"confidence": 8
},
"EC207": {
"revision": 1,
"explanation": "Electrolytic capacitors are polarized because their oxide dielectric depends on the correct DC polarity; reversed polarity can damage them.",
"source": "https://50ohm.de/EA_kondensator_1.html",
"confidence": 8
},
"EC301": {
"revision": 1,
"explanation": "After DC is applied through a resistor, an inductor initially opposes the current change, so the voltage across it starts high and then decays toward zero.",
"source": "https://50ohm.de/EA_spule_1.html",
"confidence": 7
},
"EC302": {
"revision": 1,
"explanation": "The coil initially limits current because it opposes the sudden current change, so the lamp fed through the plain resistor lights first.",
"source": "https://50ohm.de/EA_spule_1.html",
"confidence": 8
},
"EC303": {
"revision": 1,
"explanation": "An ideal inductor's AC reactance is proportional to frequency, so its opposition to AC rises as frequency increases.",
"source": "https://50ohm.de/EA_spule_1.html",
"confidence": 8
},
"EC304": {
"revision": 1,
"explanation": "Any current-carrying conductor has a magnetic field and therefore some inductance, even if it is only a straight piece of wire.",
"source": "https://50ohm.de/E_spule_1.html",
"confidence": 8
},
"EC305": {
"revision": 1,
"explanation": "For the same winding, shortening the coil length increases inductance. Compressing the cylindrical coil in the length direction therefore raises L.",
"source": "https://50ohm.de/EA_spule_1.html",
"confidence": 8
},
"EC306": {
"revision": 1,
"explanation": "For the same turns and cross-section, inductance is inversely proportional to coil length. Doubling the length halves 12 microhenry to 6 microhenry.",
"source": "https://50ohm.de/EA_spule_1.html",
"confidence": 8
},
"EC307": {
"revision": 1,
"explanation": "Inductance is proportional to the square of the number of turns. Doubling the turns multiplies 12 microhenry by 4, giving 48 microhenry.",
"source": "https://50ohm.de/EA_spule_1.html",
"confidence": 8
},
"EC401": {
"revision": 1,
"explanation": "A 15:1 transformer ratio steps the 230 V primary down by 15. 230/15 is about 15.3 V, so the secondary is about 15 V.",
"source": "https://50ohm.de/E_uebertrager_1.html",
"confidence": 8
},
"EC402": {
"revision": 1,
"explanation": "If the primary has five times as many turns as the secondary, the secondary voltage is one fifth of the primary voltage. 230/5 = 46 V.",
"source": "https://50ohm.de/E_uebertrager_1.html",
"confidence": 8
},
"EC403": {
"revision": 1,
"explanation": "Turns ratio follows voltage ratio: 230/11.5 = 20. The secondary therefore has 600/20 = 30 turns.",
"source": "https://50ohm.de/E_uebertrager_1.html",
"confidence": 8
},
"EC404": {
"revision": 1,
"explanation": "The secondary voltage is four times the primary voltage, so the secondary must have four times the turns. 150 * 4 = 600 turns.",
"source": "https://50ohm.de/E_uebertrager_1.html",
"confidence": 8
},
"EC501": {
"revision": 1,
"explanation": "In reverse bias a normal diode blocks current except for a tiny leakage current, so it behaves like a high resistance.",
"source": "https://50ohm.de/EA_diode_1.html",
"confidence": 8
},
"EC502": {
"revision": 1,
"explanation": "A diode conducts mainly in one direction, so it can pass one half-cycle polarity and block the other; that is the basic rectifier function.",
"source": "https://50ohm.de/EA_diode_1.html",
"confidence": 8
},
"EC503": {
"revision": 1,
"explanation": "Germanium diodes have a lower forward threshold, roughly 0.2 to 0.4 V, while silicon diodes are typically around 0.6 to 0.8 V.",
"source": "https://50ohm.de/EA_diode_1.html",
"confidence": 8
},
"EC504": {
"revision": 1,
"explanation": "A Schottky diode uses a metal-semiconductor junction, giving a low forward voltage and very fast switching compared with ordinary pn diodes.",
"source": "https://50ohm.de/EA_diode_1.html",
"confidence": 8
},
"EC505": {
"revision": 1,
"explanation": "On the shown characteristic plot, curve 1 starts conducting at the lowest forward voltage near 0.2 V, which matches a Schottky diode.",
"source": "https://50ohm.de/EA_diode_1.html",
"confidence": 7
},
"EC506": {
"revision": 1,
"explanation": "Curve 2 begins conducting around 0.2 to 0.4 V, the typical forward-threshold range for a germanium diode.",
"source": "https://50ohm.de/EA_diode_1.html",
"confidence": 7
},
"EC507": {
"revision": 1,
"explanation": "Curve 3 starts its steep rise around 0.6 to 0.8 V, matching the usual silicon-diode forward threshold.",
"source": "https://50ohm.de/EA_diode_1.html",
"confidence": 7
},
"EC508": {
"revision": 1,
"explanation": "Curve 4 has the highest forward threshold in the plot, around the LED range, so it represents a light-emitting diode.",
"source": "https://50ohm.de/EA_diode_1.html",
"confidence": 7
},
"EC509": {
"revision": 1,
"explanation": "A silicon diode conducts when its anode is about 0.7 V more positive than its cathode. In the selected drawing, the right/anode side is 1.3 V and the left/cathode side is 0.6 V.",
"source": "https://50ohm.de/EA_diode_1.html",
"confidence": 7
},
"EC510": {
"revision": 1,
"explanation": "Use the silicon-diode rule: anode about 0.7 V above cathode. The selected drawing has 0.3 V on the anode side and -0.4 V on the cathode side.",
"source": "https://50ohm.de/EA_diode_1.html",
"confidence": 7
},
"EC511": {
"revision": 1,
"explanation": "Forward conduction depends on voltage difference, not whether the node voltages are positive. Here the anode is -1.3 V and the cathode is -2.0 V, so the anode is 0.7 V higher.",
"source": "https://50ohm.de/EA_diode_1.html",
"confidence": 7
},
"EC512": {
"revision": 1,
"explanation": "The conducting silicon-diode case is the one with the anode about 0.7 V above the cathode. In the selected drawing, -3.0 V is 0.7 V higher than -3.7 V.",
"source": "https://50ohm.de/EA_diode_1.html",
"confidence": 7
},
"EC513": {
"revision": 1,
"explanation": "A silicon diode becomes forward-biased when the anode is about 0.7 V above the cathode. 5.7 V at the anode and 5.0 V at the cathode meets that condition.",
"source": "https://50ohm.de/EA_diode_1.html",
"confidence": 8
},
"EC514": {
"revision": 1,
"explanation": "The circuit is a current-limited LED: the resistor sets the LED current and the diode symbol with outgoing arrows indicates light emission.",
"source": "https://50ohm.de/EA_diode_1.html",
"confidence": 7
},
"EC515": {
"revision": 1,
"explanation": "The resistor must drop the remaining voltage: 5.0 V - 1.4 V = 3.6 V. At 20 mA, R = 3.6/0.020 = 180 Ohm.",
"source": "https://50ohm.de/EA_diode_1.html",
"confidence": 8
},
"EC516": {
"revision": 1,
"explanation": "The resistor drops 5.5 V - 1.75 V = 3.75 V. With 25 mA, R = 3.75/0.025 = 150 Ohm and P = 3.75 * 0.025 about 0.094 W, so 0.1 W is needed.",
"source": "https://50ohm.de/EA_diode_1.html",
"confidence": 8
},
"EC517": {
"revision": 1,
"explanation": "The bent cathode bar is the distinctive schematic mark for a Zener diode, used in reverse breakdown operation.",
"source": "https://50ohm.de/EA_diode_1.html",
"confidence": 7
},
"EC518": {
"revision": 1,
"explanation": "A Zener diode is designed to operate in reverse breakdown at a defined voltage, making it useful for voltage stabilization.",
"source": "https://50ohm.de/EA_diode_1.html",
"confidence": 8
},
"EC519": {
"revision": 1,
"explanation": "The shown circuit puts a Zener diode across the output after a series resistor, the standard simple shunt voltage stabilizer arrangement.",
"source": "https://50ohm.de/EA_diode_1.html",
"confidence": 7
},
"EC520": {
"revision": 1,
"explanation": "For positive output stabilization, the Zener diode is placed after the series resistor and reverse-biased across the output. That lets it clamp the output near its Zener voltage.",
"source": "https://50ohm.de/EA_diode_1.html",
"confidence": 7
},
"EC521": {
"revision": 1,
"explanation": "The resistor drops 13.8 V - 5 V = 8.8 V at 30 mA. R = 8.8/0.030 = 293 Ohm approximately.",
"source": "https://50ohm.de/EA_diode_1.html",
"confidence": 8
},
"EC522": {
"revision": 1,
"explanation": "The series resistor carries both Zener and load current: 25 mA + 20 mA = 45 mA. With a 4.7 V output, R = (13.8 - 4.7)/0.045 about 202 Ohm.",
"source": "https://50ohm.de/EA_diode_1.html",
"confidence": 8
},
"EC601": {
"revision": 1,
"explanation": "A transistor can be biased to switch fully on/off, to operate linearly as an amplifier, or in some cases to behave as a controllable resistance.",
"source": "https://50ohm.de/NEA_transistor_1.html",
"confidence": 8
},
"EC602": {
"revision": 1,
"explanation": "A transistor is built from semiconductor regions; the usual bipolar types use alternating n- and p-doped semiconductor zones.",
"source": "https://50ohm.de/NEA_transistor_1.html",
"confidence": 8
},
"EC603": {
"revision": 1,
"explanation": "In the practical current-control model, a small base current controls a much larger collector current; their ratio is the current gain.",
"source": "https://50ohm.de/NEA_transistor_1.html",
"confidence": 8
},
"EC604": {
"revision": 1,
"explanation": "Bipolar junction transistors are the NPN and PNP types. FET names such as MOS-FET or junction-FET belong to field-effect transistors, not bipolar transistors.",
"source": "https://50ohm.de/NEA_transistor_1.html",
"confidence": 8
},
"EC605": {
"revision": 2,
"explanation": "A bipolar transistor symbol has base, collector, and emitter terminals, with an emitter arrow; FET symbols use gate, drain, and source structures instead.",
"source": "https://50ohm.de/NEA_slide_nea_bauelemente.html",
"confidence": 7
},
"EC606": {
"revision": 2,
"explanation": "In an NPN transistor symbol the emitter arrow points outward, matching the common mnemonic 'NPN: Not Pointing iN'.",
"source": "https://50ohm.de/NEA_slide_nea_bauelemente.html",
"confidence": 7
},
"EC607": {
"revision": 2,
"explanation": "In a PNP transistor symbol the emitter arrow points inward toward the transistor body; 50ohm gives the mnemonic 'PNP: Pfeil Nach Platte'.",
"source": "https://50ohm.de/NEA_slide_nea_bauelemente.html",
"confidence": 7
},
"EC608": {
"revision": 1,
"explanation": "The three terminals of a bipolar transistor are emitter, base, and collector. Drain, source, and gate are FET terminal names.",
"source": "https://50ohm.de/NEA_transistor_1.html",
"confidence": 8
},
"EC609": {
"revision": 2,
"explanation": "The shown NPN symbol has the collector at terminal 1, the base at terminal 2, and the emitter with the arrow at terminal 3.",
"source": "https://50ohm.de/NEA_slide_nea_bauelemente.html",
"confidence": 7
},
"EC610": {
"revision": 3,
"explanation": "A silicon BJT conducts when its forward-biased base-emitter junction reaches its threshold; for silicon that is about 0.6 to 0.7 V.",
"source": "https://50ohm.de/NEA_slide_nea_bauelemente.html",
"confidence": 8
},
"EC611": {
"revision": 1,
"explanation": "The emitter current is the sum of collector current and base current, so in the conducting state the emitter carries the largest current.",
"source": "https://50ohm.de/NEA_transistor_1.html",
"confidence": 8
},
"EC612": {
"revision": 2,
"explanation": "For an NPN transistor, collector current flows when the base is about 0.6 V above the emitter. The selected drawing has +2.0 V at the base and +1.4 V at the emitter.",
"source": "https://50ohm.de/NEA_slide_nea_bauelemente.html",
"confidence": 7
},
"EC613": {
"revision": 2,
"explanation": "Only the voltage difference matters: for NPN, the base must be about 0.6 V above the emitter. Here -5.6 V is 0.6 V above -6.2 V, so the transistor conducts.",
"source": "https://50ohm.de/NEA_slide_nea_bauelemente.html",
"confidence": 7
},
"EC614": {
"revision": 2,
"explanation": "For a PNP transistor, collector current flows when the base is about 0.6 V below the emitter. The selected drawing has -2.0 V at the base and -1.4 V at the emitter.",
"source": "https://50ohm.de/NEA_slide_nea_bauelemente.html",
"confidence": 7
},
"EC615": {
"revision": 2,
"explanation": "For PNP, the base-emitter voltage is negative when conducting: the base is about 0.6 V lower than the emitter. Here +5.6 V at the base and +6.2 V at the emitter satisfy that.",
"source": "https://50ohm.de/NEA_slide_nea_bauelemente.html",
"confidence": 7
},
"ED101": {
"revision": 1,
"explanation": "In a series voltage divider, voltage drops in the same ratio as resistance. If R1 is 5 times R2, then U1 is 5 times U2.",
"source": "https://50ohm.de/NE_spannungsteiler_1.html",
"confidence": 8
},
"ED102": {
"revision": 1,
"explanation": "In a series voltage divider, U1/U2 = R1/R2. If R1 is one sixth of R2, then U1 is one sixth of U2.",
"source": "https://50ohm.de/NE_spannungsteiler_1.html",
"confidence": 8
},
"ED103": {
"revision": 1,
"explanation": "Use the divider rule: U2 = U * R2/(R1 + R2). With 9 V, 10 kOhm, and 20 kOhm, U2 = 9 * 20/30 = 6.0 V.",
"source": "https://50ohm.de/NE_spannungsteiler_1.html",
"confidence": 8
},
"ED104": {
"revision": 1,
"explanation": "For two parallel resistors, Rg = R1*R2/(R1+R2). 100*400/(100+400) = 40000/500 = 80 Ohm.",
"source": "https://50ohm.de/E_reihe_parallel_widerstand.html",
"confidence": 8
},
"ED105": {
"revision": 1,
"explanation": "For two parallel resistors, Rg = R1*R2/(R1+R2). 50*200/(50+200) = 10000/250 = 40 Ohm.",
"source": "https://50ohm.de/E_reihe_parallel_widerstand.html",
"confidence": 8
},
"ED106": {
"revision": 1,
"explanation": "For n equal resistors in parallel, Rg = R/n. Therefore each resistor is R = n*Rg = 3*1.7 kOhm = 5.1 kOhm.",
"source": "https://50ohm.de/E_reihe_parallel_widerstand.html",
"confidence": 8
},
"ED107": {
"revision": 1,
"explanation": "With three equal resistors, the allowed total power is the sum of the individual ratings when the load is shared. That gives 3*1 W = 3 W in both series and parallel arrangements.",
"source": "https://50ohm.de/E_reihe_parallel_widerstand.html",
"confidence": 8
},
"ED108": {
"revision": 1,
"explanation": "R1 and R2 are in series, giving 500 + 500 = 1000 Ohm. That 1000 Ohm branch is in parallel with R3 = 1000 Ohm, so the total is 500 Ohm.",
"source": "https://50ohm.de/E_reihe_parallel_widerstand.html",
"confidence": 7
},
"ED109": {
"revision": 1,
"explanation": "R1 and R2 first add in series: 500 Ohm + 1.5 kOhm = 2 kOhm. That is in parallel with R3 = 2 kOhm, so the result is 1 kOhm.",
"source": "https://50ohm.de/E_reihe_parallel_widerstand.html",
"confidence": 7
},
"ED110": {
"revision": 1,
"explanation": "The two 1 kOhm resistors are parallel, so they reduce to 500 Ohm. In series with the remaining 500 Ohm, the total is 1 kOhm.",
"source": "https://50ohm.de/E_reihe_parallel_widerstand.html",
"confidence": 7
},
"ED111": {
"revision": 1,
"explanation": "R2 and R3 are both 2 kOhm in parallel, giving 1 kOhm. Adding the series R1 of 1 kOhm gives 2 kOhm total.",
"source": "https://50ohm.de/E_reihe_parallel_widerstand.html",
"confidence": 7
},
"ED112": {
"revision": 1,
"explanation": "R2 and R3 are parallel: 3 kOhm || 1.5 kOhm = 1 kOhm. Add the series R1 of 1 kOhm to get 2 kOhm.",
"source": "https://50ohm.de/E_reihe_parallel_widerstand.html",
"confidence": 7
},
"ED113": {
"revision": 1,
"explanation": "R1, R2, and R3 are parallel: 10 kOhm || 2.5 kOhm || 500 Ohm = 400 Ohm. Adding the series 600 Ohm resistor gives 1 kOhm.",
"source": "https://50ohm.de/E_reihe_parallel_widerstand.html",
"confidence": 7
},
"ED114": {
"revision": 1,
"explanation": "Reduce the obvious groups step by step: 50 Ohm + 50 Ohm gives 100 Ohm, 100 Ohm in parallel with 100 Ohm gives 50 Ohm, then the remaining series parts total 250 Ohm.",
"source": "https://50ohm.de/NE_reihe_parallel_widerstandsnetz_1.html",
"confidence": 7
},
"ED115": {
"revision": 1,
"explanation": "Combine the clear series and parallel subgroups in stages; the network reduces to a final series sum of 550 Ohm.",
"source": "https://50ohm.de/NE_reihe_parallel_widerstandsnetz_1.html",
"confidence": 7
},
"ED116": {
"revision": 1,
"explanation": "After reducing the drawn subgroups, the remaining series values are 400 Ohm, 200 Ohm, 200 Ohm, and 150 Ohm. Their sum is 950 Ohm.",
"source": "https://50ohm.de/NE_reihe_parallel_widerstandsnetz_1.html",
"confidence": 7
},
"ED117": {
"revision": 1,
"explanation": "Parallel capacitances add directly. 0.1 uF = 100 nF and 50000 pF = 50 nF, so 100 + 150 + 50 = 300 nF = 0.3 uF.",
"source": "https://50ohm.de/NEA_reihe_parallel_kondensator.html",
"confidence": 8
},
"ED118": {
"revision": 1,
"explanation": "Parallel capacitors add directly after unit conversion: 22 nF + 0.033 uF (33 nF) + 15000 pF (15 nF) = 70 nF = 0.070 uF.",
"source": "https://50ohm.de/NEA_reihe_parallel_kondensator.html",
"confidence": 8
},
"ED119": {
"revision": 1,
"explanation": "For equal capacitors in series, Cg = C/n. Three 0.33 uF capacitors therefore give 0.33/3 = 0.110 uF.",
"source": "https://50ohm.de/NEA_reihe_parallel_kondensator.html",
"confidence": 8
},
"ED120": {
"revision": 1,
"explanation": "Convert 200000 nF to 200 uF. The series formula gives 1/Cg = 1/100 + 1/200 + 1/200, so Cg = 50 uF.",
"source": "https://50ohm.de/NEA_reihe_parallel_kondensator.html",
"confidence": 8
},
"ED121": {
"revision": 1,
"explanation": "C1 and C2 are equal 10 nF capacitors in series, so their equivalent is 5 nF. In parallel with C3 = 5 nF, the total is 10 nF.",
"source": "https://50ohm.de/NEA_reihe_parallel_kondensator.html",
"confidence": 7
},
"ED122": {
"revision": 1,
"explanation": "C2 and C3 are parallel, giving 1 uF + 1 uF = 2 uF. That is in series with C1 = 2 uF, so two equal 2 uF capacitors in series give 1.0 uF.",
"source": "https://50ohm.de/NEA_reihe_parallel_kondensator.html",
"confidence": 7
},
"ED123": {
"revision": 1,
"explanation": "C2 and C3 are parallel, so 4 nF + 4 nF = 8 nF. That 8 nF equivalent is in series with C1 = 8 nF, giving 4 nF.",
"source": "https://50ohm.de/NEA_reihe_parallel_kondensator.html",
"confidence": 7
},
"ED124": {
"revision": 1,
"explanation": "Convert C3 = 100000 pF to 100 nF. C2 and C3 are parallel, giving 200 nF; that is in series with C1 = 200 nF, so the total is 100 nF.",
"source": "https://50ohm.de/NEA_reihe_parallel_kondensator.html",
"confidence": 7
},
"ED201": {
"revision": 1,
"explanation": "The graph passes low frequencies and attenuates frequencies above the cutoff, which is the defining response of a low-pass filter.",
"source": "https://50ohm.de/EA_schwingkreis_1.html",
"confidence": 7
},
"ED202": {
"revision": 1,
"explanation": "The graph attenuates low frequencies and passes higher frequencies after the cutoff, so it is a high-pass response.",
"source": "https://50ohm.de/EA_schwingkreis_1.html",
"confidence": 7
},
"ED203": {
"revision": 1,
"explanation": "The curve passes only a middle frequency range and attenuates both low and high frequencies, which is a band-pass response.",
"source": "https://50ohm.de/EA_schwingkreis_1.html",
"confidence": 7
},
"ED204": {
"revision": 1,
"explanation": "The curve passes frequencies on both sides but rejects a middle range around resonance, so it is a band-stop response.",
"source": "https://50ohm.de/EA_schwingkreis_1.html",
"confidence": 7
},
"ED205": {
"revision": 1,
"explanation": "A series resonant circuit has minimum impedance at resonance because inductive and capacitive reactance cancel, giving the V-shaped impedance curve.",
"source": "https://50ohm.de/EA_schwingkreis_1.html",
"confidence": 8
},
"ED206": {
"revision": 1,
"explanation": "A parallel resonant circuit has maximum impedance at resonance, producing the peaked impedance curve shown.",
"source": "https://50ohm.de/EA_schwingkreis_1.html",
"confidence": 8
},
"ED207": {
"revision": 1,
"explanation": "At resonance a parallel LC circuit presents a very high impedance; away from resonance one branch becomes comparatively low impedance.",
"source": "https://50ohm.de/EA_schwingkreis_1.html",
"confidence": 8
},
"ED208": {
"revision": 1,
"explanation": "The circuit takes the output after a series resistor with a capacitor shunting high frequencies to ground, so low frequencies pass and high frequencies are attenuated: a low-pass filter.",
"source": "https://50ohm.de/EA_schwingkreis_1.html",
"confidence": 7
},
"ED209": {
"revision": 1,
"explanation": "A series inductor followed by a shunt capacitor passes low frequencies: the inductor is low impedance at low frequency and the capacitor shunts high frequency components.",
"source": "https://50ohm.de/EA_schwingkreis_1.html",
"confidence": 7
},
"ED210": {
"revision": 1,
"explanation": "For microphone audio low-pass filtering, the selected RC network uses capacitors to bypass high-frequency components while the wanted lower audio range remains at the output.",
"source": "https://50ohm.de/EA_schwingkreis_1.html",
"confidence": 7
},
"ED211": {
"revision": 1,
"explanation": "A series capacitor followed by a resistor load is a high-pass: the capacitor blocks low-frequency components and passes higher-frequency components more easily.",
"source": "https://50ohm.de/EA_schwingkreis_1.html",
"confidence": 7
},
"ED212": {
"revision": 1,
"explanation": "With a series capacitor and a shunt inductor, low frequencies are shunted through the inductor while higher frequencies pass through the capacitor path, so the circuit is a high-pass.",
"source": "https://50ohm.de/EA_schwingkreis_1.html",
"confidence": 7
},
"ED213": {
"revision": 1,
"explanation": "The selected LC ladder has a series capacitor path with shunt inductors, the high-pass pattern: low frequencies are bypassed, higher frequencies are passed.",
"source": "https://50ohm.de/EA_schwingkreis_1.html",
"confidence": 7
},
"ED214": {
"revision": 1,
"explanation": "A parallel resonant circuit placed in series with the signal path has high impedance at resonance and blocks that frequency, so it is a Sperrkreis.",
"source": "https://50ohm.de/EA_schwingkreis_1.html",
"confidence": 7
},
"ED215": {
"revision": 1,
"explanation": "A series resonant LC branch connected across the signal path has low impedance at resonance and diverts that frequency away from the output, so it is a Saugkreis.",
"source": "https://50ohm.de/EA_schwingkreis_1.html",
"confidence": 7
},
"ED216": {
"revision": 1,
"explanation": "HF filters need low-loss, high-Q capacitors with small parasitic effects; ceramic and air capacitors are preferred over electrolytics.",
"source": "https://50ohm.de/EA_kondensator_1.html",
"confidence": 8
},
"ED301": {
"revision": 1,
"explanation": "A useful DC supply should keep its output voltage nearly constant under load; otherwise the connected radio stages see supply-voltage changes.",
"source": "https://50ohm.de/EA_spannungsquelle.html",
"confidence": 8
},
"ED302": {
"revision": 1,
"explanation": "Switch-mode supplies convert power at high switching frequency, allowing small transformers and heat sinks, so they are efficient, light, and compact.",
"source": "https://50ohm.de/NEA_schaltnetzteil_1.html",
"confidence": 8
},
"ED303": {
"revision": 1,
"explanation": "The high-frequency switching action can generate RF interference unless the supply is well filtered and shielded.",
"source": "https://50ohm.de/NEA_schaltnetzteil_1.html",
"confidence": 8
},
"ED304": {
"revision": 1,
"explanation": "The circuit is a single-diode half-wave rectifier. The load voltage contains only the conducting half-cycles, with the opposite half-cycles blocked by the diode.",
"source": "https://50ohm.de/EA_gleichrichter_1.html",
"confidence": 7
},
"ED401": {
"revision": 1,
"explanation": "Power gain means the output signal power is greater than the input signal power. That extra power must come from an external supply, not from the input signal alone.",
"source": "https://50ohm.de/NE_verstaerker.html",
"confidence": 8
},
"ED402": {
"revision": 1,
"explanation": "The shown transistor audio-stage topology is an NF amplifier; it is meant for low-frequency/audio signal amplification, not RF or IF selection.",
"source": "https://50ohm.de/NE_verstaerker.html",
"confidence": 7
},
"ED403": {
"revision": 1,
"explanation": "An HF power amplifier raises the transmitter's RF signal level to the desired output power before feeding the antenna system.",
"source": "https://50ohm.de/NE_verstaerker.html",
"confidence": 8
},
"ED501": {
"revision": 1,
"explanation": "An LC oscillator uses a tuned circuit made from an inductor L and capacitor C; that resonant circuit sets the oscillation frequency.",
"source": "https://50ohm.de/E_oszillatoren.html",
"confidence": 8
},
"ED502": {
"revision": 1,
"explanation": "The LC resonance frequency is inversely related to the square root of capacitance. If C increases, the oscillator frequency decreases.",
"source": "https://50ohm.de/E_oszillatoren.html",
"confidence": 8
},
"ED503": {
"revision": 1,
"explanation": "The LC resonance frequency rises when capacitance falls, because frequency is inversely related to sqrt(L*C).",
"source": "https://50ohm.de/E_oszillatoren.html",
"confidence": 8
},
"ED504": {
"revision": 1,
"explanation": "The LC resonance frequency is inversely related to the square root of inductance. If L increases, the oscillator frequency decreases.",
"source": "https://50ohm.de/E_oszillatoren.html",
"confidence": 8
},
"ED505": {
"revision": 1,
"explanation": "When inductance decreases, the LC product becomes smaller, so the resonant frequency becomes higher.",
"source": "https://50ohm.de/E_oszillatoren.html",
"confidence": 8
},
"ED506": {
"revision": 1,
"explanation": "In a crystal oscillator, the quartz crystal is the frequency-determining resonator.",
"source": "https://50ohm.de/E_oszillatoren.html",
"confidence": 8
},
"ED507": {
"revision": 1,
"explanation": "A quartz crystal's resonance changes much less with temperature and component tolerances than a simple LC circuit, so crystal oscillators are more frequency-stable.",
"source": "https://50ohm.de/E_oszillatoren.html",
"confidence": 8
},
"EE101": {
"revision": 1,
"explanation": "An unmodulated carrier is a steady sine wave with constant amplitude, frequency, and phase; the selected diagram shows that unchanged carrier.",
"source": "https://50ohm.de/E_unmodulierter_traeger.html",
"confidence": 7
},
"EE201": {
"revision": 1,
"explanation": "AM carries both sidebands plus carrier, while SSB suppresses the carrier and one sideband. Therefore SSB needs less than half the bandwidth of AM.",
"source": "https://50ohm.de/E_ssb_2.html",
"confidence": 8
},
"EE202": {
"revision": 1,
"explanation": "In SSB, only one translated sideband is transmitted, so the occupied RF bandwidth is essentially the same as the audio/NF bandwidth being sent.",
"source": "https://50ohm.de/E_ssb_2.html",
"confidence": 8
},
"EE203": {
"revision": 1,
"explanation": "USB places the audio component above the carrier. 21.250 MHz + 0.001 MHz = 21.251 MHz.",
"source": "https://50ohm.de/E_ssb_2.html",
"confidence": 8
},
"EE204": {
"revision": 1,
"explanation": "LSB places the audio component below the carrier and suppresses the carrier in ideal SSB. 3.650 MHz - 0.002 MHz = 3.648 MHz.",
"source": "https://50ohm.de/E_ssb_2.html",
"confidence": 8
},
"EE205": {
"revision": 2,
"explanation": "For SSB voice, RF output follows the audio drive level. Reducing the NF/audio amplitude reduces the modulated transmitter output power.",
"source": "https://50ohm.de/E_slide_e_modulation.html",
"confidence": 8
},
"EE206": {
"revision": 2,
"explanation": "Too little microphone gain gives too little audio drive to the SSB modulator, so the transmitter produces low output power.",
"source": "https://50ohm.de/E_slide_e_modulation.html",
"confidence": 8
},
"EE207": {
"revision": 1,
"explanation": "CW keys one carrier rather than transmitting a full speech spectrum, so its occupied bandwidth is smaller than both SSB voice and AM voice.",
"source": "https://50ohm.de/E_ssb_2.html",
"confidence": 8
},
"EE301": {
"revision": 1,
"explanation": "The shown waveform keeps amplitude essentially constant while the instantaneous carrier frequency changes, which identifies frequency modulation.",
"source": "https://50ohm.de/EA_fm_2.html",
"confidence": 7
},
"EE302": {
"revision": 1,
"explanation": "FM carries information in frequency deviation rather than amplitude, so amplitude noise has less direct effect than it does in SSB.",
"source": "https://50ohm.de/EA_fm_2.html",
"confidence": 8
},
"EE303": {
"revision": 1,
"explanation": "Vehicle electrical noise often appears as amplitude disturbance. FM is least affected because the receiver can limit amplitude and use frequency deviation instead.",
"source": "https://50ohm.de/EA_fm_2.html",
"confidence": 8
},
"EE304": {
"revision": 1,
"explanation": "In FM, a larger frequency deviation spreads the signal over a wider range of frequencies, increasing RF bandwidth.",
"source": "https://50ohm.de/EA_fm_2.html",
"confidence": 8
},
"EE305": {
"revision": 1,
"explanation": "Excessive FM bandwidth is reduced by lowering the deviation setting, because deviation directly determines how far the carrier moves from center frequency.",
"source": "https://50ohm.de/EA_fm_2.html",
"confidence": 8
},
"EE306": {
"revision": 1,
"explanation": "In FM, loudness is represented by the size of the carrier-frequency deviation, not by RF amplitude.",
"source": "https://50ohm.de/EA_fm_2.html",
"confidence": 8
},
"EE401": {
"revision": 1,
"explanation": "Bandwidth is occupied frequency range measured in hertz. Data rate is the amount of information transferred per time, measured in bit/s.",
"source": "https://50ohm.de/NEA_datenuebertragungsdrate.html",
"confidence": 8
},
"EE402": {
"revision": 1,
"explanation": "SSB translates the audio-frequency digimode signal to RF while preserving its narrow bandwidth, which is why modes such as FT8 or BPSK31 are sent through an SSB transmitter path.",
"source": "https://50ohm.de/NEA_digimode_ssb.html",
"confidence": 8
},
"EE403": {
"revision": 1,
"explanation": "With SSB, the RF bandwidth follows the bandwidth of the audio/NF signal. A 50 Hz audio signal therefore occupies about 50 Hz RF bandwidth.",
"source": "https://50ohm.de/NEA_digimode_ssb.html",
"confidence": 8
},
"EE404": {
"revision": 1,
"explanation": "A 2.4 kHz SSB passband can contain several much narrower digimode signals at different audio frequencies, and software can decode one or more of them.",
"source": "https://50ohm.de/NEA_digimode_ssb.html",
"confidence": 8
},
"EE405": {
"revision": 2,
"explanation": "Reporter networks collect received digimode spots by callsign. Sending a suitable signal such as WSPR and then searching the reporting platform shows where it was received.",
"source": "https://50ohm.de/NEA_slide_nea_digitale_uebertragungsverfahren.html",
"confidence": 8
},
"EE406": {
"revision": 1,
"explanation": "ASK changes the carrier amplitude between symbol states while frequency stays recognisably the same; the selected diagram shows those amplitude changes.",
"source": "https://50ohm.de/EA_ask_fsk_afsk.html",
"confidence": 7
},
"EE407": {
"revision": 1,
"explanation": "FSK changes between different carrier frequencies while keeping amplitude essentially constant; the selected diagram shows changing period/frequency.",
"source": "https://50ohm.de/EA_ask_fsk_afsk.html",
"confidence": 7
},
"EE408": {
"revision": 1,
"explanation": "In AFSK, frequency-shift keying is first generated as an audio-frequency signal, which then modulates an RF transmitter such as an FM, AM, or SSB rig.",
"source": "https://50ohm.de/NEA_afsk.html",
"confidence": 8
},
"EE409": {
"revision": 2,
"explanation": "TDMA separates users by time slots: signals take rapid turns on the same frequency rather than transmitting continuously at once.",
"source": "https://50ohm.de/NEA_vielfachzugriff.html",
"confidence": 8
},
"EE410": {
"revision": 2,
"explanation": "FDMA separates simultaneous signals by frequency, so users transmit at the same time but on different frequency channels.",
"source": "https://50ohm.de/NEA_vielfachzugriff.html",
"confidence": 8
},
"EE411": {
"revision": 2,
"explanation": "CDMA lets signals share time and frequency by applying different spreading codes that the receiver uses to separate them.",
"source": "https://50ohm.de/NEA_vielfachzugriff.html",
"confidence": 8
},
"EE412": {
"revision": 1,
"explanation": "In a packet-switched network, packets can be forwarded through intermediate stations or routers when the two endpoints cannot reach each other directly.",
"source": "https://50ohm.de/NEA_paketvermittelte_netzwerke.html",
"confidence": 8
},
"EE413": {
"revision": 1,
"explanation": "The IP address plus subnet mask defines which addresses are on the same local subnet and are reachable directly without routing.",
"source": "https://50ohm.de/NEA_paketvermittelte_netzwerke.html",
"confidence": 8
},
"EE414": {
"revision": 1,
"explanation": "IP is a network protocol, not something limited to the public Internet, so it can also be used in amateur-radio networks such as HAMNET.",
"source": "https://50ohm.de/NEA_paketvermittelte_netzwerke.html",
"confidence": 8
},
"EE415": {
"revision": 1,
"explanation": "SSTV sends still pictures slowly, while ATV is amateur television with moving pictures and much larger bandwidth needs.",
"source": "https://50ohm.de/NEA_digimode_ssb.html",
"confidence": 8
},
"EF101": {
"revision": 1,
"explanation": "The circuit is a detector receiver: the tuned circuit selects the station and the diode recovers the audio envelope without an active oscillator or amplifier.",
"source": "https://50ohm.de/NE_detektorempf%C3%A4nger.html",
"confidence": 7
},
"EF102": {
"revision": 1,
"explanation": "A superhet converts received signals to a fixed IF, so fixed filters can provide much better selectivity than a tuned-radio-frequency receiver.",
"source": "https://50ohm.de/E_ueberlagerungsempfaenger_einfachsuper_1.html",
"confidence": 8
},
"EF201": {
"revision": 1,
"explanation": "A mixer mainly produces the sum and absolute difference: 31.7 MHz + 21 MHz = 52.7 MHz and |31.7 MHz - 21 MHz| = 10.7 MHz.",
"source": "https://50ohm.de/E_mischer.html",
"confidence": 8
},
"EF202": {
"revision": 1,
"explanation": "Mixer products are the sum and absolute difference: 38.7 MHz + 28 MHz = 66.7 MHz and |38.7 MHz - 28 MHz| = 10.7 MHz.",
"source": "https://50ohm.de/E_mischer.html",
"confidence": 8
},
"EF203": {
"revision": 1,
"explanation": "The desired mixer products are sum and difference, so 30 MHz and 39 MHz produce 69 MHz and 9 MHz.",
"source": "https://50ohm.de/E_mischer.html",
"confidence": 8
},
"EF204": {
"revision": 1,
"explanation": "A mixer gives sum and absolute difference: 145 MHz + 136 MHz = 281 MHz and |145 MHz - 136 MHz| = 9 MHz.",
"source": "https://50ohm.de/E_mischer.html",
"confidence": 8
},
"EF205": {
"revision": 1,
"explanation": "The wanted first-order mixer products are the sum and difference, here 281 MHz and 9 MHz.",
"source": "https://50ohm.de/E_mischer.html",
"confidence": 8
},
"EF206": {
"revision": 1,
"explanation": "Mixers generate many RF products, so good shielding is needed to keep unwanted signals from being radiated or coupled into other stages.",
"source": "https://50ohm.de/E_mischer.html",
"confidence": 8
},
"EF207": {
"revision": 1,
"explanation": "An oscillator should be enclosed in a grounded metal shield so its RF energy is not unintentionally radiated.",
"source": "https://50ohm.de/NE_oszillatoren.html",
"confidence": 8
},
"EF208": {
"revision": 1,
"explanation": "In direct conversion the IF is audio, so the local oscillator must be very close to the received RF frequency.",
"source": "https://50ohm.de/E_ueberlagerungsempfaenger_einfachsuper_1.html",
"confidence": 8
},
"EF209": {
"revision": 1,
"explanation": "A BFO inserts the missing carrier needed to demodulate CW or SSB, making those signals audible.",
"source": "https://50ohm.de/NEA_bfo_1.html",
"confidence": 8
},
"EF210": {
"revision": 1,
"explanation": "Narrow receiver bandwidth rejects nearby unwanted signals, which is exactly high selectivity.",
"source": "https://50ohm.de/E_trennschaerfe_1.html",
"confidence": 8
},
"EF211": {
"revision": 1,
"explanation": "AGC changes receiver gain as the RF input varies, keeping the demodulated audio level more constant.",
"source": "https://50ohm.de/NE_agc_1.html",
"confidence": 8
},
"EF212": {
"revision": 1,
"explanation": "AGC stands for Automatic Gain Control, the automatic receiver gain regulation used to reduce level swings.",
"source": "https://50ohm.de/NE_agc_1.html",
"confidence": 8
},
"EF213": {
"revision": 1,
"explanation": "Noise Reduction tries to distinguish wanted signal from noise and suppress the noise component in the received signal.",
"source": "https://50ohm.de/NE_noise_reduction.html",
"confidence": 8
},
"EF214": {
"revision": 1,
"explanation": "A noise blanker blanks short impulse disturbances, unlike a notch filter or AGC which target different problems.",
"source": "https://50ohm.de/NE_noise_reduction.html",
"confidence": 8
},
"EF215": {
"revision": 1,
"explanation": "A notch filter is a narrow rejection filter, so it can suppress interference at one small frequency range while leaving the rest mostly unchanged.",
"source": "https://50ohm.de/NE_notchfilter.html",
"confidence": 8
},
"EF216": {
"revision": 1,
"explanation": "A notch response is recognized by a narrow dip in an otherwise passed band; the correct diagram shows that sharp rejection notch.",
"source": "https://50ohm.de/NE_notchfilter.html",
"confidence": 7
},
"EF217": {
"revision": 1,
"explanation": "An attenuator reduces the RF input level before the receiver front end, preventing overload from strong signals.",
"source": "https://50ohm.de/NE_vorverstaerker_daempfungsglied.html",
"confidence": 8
},
"EF218": {
"revision": 1,
"explanation": "A UHF preamplifier should be at the antenna so it amplifies the signal before feed-line loss degrades the noise figure.",
"source": "https://50ohm.de/NE_vorverstaerker_daempfungsglied.html",
"confidence": 8
},
"EF219": {
"revision": 1,
"explanation": "A 9600-port bypasses audio filtering and takes receive data directly after the FM demodulator, which is point 4 in the shown chain.",
"source": "https://50ohm.de/NEA_9600_port.html",
"confidence": 7
},
"EF301": {
"revision": 1,
"explanation": "The multiplier chain is reversed by division: 145.2 MHz / 2 / 3 / 2 = 12.1 MHz.",
"source": "https://50ohm.de/NE_frequenzvervielfacher_1.html",
"confidence": 8
},
"EF302": {
"revision": 1,
"explanation": "Work backward through the multipliers in the diagram: 21.360 MHz / 3 / 2 = 3.560 MHz.",
"source": "https://50ohm.de/NE_frequenzvervielfacher_1.html",
"confidence": 8
},
"EF303": {
"revision": 1,
"explanation": "Work forward through the multiplier chain: 3.51 MHz x 2 x 2 = 14.04 MHz at output a.",
"source": "https://50ohm.de/NE_frequenzvervielfacher_1.html",
"confidence": 8
},
"EF304": {
"revision": 1,
"explanation": "Temperature changes alter oscillator L/C values gradually, so a VFO under changing temperature slowly drifts in frequency.",
"source": "https://50ohm.de/NE_oszillatoren.html",
"confidence": 8
},
"EF305": {
"revision": 1,
"explanation": "ALC protects the transmit chain from overdrive by reducing the signal amplitude before the power amplifier when level is too high.",
"source": "https://50ohm.de/NEA_alc.html",
"confidence": 8
},
"EF306": {
"revision": 2,
"explanation": "A dynamic compressor raises quiet speech parts relative to loud ones, compressing the speech dynamic range.",
"source": "https://50ohm.de/NE_slide_ne_modulation.html",
"confidence": 8
},
"EF307": {
"revision": 1,
"explanation": "A speech microphone amplifier should pass roughly 300 Hz to 3 kHz and reject lower and higher frequencies, matching the band-pass graph.",
"source": "https://50ohm.de/NE_verstaerker.html",
"confidence": 7
},
"EF308": {
"revision": 1,
"explanation": "Intelligible SSB speech needs only about 2.5 to 3 kHz of audio bandwidth, so about 2.5 kHz is the minimum matching answer.",
"source": "https://50ohm.de/NE_verstaerker.html",
"confidence": 8
},
"EF309": {
"revision": 1,
"explanation": "For 9600-baud FM data the signal should bypass speech audio filters and enter directly at the FM modulator, point 2 in the transmitter diagram.",
"source": "https://50ohm.de/NEA_9600_port.html",
"confidence": 7
},
"EF310": {
"revision": 1,
"explanation": "An SSB speech filter only needs the voice sideband width; practical SSB generation commonly uses about 2.4 kHz.",
"source": "https://50ohm.de/E_ssb_2.html",
"confidence": 8
},
"EF401": {
"revision": 1,
"explanation": "Transmitter output power is measured directly at the transmitter output before tuners, filters, feed lines, or other accessories change it.",
"source": "https://50ohm.de/E_senderausgangsleistung.html",
"confidence": 8
},
"EF402": {
"revision": 1,
"explanation": "For SSB the relevant PEP is measured at the transmitter output using a steady one- or two-tone drive, not with an unmodulated carrier at the antenna.",
"source": "https://50ohm.de/E_senderausgangsleistung.html",
"confidence": 8
},
"EF403": {
"revision": 1,
"explanation": "SSB carries information in signal amplitude and phase, so its final stage must be linear to avoid distorting the waveform.",
"source": "https://50ohm.de/EA_verstaerker.html",
"confidence": 8
},
"EF404": {
"revision": 1,
"explanation": "Changing the final amplifier bias can change linearity, so the transmitter must then be checked for harmonic output.",
"source": "https://50ohm.de/NE_unerwuenschte_aussendungen_2.html",
"confidence": 8
},
"EF405": {
"revision": 1,
"explanation": "The transmitter supply should be well decoupled against RF so RF energy cannot couple into the power wiring or other stages.",
"source": "https://50ohm.de/EA_verstaerker.html",
"confidence": 8
},
"EF501": {
"revision": 1,
"explanation": "A transverter converts both directions: on receive it downconverts the higher band to the transceiver band, and on transmit it upconverts the transceiver signal.",
"source": "https://50ohm.de/NE_transverter_1.html",
"confidence": 8
},
"EF502": {
"revision": 1,
"explanation": "A transverter changes bands by mixing the input signal with a local oscillator and filtering the wanted product.",
"source": "https://50ohm.de/NE_transverter_1.html",
"confidence": 8
},
"EF503": {
"revision": 1,
"explanation": "The block diagram shows receive and transmit frequency conversion around a VHF transceiver, which is a transverter for the 2 m band.",
"source": "https://50ohm.de/NE_transverter_1.html",
"confidence": 7
},
"EF504": {
"revision": 1,
"explanation": "The diagram upconverts a VHF transmit signal to the 13 cm range, so it is a 13 cm converter placed before a VHF transmitter.",
"source": "https://50ohm.de/NE_transverter_1.html",
"confidence": 7
},
"EF505": {
"revision": 1,
"explanation": "In a GHz transverter the oscillator is multiplied, so any oscillator frequency error is multiplied too and can be too large for SSB satellite operation.",
"source": "https://50ohm.de/NE_transverter_1.html",
"confidence": 8
},
"EF601": {
"revision": 1,
"explanation": "Digital signal processing first converts the analog input with an A/D converter and later reconstructs an analog output with a D/A converter.",
"source": "https://50ohm.de/NEA_digitale_signalverarbeitung_einleitung.html",
"confidence": 8
},
"EF602": {
"revision": 1,
"explanation": "A digital filter can only process digital samples, so the analog input signal must first be digitized by A/D conversion.",
"source": "https://50ohm.de/NEA_digitale_signalverarbeitung_einleitung.html",
"confidence": 8
},
"EF603": {
"revision": 1,
"explanation": "SDR means Software Defined Radio: at least part of the receiver or transceiver signal processing is implemented in software.",
"source": "https://50ohm.de/NEA_digitale_signalverarbeitung_einleitung.html",
"confidence": 8
},
"EG101": {
"revision": 1,
"explanation": "A loop made from three equal wire sections forms a triangle, so it is the delta-loop form of a full-wave loop antenna.",
"source": "https://50ohm.de/EA_antennenformen_2.html",
"confidence": 8
},
"EG102": {
"revision": 1,
"explanation": "A wire antenna can have many lengths if an appropriate matching network is used; resonance and feed impedance change with length.",
"source": "https://50ohm.de/NE_antenne_laenge_resonanz.html",
"confidence": 8
},
"EG103": {
"revision": 1,
"explanation": "The diagram shows a wire fed from one end through a simple matching unit, which is an end-fed antenna with a basic matching network.",
"source": "https://50ohm.de/E_antennenformen_2.html",
"confidence": 7
},
"EG104": {
"revision": 1,
"explanation": "The shown end-fed wire with a tuned Fuchs matching circuit is the characteristic Fuchs antenna arrangement.",
"source": "https://50ohm.de/E_antennenformen_2.html",
"confidence": 7
},
"EG105": {
"revision": 1,
"explanation": "A magnetic loop is small compared with wavelength, about lambda/10 circumference, and its near field is dominated by a strong magnetic component.",
"source": "https://50ohm.de/EA_antennenformen_2.html",
"confidence": 8
},
"EG106": {
"revision": 1,
"explanation": "Common HF transmitting antennas include long wire, Yagi-Uda, dipole, Windom, and delta-loop; horn, patch, and parabolic antennas are mainly higher-frequency forms.",
"source": "https://50ohm.de/EA_antennenformen_2.html",
"confidence": 8
},
"EG107": {
"revision": 2,
"explanation": "For 80 m HF operation, dipoles, delta loops, and W3DZZ trap dipoles are practical wire antennas; parabolic, cross-Yagi, and trap-sleeve forms are not suitable choices here.",
"source": "https://50ohm.de/NE_slide_ne_antennen_uebertragungsleitungen.html",
"confidence": 8
},
"EG108": {
"revision": 1,
"explanation": "A 5/8-wave vertical is chosen because its length gives better antenna gain than a quarter-wave mobile vertical.",
"source": "https://50ohm.de/E_antennenformen_2.html",
"confidence": 8
},
"EG109": {
"revision": 1,
"explanation": "The wavelength is 300 / 28.5 = 10.53 m, and 5/8 of that is about 6.58 m.",
"source": "https://50ohm.de/NE_antenne_laenge_resonanz.html",
"confidence": 8
},
"EG110": {
"revision": 1,
"explanation": "A folded dipole is essentially a flattened full-wave loop, so the total wire length is one wavelength.",
"source": "https://50ohm.de/NE_antenne_laenge_resonanz.html",
"confidence": 8
},
"EG111": {
"revision": 1,
"explanation": "A simple Yagi-Uda has the longer reflector behind the driven element and a shorter director in front, giving the order reflector, driven element, director.",
"source": "https://50ohm.de/NE_yagi_uda_2.html",
"confidence": 7
},
"EG112": {
"revision": 2,
"explanation": "For a directional HF antenna, placing it high and far from neighboring equipment reduces field strength at the neighbor and therefore coupling risk.",
"source": "https://50ohm.de/NE_slide_ne_antennen_uebertragungsleitungen.html",
"confidence": 8
},
"EG113": {
"revision": 1,
"explanation": "Microwave dish antennas use a paraboloid reflector plus a feed antenna; the feed illuminates the reflector that forms the narrow beam.",
"source": "https://50ohm.de/EA_parabolspiegel_1.html",
"confidence": 8
},
"EG114": {
"revision": 1,
"explanation": "Dish gain improves when the reflector is many wavelengths across; at least about five wavelengths is the suitable choice for high gain.",
"source": "https://50ohm.de/EA_parabolspiegel_1.html",
"confidence": 8
},
"EG201": {
"revision": 1,
"explanation": "The shortening factor compares wave speed on the line or wire with wave speed in vacuum, so it is the velocity ratio.",
"source": "https://50ohm.de/E_verkuerzungsfaktor_1.html",
"confidence": 8
},
"EG202": {
"revision": 1,
"explanation": "For wire antennas the usual shortening correction is about 0.95, meaning about 95 percent of the free-space calculated length.",
"source": "https://50ohm.de/E_verkuerzungsfaktor_1.html",
"confidence": 8
},
"EG203": {
"revision": 1,
"explanation": "At a dipole end charge and voltage are high while current goes to zero, so the ends are voltage maxima and current nodes.",
"source": "https://50ohm.de/NEA_strom_spannung_speisung_1.html",
"confidence": 8
},
"EG204": {
"revision": 1,
"explanation": "Current feeding means high current and low voltage at the feed point, a current maximum and voltage node, which gives low impedance.",
"source": "https://50ohm.de/NE_strom_spannung_speisung_1.html",
"confidence": 8
},
"EG205": {
"revision": 1,
"explanation": "Voltage feeding is the opposite case: high voltage and nearly zero current at the feed point, so the feed point is high impedance.",
"source": "https://50ohm.de/NE_strom_spannung_speisung_1.html",
"confidence": 8
},
"EG206": {
"revision": 1,
"explanation": "A half-wave dipole fed in the middle has its current maximum at the center, so it is current-fed on its fundamental frequency.",
"source": "https://50ohm.de/NE_strom_spannung_speisung_1.html",
"confidence": 8
},
"EG207": {
"revision": 1,
"explanation": "A center-fed half-wave dipole high above ground has a free-space feed impedance near 73 Ohm, so the rounded answer is 75 Ohm.",
"source": "https://50ohm.de/E_fusspunktimpedanz_1.html",
"confidence": 8
},
"EG208": {
"revision": 1,
"explanation": "Ground interaction changes a center-fed half-wave dipole impedance with height, typically over about 40 to 90 Ohm.",
"source": "https://50ohm.de/E_fusspunktimpedanz_1.html",
"confidence": 8
},
"EG209": {
"revision": 1,
"explanation": "A straight center-fed half-wave dipole is in the same practical impedance range as the height-dependent value, about 40 to 90 Ohm.",
"source": "https://50ohm.de/E_fusspunktimpedanz_1.html",
"confidence": 8
},
"EG210": {
"revision": 1,
"explanation": "A folded dipole approximately quadruples the feed impedance of a normal dipole, giving about 240 to 300 Ohm.",
"source": "https://50ohm.de/E_fusspunktimpedanz_1.html",
"confidence": 8
},
"EG211": {
"revision": 2,
"explanation": "A quarter-wave vertical against a counterpoise has a feed impedance near 35 Ohm with horizontal radials; sloping the radials downward raises it toward 50 Ohm, so the practical range is about 30 to 50 Ohm.",
"source": "https://50ohm.de/E_fusspunktimpedanz_1.html",
"confidence": 8
},
"EG212": {
"revision": 1,
"explanation": "In a Yagi-Uda antenna the feed is applied to the driven element, called the Strahler; reflector and directors are parasitic elements.",
"source": "https://50ohm.de/NE_yagi_uda_2.html",
"confidence": 8
},
"EG213": {
"revision": 1,
"explanation": "A ground-plane is unbalanced because the radial side is at earth or counterpoise potential; dipoles, folded dipoles, and Yagis are balanced antenna forms.",
"source": "https://50ohm.de/EA_antennenformen_2.html",
"confidence": 8
},
"EG214": {
"revision": 1,
"explanation": "A half-wave dipole pattern has two equal broad lobes perpendicular to the wire, matching the symmetric two-lobed diagram.",
"source": "https://50ohm.de/NE_antennenformen_2.html",
"confidence": 7
},
"EG215": {
"revision": 1,
"explanation": "The shown two-lobed pattern perpendicular to the wire is the typical radiation pattern of a half-wave dipole.",
"source": "https://50ohm.de/NE_antennenformen_2.html",
"confidence": 7
},
"EG216": {
"revision": 1,
"explanation": "The nearly circular horizontal pattern around the vertical radiator is typical of a ground-plane antenna viewed from above.",
"source": "https://50ohm.de/EA_antennenformen_2.html",
"confidence": 7
},
"EG217": {
"revision": 1,
"explanation": "A large forward lobe with a smaller rear lobe indicates directional gain, so the diagram is for a directional antenna.",
"source": "https://50ohm.de/EA_antennenformen_2.html",
"confidence": 7
},
"EG218": {
"revision": 1,
"explanation": "A Yagi-Uda radiation pattern has a strong main lobe toward the directors and smaller rear or side lobes, matching the shown diagram.",
"source": "https://50ohm.de/NE_yagi_uda_2.html",
"confidence": 7
},
"EG219": {
"revision": 1,
"explanation": "A vertical half-wave antenna radiates mainly perpendicular to the vertical element, giving a low elevation or flat radiation angle.",
"source": "https://50ohm.de/E_antennenformen_2.html",
"confidence": 8
},
"EG220": {
"revision": 1,
"explanation": "The suffix dBi means gain in dB relative to an isotropic radiator, the ideal antenna radiating equally in all directions.",
"source": "https://50ohm.de/NE_antennengewinn.html",
"confidence": 8
},
"EG221": {
"revision": 1,
"explanation": "dBd is referenced to a half-wave dipole, which is 2.15 dB above isotropic; 5 dBd + 2.15 dB = 7.15 dBi.",
"source": "https://50ohm.de/NE_antennengewinn.html",
"confidence": 8
},
"EG222": {
"revision": 1,
"explanation": "Antenna polarization is defined by the electric field orientation in the main radiation direction relative to the earth surface.",
"source": "https://50ohm.de/E_polarisation_2.html",
"confidence": 8
},
"EG223": {
"revision": 2,
"explanation": "Putting the transmitting antenna outdoors reduces coupling into house wiring and nearby electrical installations.",
"source": "https://50ohm.de/NE_slide_ne_antennen_uebertragungsleitungen.html",
"confidence": 8
},
"EG301": {
"revision": 1,
"explanation": "A line's characteristic impedance is set by its conductor geometry and dielectric; in the HF range it is roughly constant and does not depend on the load connected at the end.",
"source": "https://50ohm.de/E_uebertragungsleitungen_2.html",
"confidence": 8
},
"EG302": {
"revision": 1,
"explanation": "Good coaxial cable confines the RF field inside the shield in normal use, reducing unwanted radiation between station devices.",
"source": "https://50ohm.de/E_uebertragungsleitungen_2.html",
"confidence": 8
},
"EG303": {
"revision": 1,
"explanation": "N connectors are designed for 50 Ohm operation into the GHz range and are suitable for higher power and voltage than SMA or BNC in this comparison.",
"source": "https://50ohm.de/E_uebertragungsleitungen_2.html",
"confidence": 8
},
"EG304": {
"revision": 1,
"explanation": "A feed line is unbalanced when the two conductors are not equivalent, as in coax where the inner conductor and shield have different shapes and potentials.",
"source": "https://50ohm.de/E_uebertragungsleitungen_2.html",
"confidence": 8
},
"EG305": {
"revision": 1,
"explanation": "Open parallel-wire feed line avoids much dielectric loss and can withstand high voltages better than coaxial cable.",
"source": "https://50ohm.de/E_uebertragungsleitungen_2.html",
"confidence": 8
},
"EG306": {
"revision": 1,
"explanation": "Running RF feed lines directly beside mains leads can couple RF into the power wiring, so a shared cable duct can worsen interference risk.",
"source": "https://50ohm.de/E_uebertragungsleitungen_2.html",
"confidence": 8
},
"EG307": {
"revision": 1,
"explanation": "Cable losses in dB are added as positive attenuation values; the shown station layout sums to 5 dB of cable loss.",
"source": "https://50ohm.de/EA_kabeldaempfung_1.html",
"confidence": 7
},
"EG308": {
"revision": 1,
"explanation": "With SWR 1 there is no reflection; 100 W reduced to 50 W is a factor of 2 loss, which corresponds to 3 dB attenuation.",
"source": "https://50ohm.de/EA_kabeldaempfung_1.html",
"confidence": 8
},
"EG309": {
"revision": 1,
"explanation": "Only one quarter of the power remains, so the loss factor is 4; a power factor of 4 is about 6 dB.",
"source": "https://50ohm.de/EA_kabeldaempfung_1.html",
"confidence": 8
},
"EG310": {
"revision": 1,
"explanation": "Only one tenth of the power remains, so the loss factor is 10; a power factor of 10 is 10 dB.",
"source": "https://50ohm.de/EA_kabeldaempfung_1.html",
"confidence": 8
},
"EG311": {
"revision": 1,
"explanation": "Cable attenuation scales with length for the same cable and frequency: 20 dB per 100 m times 20/100 gives 4 dB.",
"source": "https://50ohm.de/E_kabeldaempfung_1.html",
"confidence": 8
},
"EG312": {
"revision": 1,
"explanation": "The cable-loss chart gives RG58 at 145 MHz as about 20 dB per 100 m, and the question length is exactly 100 m.",
"source": "https://50ohm.de/E_kabeldaempfung_1.html",
"confidence": 8
},
"EG313": {
"revision": 1,
"explanation": "RG58 is about 20 dB per 100 m at 145 MHz; for 15 m the attenuation is 20 x 15/100 = 3 dB.",
"source": "https://50ohm.de/E_kabeldaempfung_1.html",
"confidence": 8
},
"EG314": {
"revision": 1,
"explanation": "The chart value for RG174 at 145 MHz is about 40 dB per 100 m; for 50 m this is 40 x 50/100 = 20 dB.",
"source": "https://50ohm.de/E_kabeldaempfung_1.html",
"confidence": 8
},
"EG315": {
"revision": 1,
"explanation": "The chart gives about 7 dB per 100 m for the 12.7 mm PE-foam cable at 435 MHz; 40 m gives 7 x 40/100 = 2.8 dB.",
"source": "https://50ohm.de/E_kabeldaempfung_1.html",
"confidence": 8
},
"EG316": {
"revision": 1,
"explanation": "The chart gives about 20.5 dB per 100 m for the 10.3 mm PE-foam cable at 1296 MHz; 40 m gives about 8.2 dB.",
"source": "https://50ohm.de/E_kabeldaempfung_1.html",
"confidence": 8
},
"EG401": {
"revision": 2,
"explanation": "For SWR 3 the reflection coefficient is (3 - 1)/(3 + 1) = 0.5, so reflected power is 0.5 squared = 25 percent of 100 W, i.e. 25 W.",
"source": "https://50ohm.de/NEA_swr.html",
"confidence": 8
},
"EG402": {
"revision": 2,
"explanation": "SWR 3 gives voltage reflection coefficient 0.5; power reflection is 0.5 squared, so 25 percent of forward power is reflected.",
"source": "https://50ohm.de/NEA_swr.html",
"confidence": 8
},
"EG403": {
"revision": 2,
"explanation": "If SWR 3 reflects 25 percent of the forward power, the remaining 75 percent is delivered to the load.",
"source": "https://50ohm.de/NEA_swr.html",
"confidence": 8
},
"EG404": {
"revision": 1,
"explanation": "The current on the outside of the coax shield is the common-mode or mantle current, called Mantelstrom in the diagram.",
"source": "https://50ohm.de/NE_mantelwellen_1.html",
"confidence": 7
},
"EG405": {
"revision": 1,
"explanation": "Mantle waves make the coax shield radiate or receive as part of the antenna, which can disturb other devices and worsen the station's own reception.",
"source": "https://50ohm.de/NE_mantelwellen_1.html",
"confidence": 8
},
"EG406": {
"revision": 1,
"explanation": "A balanced dipole fed directly with unbalanced coax can drive common-mode current on the shield, distorting the radiation pattern and creating mantle waves.",
"source": "https://50ohm.de/NE_mantelwellen_1.html",
"confidence": 8
},
"EG407": {
"revision": 2,
"explanation": "A balun connects a balanced antenna such as a dipole to an unbalanced feed line such as coax while suppressing common-mode current.",
"source": "https://50ohm.de/NE_mantelwellen_1.html",
"confidence": 8
},
"EG408": {
"revision": 2,
"explanation": "Coax turns on a ferrite core form a common-mode choke, increasing impedance for mantle currents and therefore damping mantle waves.",
"source": "https://50ohm.de/NE_mantelwellen_1.html",
"confidence": 7
},
"EG501": {
"revision": 2,
"explanation": "EIRP is antenna input power multiplied by antenna gain in the chosen direction, with the gain referenced to an isotropic radiator.",
"source": "https://life.itu.int/radioclub/rr/art1.pdf",
"confidence": 9
},
"EG502": {
"revision": 2,
"explanation": "First subtract losses from transmitter power to get power at the antenna, then multiply by antenna gain referenced to an isotropic radiator.",
"source": "https://50ohm.de/NE_aequivalente_isotrope_strahlungsleistung_eirp_1.html",
"confidence": 8
},
"EG503": {
"revision": 2,
"explanation": "26 dBi is a gain factor of about 10^2.6 = 398; 0.25 W times 398 is about 100 W EIRP.",
"source": "https://50ohm.de/NE_aequivalente_isotrope_strahlungsleistung_eirp_1.html",
"confidence": 8
},
"EG504": {
"revision": 2,
"explanation": "36 dBi is a gain factor of about 10^3.6 = 3981; 5 W times 3981 is about 20000 W EIRP.",
"source": "https://50ohm.de/NE_aequivalente_isotrope_strahlungsleistung_eirp_1.html",
"confidence": 8
},
"EG505": {
"revision": 2,
"explanation": "The net isotropic gain is 11 dBi - 1 dB = 10 dB, a factor of 10, so 100 W becomes 1000 W EIRP.",
"source": "https://50ohm.de/NE_aequivalente_isotrope_strahlungsleistung_eirp_1.html",
"confidence": 8
},
"EG506": {
"revision": 2,
"explanation": "A dipole has 2.15 dBi gain, factor 1.64, and the cable loss is also factor 1.64; they cancel, leaving 75 W EIRP.",
"source": "https://50ohm.de/NE_aequivalente_isotrope_strahlungsleistung_eirp_1.html",
"confidence": 8
},
"EG507": {
"revision": 2,
"explanation": "10 dB cable loss reduces 100 W to 10 W at the dipole; dipole gain is factor 1.64 relative to isotropic, giving 16.4 W EIRP.",
"source": "https://50ohm.de/NE_aequivalente_isotrope_strahlungsleistung_eirp_1.html",
"confidence": 8
},
"EG508": {
"revision": 2,
"explanation": "5 dBd equals 7.15 dBi; after 2 dB cable loss the net gain is 5.15 dB, factor about 3.28, so 5 W becomes 16.4 W EIRP.",
"source": "https://50ohm.de/NE_aequivalente_isotrope_strahlungsleistung_eirp_1.html",
"confidence": 8
},
"EG509": {
"revision": 2,
"explanation": "11 dBd equals 13.15 dBi; minus 1 dB cable loss gives 12.15 dB, factor about 16.4, and 0.6 W times that is about 9.8 W.",
"source": "https://50ohm.de/NE_aequivalente_isotrope_strahlungsleistung_eirp_1.html",
"confidence": 8
},
"EG510": {
"revision": 2,
"explanation": "0 dBd equals 2.15 dBi; after 1.5 dB cable loss the net gain is 0.65 dB, factor about 1.17, so 8.5 W becomes about 9.9 W.",
"source": "https://50ohm.de/NE_aequivalente_isotrope_strahlungsleistung_eirp_1.html",
"confidence": 8
},
"EG511": {
"revision": 1,
"explanation": "BEMFV notification starts at 10 W EIRP. A 5.15 dBi antenna has factor about 3.28, so transmitter power must be at most about 10 / 3.28 = 3 W.",
"source": "https://www.gesetze-im-internet.de/bemfv/__9.html",
"confidence": 9
},
"EH101": {
"revision": 1,
"explanation": "HF long-distance propagation uses sky waves refracted by ionized, electrically charged regions of the ionosphere.",
"source": "https://50ohm.de/E_ionosphaere_2.html",
"confidence": 8
},
"EH102": {
"revision": 1,
"explanation": "The important HF DX regions are mainly the F regions, which lie roughly from 130 km up to about 450 km altitude.",
"source": "https://50ohm.de/E_ionosphaere_2.html",
"confidence": 8
},
"EH103": {
"revision": 1,
"explanation": "The F2 region persists high in the ionosphere and is the main refracting region for long-distance HF communication.",
"source": "https://50ohm.de/E_ionosphaere_2.html",
"confidence": 8
},
"EH104": {
"revision": 1,
"explanation": "At night the D region absorption largely disappears, and 80 m DX is then mainly enabled by F2-region refraction.",
"source": "https://50ohm.de/E_ionosphaere_2.html",
"confidence": 8
},
"EH105": {
"revision": 1,
"explanation": "The D region is strongly ionized by daylight and absorbs lower HF, especially 80 m and 160 m, causing strong daytime attenuation.",
"source": "https://50ohm.de/E_ionosphaere_2.html",
"confidence": 8
},
"EH106": {
"revision": 1,
"explanation": "Sporadic-E occurs as unusually ionized patches in the E region and can support upper-HF to VHF propagation in summer.",
"source": "https://50ohm.de/E_ionosphaere_2.html",
"confidence": 8
},
"EH107": {
"revision": 1,
"explanation": "Solar activity follows the sunspot cycle, whose average period is about 11 years.",
"source": "https://50ohm.de/E_ionosphaere_2.html",
"confidence": 8
},
"EH201": {
"revision": 1,
"explanation": "The dead zone is between the end of ground-wave coverage and the first point where the sky wave returns to earth.",
"source": "https://50ohm.de/E_tote_zone_1.html",
"confidence": 8
},
"EH202": {
"revision": 1,
"explanation": "Where ground wave and sky wave overlap, phase differences can make the received field strength vary, producing fading.",
"source": "https://50ohm.de/NE_fading.html",
"confidence": 8
},
"EH203": {
"revision": 1,
"explanation": "Signal weakening from overlap and interference of ground and sky waves is called fading.",
"source": "https://50ohm.de/NE_fading.html",
"confidence": 8
},
"EH204": {
"revision": 1,
"explanation": "MUF means Maximum Usable Frequency, the highest frequency still refracted back for the wanted path.",
"source": "https://50ohm.de/NE_muf_luf_1.html",
"confidence": 8
},
"EH205": {
"revision": 1,
"explanation": "At sunspot maximum solar UV and X-ray output are high, increasing ionization especially in the F region.",
"source": "https://50ohm.de/E_ionosphaere_2.html",
"confidence": 8
},
"EH206": {
"revision": 1,
"explanation": "More free electrons in the F2 region allow higher frequencies to be refracted back, so the MUF rises.",
"source": "https://50ohm.de/NE_muf_luf_1.html",
"confidence": 8
},
"EH207": {
"revision": 1,
"explanation": "To use frequencies above the current MUF, the refracting region needs stronger ionization so it can bend those higher frequencies back.",
"source": "https://50ohm.de/NE_muf_luf_1.html",
"confidence": 8
},
"EH208": {
"revision": 1,
"explanation": "Skip distance depends strongly on takeoff angle: a flatter radiation angle produces a longer hop, while a steeper angle returns sooner.",
"source": "https://50ohm.de/E_sprungdistanz_1.html",
"confidence": 8
},
"EH209": {
"revision": 1,
"explanation": "LUF is limited mainly by absorption, and lower HF absorption is controlled by the ionization level of the D region.",
"source": "https://50ohm.de/NE_muf_luf_1.html",
"confidence": 8
},
"EH210": {
"revision": 1,
"explanation": "During the day the D region absorbs low HF strongly, so 160 m and 80 m sky-wave signals are weak for worldwide communication.",
"source": "https://50ohm.de/E_ionosphaere_2.html",
"confidence": 8
},
"EH211": {
"revision": 1,
"explanation": "On 160 m in daytime, D-region absorption prevents useful sky-wave propagation, so propagation is mainly by ground wave.",
"source": "https://50ohm.de/E_bodenwelle.html",
"confidence": 8
},
"EH212": {
"revision": 1,
"explanation": "HF ground waves follow the earth beyond the optical horizon, but their attenuation increases at higher frequencies.",
"source": "https://50ohm.de/E_bodenwelle.html",
"confidence": 8
},
"EH213": {
"revision": 1,
"explanation": "The greyline is the twilight zone near sunrise and sunset where D-region absorption is reduced while higher-layer refraction can remain useful.",
"source": "https://50ohm.de/NE_greyline.html",
"confidence": 8
},
"EH214": {
"revision": 1,
"explanation": "A solar flare can abruptly increase D-region ionization and absorb HF sky waves; this shortwave fadeout is the Moegel-Dellinger effect.",
"source": "https://50ohm.de/E_moegel_dellinger_effekt.html",
"confidence": 8
},
"EH215": {
"revision": 1,
"explanation": "The Moegel-Dellinger effect causes a temporary loss or severe impairment of HF sky-wave propagation.",
"source": "https://50ohm.de/E_moegel_dellinger_effekt.html",
"confidence": 8
},
"EH216": {
"revision": 1,
"explanation": "Long path means the signal travels in the direction opposite the shortest bearing to the other station, around the longer side of the earth.",
"source": "https://50ohm.de/EA_langer_kurzer_weg_1.html",
"confidence": 8
},
"EH217": {
"revision": 1,
"explanation": "For Germany to VK, long path points away from the direct route and reaches Australia via the opposite direction, over South America.",
"source": "https://50ohm.de/EA_langer_kurzer_weg_1.html",
"confidence": 8
},
"EH218": {
"revision": 1,
"explanation": "Short-skip paths under 1000 km on 10 m are produced by refraction in localized sporadic-E ionization patches.",
"source": "https://50ohm.de/NE_sporadic_e_2.html",
"confidence": 8
},
"EH219": {
"revision": 1,
"explanation": "At sunspot maximum the F region is strongly ionized, so the 10 m band can support worldwide daytime contacts even with low power.",
"source": "https://50ohm.de/E_ionosphaere_2.html",
"confidence": 8
},
"EH301": {
"revision": 1,
"explanation": "The troposphere is the lower atmospheric layer where weather processes occur.",
"source": "https://50ohm.de/NE_troposphaere_2.html",
"confidence": 8
},
"EH302": {
"revision": 1,
"explanation": "VHF/UHF over-horizon propagation can occur when waves are bent, reflected, or scattered by tropospheric regions with different temperature and density.",
"source": "https://50ohm.de/NE_troposphaere_2.html",
"confidence": 8
},
"EH303": {
"revision": 1,
"explanation": "VHF long-distance contacts mainly use tropospheric propagation effects rather than HF-style ionospheric sky-wave propagation.",
"source": "https://50ohm.de/NE_troposphaere_2.html",
"confidence": 8
},
"EH304": {
"revision": 1,
"explanation": "Sporadic-E is refraction by locally limited, unusually highly ionized regions inside the E layer.",
"source": "https://50ohm.de/NE_sporadic_e_2.html",
"confidence": 8
},
"EH305": {
"revision": 2,
"explanation": "Aurora makes CW tone quality rough and unstable, so the report uses R and S plus A for Aurora instead of a normal tone rating.",
"source": "https://50ohm.de/E_slide_e_wellenausbreitung.html",
"confidence": 8
},
"EI101": {
"revision": 1,
"explanation": "Voltage is measured across a component, so the meter is connected in parallel; high input resistance prevents the meter from loading the circuit.",
"source": "https://50ohm.de/E_strom_spannung_messung_2.html",
"confidence": 8
},
"EI102": {
"revision": 1,
"explanation": "To use Ohm's law for a resistor, current must be measured in series through it and voltage in parallel across it.",
"source": "https://50ohm.de/E_strom_spannung_messung_2.html",
"confidence": 7
},
"EI103": {
"revision": 1,
"explanation": "The pointer is at 29 percent of full scale; on the 10 V range that is 0.29 x 10 V = 2.9 V.",
"source": "https://50ohm.de/NEA_zeigerinstrumente_ablesen.html",
"confidence": 7
},
"EI104": {
"revision": 1,
"explanation": "On the 300 V range the same pointer position corresponds to about 29 percent of full scale, so 0.29 x 300 V is about 88 V.",
"source": "https://50ohm.de/NEA_zeigerinstrumente_ablesen.html",
"confidence": 7
},
"EI201": {
"revision": 1,
"explanation": "A VNA measures frequency-dependent impedance and reflection behavior, so it is suited to finding resonances and impedances of tuned circuits and antennas.",
"source": "https://50ohm.de/NEA_vna_1.html",
"confidence": 8
},
"EI202": {
"revision": 1,
"explanation": "Resonance can be calculated from measured L and C or found directly by sweeping the circuit with a VNA.",
"source": "https://50ohm.de/NEA_vna_1.html",
"confidence": 8
},
"EI203": {
"revision": 1,
"explanation": "A vector network analyzer directly measures complex impedance, including resistance, reactance, and reflection/SWR quantities.",
"source": "https://50ohm.de/NEA_vna_1.html",
"confidence": 8
},
"EI204": {
"revision": 1,
"explanation": "Impedance measurement is a core VNA use because it compares voltage/current or incident/reflected waves over frequency.",
"source": "https://50ohm.de/NEA_vna_1.html",
"confidence": 8
},
"EI205": {
"revision": 1,
"explanation": "A VNA must be calibrated with the measurement setup so its reference plane and systematic errors are corrected before use.",
"source": "https://50ohm.de/NEA_vna_1.html",
"confidence": 8
},
"EI206": {
"revision": 1,
"explanation": "Open and short should reflect almost all power, giving very high SWR, while a matched load should show SWR near 1.",
"source": "https://50ohm.de/NEA_vna_1.html",
"confidence": 8
},
"EI301": {
"revision": 2,
"explanation": "The displayed sine period spans 8 divisions; at 0.5 ms per division the period is 8 x 0.5 ms = 4 ms.",
"source": "https://50ohm.de/NE_oszilloskop_1.html",
"confidence": 7
},
"EI302": {
"revision": 2,
"explanation": "The period is 4 ms, so frequency is 1 / 0.004 s = 250 Hz.",
"source": "https://50ohm.de/NE_oszilloskop_1.html",
"confidence": 8
},
"EI303": {
"revision": 2,
"explanation": "Pulse duration is read from the middle of the rising edge to the middle of the falling edge; the shown interval is 200 microseconds.",
"source": "https://50ohm.de/E_slide_e_strom_spannung_widerstand_leistung_energie.html",
"confidence": 7
},
"EI304": {
"revision": 2,
"explanation": "Audio distortion changes the waveform shape, and an oscilloscope displays waveform shape directly.",
"source": "https://50ohm.de/E_slide_e_strom_spannung_widerstand_leistung_energie.html",
"confidence": 8
},
"EI401": {
"revision": 2,
"explanation": "An SWR meter measures the match between feed line and load, so in transmitter use it indicates antenna-system matching.",
"source": "https://50ohm.de/NE_slide_ne_antennen_uebertragungsleitungen.html",
"confidence": 8
},
"EI402": {
"revision": 2,
"explanation": "The instrument for showing the match between a UHF transmitter and its feed line is an SWR meter.",
"source": "https://50ohm.de/NE_slide_ne_antennen_uebertragungsleitungen.html",
"confidence": 8
},
"EI403": {
"revision": 2,
"explanation": "In transmit operation SWR is measured with an SWR bridge that compares forward and reflected power on the line.",
"source": "https://50ohm.de/NE_slide_ne_antennen_uebertragungsleitungen.html",
"confidence": 8
},
"EI404": {
"revision": 2,
"explanation": "To judge the antenna itself, the SWR meter should be as close to the antenna as possible, between antenna cable and antenna.",
"source": "https://50ohm.de/NE_slide_ne_antennen_uebertragungsleitungen.html",
"confidence": 8
},
"EI405": {
"revision": 2,
"explanation": "To check whether the whole antenna system is well matched to the transmitter, the SWR meter belongs at the transmitter output, point 1.",
"source": "https://50ohm.de/NE_slide_ne_antennen_uebertragungsleitungen.html",
"confidence": 7
},
"EI501": {
"revision": 1,
"explanation": "An unmodulated RF signal has a single stable frequency, which a frequency counter can count directly.",
"source": "https://50ohm.de/NE_frequenzmessung_1.html",
"confidence": 8
},
"EI502": {
"revision": 1,
"explanation": "The marked digit is in the 10^3 Hz position of the counter display, so its place value is one kilohertz.",
"source": "https://50ohm.de/NE_frequenzmessung_1.html",
"confidence": 7
},
"EI503": {
"revision": 1,
"explanation": "In this display the marked digit is in the 10 Hz position, so its place value is ten hertz.",
"source": "https://50ohm.de/NE_frequenzmessung_1.html",
"confidence": 7
},
"EI504": {
"revision": 1,
"explanation": "A 10:1 prescaler divides the input by 10 before counting, so the real frequency is 10 x 14.5625 MHz = 145.625 MHz.",
"source": "https://50ohm.de/NE_frequenzmessung_1.html",
"confidence": 8
},
"EJ101": {
"revision": 1,
"explanation": "Conducted RF interference enters equipment through attached leads such as mains, antenna, or speaker cables; that is Einströmung.",
"source": "https://50ohm.de/E_stoerungen_elektronischer_geraete_1.html",
"confidence": 8
},
"EJ102": {
"revision": 1,
"explanation": "Radiated RF entering through poor enclosure shielding is Einstrahlung, distinct from conducted entry via cables.",
"source": "https://50ohm.de/E_stoerungen_elektronischer_geraete_1.html",
"confidence": 8
},
"EJ103": {
"revision": 1,
"explanation": "Even a clean wanted signal can overload nearby receiver stages or otherwise influence them, so the issue is overload or disturbing influence, not spurious emission.",
"source": "https://50ohm.de/E_stoerungen_elektronischer_geraete_1.html",
"confidence": 8
},
"EJ104": {
"revision": 1,
"explanation": "Lower transmitter power lowers field strength and coupling risk, so use only the minimum needed for satisfactory communication.",
"source": "https://50ohm.de/E_stoerungen_elektronischer_geraete_1.html",
"confidence": 8
},
"EJ105": {
"revision": 1,
"explanation": "In dense residential areas during TV viewing hours, the practical interference-reduction step is to transmit with no more power than needed for reliable communication.",
"source": "https://50ohm.de/NE_stoerungen_elektronischer_geraete_1.html",
"confidence": 8
},
"EJ106": {
"revision": 1,
"explanation": "A high-gain 432 MHz antenna pointed at a TV receive antenna can create a very strong local signal and overload the TV receiver input.",
"source": "https://50ohm.de/E_stoerungen_elektronischer_geraete_1.html",
"confidence": 8
},
"EJ107": {
"revision": 1,
"explanation": "Receiver overload drives input stages out of their normal range, reducing effective sensitivity or even blocking reception.",
"source": "https://50ohm.de/E_stoerungen_elektronischer_geraete_1.html",
"confidence": 8
},
"EJ108": {
"revision": 1,
"explanation": "A nearly closed metal enclosure provides RF shielding by enclosing the circuitry in a conductive shell.",
"source": "https://50ohm.de/E_stoerungen_elektronischer_geraete_1.html",
"confidence": 8
},
"EJ109": {
"revision": 1,
"explanation": "A parallel nearby HF antenna can inductively or capacitively couple RF current into the 230 V mains wiring.",
"source": "https://50ohm.de/E_stoerungen_elektronischer_geraete_1.html",
"confidence": 8
},
"EJ110": {
"revision": 1,
"explanation": "Running the 80 m wire at right angles to the row of houses avoids long parallel coupling to building wiring and neighboring installations.",
"source": "https://50ohm.de/E_standortwahl.html",
"confidence": 8
},
"EJ111": {
"revision": 1,
"explanation": "A separate RF earth for transmitting antennas helps keep RF currents out of house wiring and therefore lowers in-house interference risk.",
"source": "https://50ohm.de/E_stoerungen_elektronischer_geraete_1.html",
"confidence": 8
},
"EJ112": {
"revision": 1,
"explanation": "LED lamps with mains-connected electronics can be susceptible to RF influence, unlike simple thermal or motor loads in the alternatives.",
"source": "https://50ohm.de/E_stoerungen_elektronischer_geraete_1.html",
"confidence": 8
},
"EJ113": {
"revision": 1,
"explanation": "Strong RF can be rectified by nonlinear semiconductor junctions in an audio power stage, producing audible noise even when the stereo is nominally off.",
"source": "https://50ohm.de/E_stoerungen_elektronischer_geraete_1.html",
"confidence": 8
},
"EJ114": {
"revision": 1,
"explanation": "If RF is entering the audio power stage through speaker leads, shielding those leads reduces the conducted RF path.",
"source": "https://50ohm.de/E_slide_e_sender.html?print-pdf=&showNotes=true",
"confidence": 8
},
"EJ115": {
"revision": 1,
"explanation": "A shielded intercom cable reduces RF pickup on the wiring that otherwise conducts the interfering signal into the door-phone electronics.",
"source": "https://50ohm.de/E_slide_e_sender.html?print-pdf=&showNotes=true",
"confidence": 8
},
"EJ116": {
"revision": 1,
"explanation": "A DVB-T2 input should pass UHF TV frequencies while rejecting the much lower 28 MHz amateur signal, so a high-pass filter is appropriate.",
"source": "https://50ohm.de/E_stoerungen_elektronischer_geraete_1.html",
"confidence": 8
},
"EJ117": {
"revision": 1,
"explanation": "For HF interference in a TV antenna lead, use the high-pass filter: it rejects low HF while passing the higher TV bands.",
"source": "https://50ohm.de/E_stoerungen_elektronischer_geraete_1.html",
"confidence": 7
},
"EJ118": {
"revision": 1,
"explanation": "A mantle-wave choke raises impedance for common-mode RF on the outside of the coax shield, suppressing those RF interference currents.",
"source": "https://50ohm.de/E_slide_e_sender.html?print-pdf=&showNotes=true",
"confidence": 8
},
"EJ119": {
"revision": 1,
"explanation": "If 144 MHz RF is induced as common-mode current on the broadcast receiver coax, a mantle-wave choke before the receiver reduces that current.",
"source": "https://50ohm.de/E_slide_e_sender.html?print-pdf=&showNotes=true",
"confidence": 8
},
"EJ120": {
"revision": 1,
"explanation": "Intermodulation creates phantom signals from two or more strong signals; removing one participating signal removes the product.",
"source": "https://50ohm.de/E_slide_e_sender.html?print-pdf=&showNotes=true",
"confidence": 8
},
"EJ121": {
"revision": 1,
"explanation": "Corroded metal contacts are nonlinear and can rectify or mix nearby transmitter signals, creating unwanted products that disturb TV reception.",
"source": "https://50ohm.de/E_stoerungen_elektronischer_geraete_1.html",
"confidence": 8
},
"EJ122": {
"revision": 1,
"explanation": "The first useful step is to check whether the disturbance actually coincides in time with your transmissions.",
"source": "https://50ohm.de/E_stoerungen_elektronischer_geraete_1.html",
"confidence": 8
},
"EJ123": {
"revision": 2,
"explanation": "An indoor antenna sits inside the noisy local RF environment and gets little wanted signal; an outdoor antenna can be placed away from the interferer and offers more gain and directivity, improving the wanted-to-interferer ratio.",
"source": "https://50ohm.de/E_slide_e_sender.html?print-pdf=&showNotes=true",
"confidence": 8
},
"EJ124": {
"revision": 1,
"explanation": "After cooperative mitigation attempts fail, the proper next step is to ask the responsible Bundesnetzagentur field office to examine the situation.",
"source": "https://50ohm.de/E_stoerungen_elektronischer_geraete_1.html",
"confidence": 8
},
"EJ201": {
"revision": 1,
"explanation": "A pure sine wave contains only one frequency component; non-sinusoidal carriers contain harmonics that can cause interference.",
"source": "https://50ohm.de/NE_unerwuenschte_aussendungen_2.html",
"confidence": 8
},
"EJ202": {
"revision": 1,
"explanation": "Harmonics are unwanted multiples of the wanted RF frequency, so an harmonic filter is used to reduce them.",
"source": "https://50ohm.de/NE_unerwuenschte_aussendungen_2.html",
"confidence": 8
},
"EJ203": {
"revision": 1,
"explanation": "A low-pass filter passes the wanted fundamental output while attenuating higher-frequency harmonics.",
"source": "https://50ohm.de/NE_unerwuenschte_aussendungen_2.html",
"confidence": 8
},
"EJ204": {
"revision": 1,
"explanation": "Between transmitter and antenna, a low-pass filter is best for reducing harmonic radiation above the operating frequency.",
"source": "https://50ohm.de/NE_unerwuenschte_aussendungen_2.html",
"confidence": 8
},
"EJ205": {
"revision": 1,
"explanation": "A UHF transmitter's harmonics are at still higher frequencies, so a following low-pass filter attenuates them while passing the wanted UHF signal.",
"source": "https://50ohm.de/NE_unerwuenschte_aussendungen_2.html",
"confidence": 8
},
"EJ206": {
"revision": 1,
"explanation": "The correct circuit is the low-pass output filter, with series inductors and shunt capacitors arranged to pass the fundamental and shunt harmonics.",
"source": "https://50ohm.de/NE_unerwuenschte_aussendungen_2.html",
"confidence": 7
},
"EJ207": {
"revision": 1,
"explanation": "A harmonic-reduction filter should pass the HF operating range and roll off higher frequencies, i.e. a low-pass characteristic.",
"source": "https://50ohm.de/NE_unerwuenschte_aussendungen_2.html",
"confidence": 7
},
"EJ208": {
"revision": 1,
"explanation": "For an HF multiband transmitter, the output filter should pass all HF bands while attenuating frequencies above them, so the wide low-pass curve is best.",
"source": "https://50ohm.de/NE_unerwuenschte_aussendungen_2.html",
"confidence": 7
},
"EJ209": {
"revision": 1,
"explanation": "Unwanted-emission power is assessed at the transmitter output including normally used inline devices such as the SWR meter and any low-pass filter.",
"source": "https://50ohm.de/NE_unerwuenschte_aussendungen_2.html",
"confidence": 8
},
"EJ210": {
"revision": 1,
"explanation": "Keeping SSB occupied bandwidth to at most about 2.7 kHz limits spillover onto adjacent frequencies.",
"source": "https://50ohm.de/E_ssb_2.html",
"confidence": 8
},
"EJ211": {
"revision": 1,
"explanation": "SSB speech audio above about 3 kHz would widen the RF sideband unnecessarily, increasing adjacent-channel interference risk.",
"source": "https://50ohm.de/E_ssb_2.html",
"confidence": 8
},
"EJ212": {
"revision": 1,
"explanation": "For FM AFSK, occupied bandwidth rises with frequency deviation, so lowering audio drive or deviation reduces the transmitted bandwidth.",
"source": "https://50ohm.de/EA_fm_2.html",
"confidence": 8
},
"EJ213": {
"revision": 1,
"explanation": "Overdriving a power amplifier makes it nonlinear, creating distortion products and a high level of unwanted emissions.",
"source": "https://50ohm.de/NE_unerwuenschte_aussendungen_2.html",
"confidence": 8
},
"EJ214": {
"revision": 1,
"explanation": "An overdriven SSB linear amplifier produces intermodulation products that spread into neighboring frequencies.",
"source": "https://50ohm.de/NE_unerwuenschte_aussendungen_2.html",
"confidence": 8
},
"EJ215": {
"revision": 1,
"explanation": "Too much microphone gain overdrives the SSB transmit chain and creates splatter affecting nearby stations.",
"source": "https://50ohm.de/NE_unerwuenschte_aussendungen_2.html",
"confidence": 8
},
"EJ216": {
"revision": 1,
"explanation": "Poor frequency stability can make the transmitter drift, potentially moving the emission outside authorized band limits.",
"source": "https://50ohm.de/NE_unerwuenschte_aussendungen_2.html",
"confidence": 8
},
"EJ217": {
"revision": 1,
"explanation": "If ALC acts during SSB digital modes, it can distort the audio/RF envelope and create unwanted products on neighboring frequencies.",
"source": "https://50ohm.de/NEA_digimode_ssb.html",
"confidence": 8
},
"EJ218": {
"revision": 1,
"explanation": "The audio drive for FT8, JS8, PSK31, and similar modes should be low enough that ALC does not engage, avoiding distortion and splatter.",
"source": "https://50ohm.de/NEA_digimode_ssb.html",
"confidence": 8
},
"EJ219": {
"revision": 1,
"explanation": "If ALC is causing interference in SSB digital operation, reduce the audio input level so the transmitter is no longer driven into ALC action.",
"source": "https://50ohm.de/NEA_digimode_ssb.html",
"confidence": 8
},
"EK101": {
"revision": 1,
"explanation": "RF energy absorption in the human body depends on frequency, including penetration depth and resonance effects, so exposure limits are frequency-dependent.",
"source": "https://50ohm.de/E_personenschutzabstand_grenzwerte.html",
"confidence": 8
},
"EK102": {
"revision": 1,
"explanation": "The 26th BImSchV uses different time references: Annex 1b values are RMS-averaged over 6 minutes, Annex 1a values are short-term RMS values, and Annex 3 uses instantaneous peak limits for pulsed fields.",
"source": "https://www.gesetze-im-internet.de/bimschv_26/BJNR196600996.html",
"confidence": 9
},
"EK103": {
"revision": 1,
"explanation": "For active body aids, the relevant protection criterion is the maximum instantaneous field value, not a 3- or 6-minute average.",
"source": "https://50ohm.de/E_personenschutzabstand_grenzwerte.html",
"confidence": 8
},
"EK104": {
"revision": 1,
"explanation": "13 dBd is 15.15 dBi, a factor about 32.7; 6 W therefore gives about 196 W EIRP, well above the 10 W EIRP amateur-station threshold requiring proof/notification duties.",
"source": "https://www.gesetze-im-internet.de/bemfv/__8.html",
"confidence": 9
},
"EK105": {
"revision": 1,
"explanation": "At 80 m the 3.65 m result lies in the reactive near field, where the far-field approximation is invalid, so measurement, simulation, or near-field calculation is needed.",
"source": "https://50ohm.de/E_naeherungsformel_1.html",
"confidence": 8
},
"EK106": {
"revision": 1,
"explanation": "The far-field approximation is invalid below roughly lambda/(2*pi); for 160 m this is about 25.5 m and for 80 m about 12.7 m.",
"source": "https://50ohm.de/E_naeherungsformel_1.html",
"confidence": 8
},
"EK107": {
"revision": 2,
"explanation": "When the safety distance is calculated from the antenna field, the distance must be maintained from every radiating point of the antenna, not only the feed point.",
"source": "https://50ohm.de/NEA_slide_nea_personenschutzabstand.html",
"confidence": 8
},
"EK108": {
"revision": 1,
"explanation": "Convert 7.5 dBd to 9.65 dBi, subtract 1.5 dB cable loss for 8.15 dB net gain, then use d = sqrt(30 x EIRP) / 28 V/m; the result is about 5.0 m.",
"source": "https://50ohm.de/E_naeherungsformel_1.html",
"confidence": 8
},
"EK201": {
"revision": 1,
"explanation": "Microwave antennas can concentrate high fields in a narrow beam, so people should not stay in the direct beam path of transmitting antennas.",
"source": "https://50ohm.de/NE_strahlengang_aufenthalt.html",
"confidence": 8
},
"EK202": {
"revision": 1,
"explanation": "Transmitting antennas can have high RF voltages on their conductors; touching them can cause burns and other RF voltage injuries.",
"source": "https://50ohm.de/E_slide_e_sicherheit.html?print-pdf=&showNotes=true",
"confidence": 8
},
"EK203": {
"revision": 1,
"explanation": "Power-supply capacitors can remain charged after the mains plug is removed, so opening disconnected equipment can still expose you to electric shock.",
"source": "https://50ohm.de/NEA_slide_nea_sicherheit.html?print-pdf=&showNotes=true",
"confidence": 8
},
"EK204": {
"revision": 1,
"explanation": "A fuse is a safety component matched to current and trip speed; after repair it must be replaced with the same current rating and same fast characteristic.",
"source": "https://50ohm.de/E_sicherungen.html",
"confidence": 8
},
"EK205": {
"revision": 1,
"explanation": "For a 3-core mains cable the standard colors are PE green-yellow, live conductor brown, and neutral blue.",
"source": "https://50ohm.de/E_spannungsquelle.html",
"confidence": 8
},
"EK206": {
"revision": 1,
"explanation": "Ungrounded wire antennas can accumulate static charge from weather such as rain or hail, creating a safety hazard.",
"source": "https://50ohm.de/E_slide_e_sicherheit.html?print-pdf=&showNotes=true",
"confidence": 8
},
"EK207": {
"revision": 1,
"explanation": "High-value bleed resistors drain static charge to the station earth while their high resistance avoids significantly affecting RF operation.",
"source": "https://50ohm.de/NE_slide_ne_sicherheit.html?print-pdf=&showNotes=true",
"confidence": 8
},
"EK208": {
"revision": 1,
"explanation": "Bonding all antenna coax shields together and to the main earthing bar prevents dangerous potential differences between coax systems.",
"source": "https://50ohm.de/NE_slide_ne_sicherheit.html",
"confidence": 8
},
"EK209": {
"revision": 2,
"explanation": "An existing building earthing system per VDE 0855-300 may be used for antenna earthing; no separate electrode or special approval is required.",
"source": "https://50ohm.de/NE_blitzerdung.html",
"confidence": 8
},
"EK210": {
"revision": 1,
"explanation": "VDE 0855-300 requires a solid earthing conductor, with example minimum cross sections of 16 mm2 copper, 25 mm2 aluminium, or 50 mm2 steel.",
"source": "https://50ohm.de/NE_blitzerdung.html",
"confidence": 8
},
"EK211": {
"revision": 1,
"explanation": "Connecting an antenna mast to an existing lightning protection system changes that system and must be included in the lightning protection concept by a qualified specialist.",
"source": "https://50ohm.de/NE_blitzerdung.html",
"confidence": 8
},
"NA101": {
"revision": 2,
"explanation": "Cutting at $2/3$ of 20 m gives a $13.33$ m piece; the remaining $1/3$ is $6.67$ m.",
"source": "https://www.bipm.org/en/publications/si-brochure",
"confidence": 8
},
"NA102": {
"revision": 1,
"explanation": "The maximum count is the whole-number quotient: $250/18.5 = 13.5$, so only 13 complete antennas fit before the remaining wire is too short.",
"source": "https://www.bipm.org/en/publications/si-brochure",
"confidence": 8
},
"NA103": {
"revision": 1,
"explanation": "Mass scales linearly with length for the same wire: $55/210$ of 100 m is about 26.2 m.",
"source": "https://www.bipm.org/en/publications/si-brochure",
"confidence": 8
},
"NA201": {
"revision": 1,
"explanation": "Electric potential difference is measured in volts; amperes measure current, ohms resistance, and ampere-hours charge capacity.",
"source": "https://www.bipm.org/en/publications/si-brochure",
"confidence": 8
},
"NA202": {
"revision": 1,
"explanation": "Electric current is the rate of flow of charge, and the SI unit for current is the ampere.",
"source": "https://www.bipm.org/en/publications/si-brochure",
"confidence": 8
},
"NA203": {
"revision": 1,
"explanation": "Electrical resistance is measured in ohms, the unit that relates voltage and current through Ohm's law.",
"source": "https://www.bipm.org/en/publications/si-brochure",
"confidence": 8
},
"NA204": {
"revision": 1,
"explanation": "Electrical power is measured in watts; joule is energy, kilowatt-hour is energy, and ampere-hour is charge capacity.",
"source": "https://www.bipm.org/en/publications/si-brochure",
"confidence": 8
},
"NA205": {
"revision": 1,
"explanation": "Wavelength is a length, so it is normally expressed in metres rather than hertz or seconds.",
"source": "https://www.bipm.org/en/publications/si-brochure",
"confidence": 8
},
"NA206": {
"revision": 1,
"explanation": "Frequency is cycles per second, and the named SI unit for that is hertz.",
"source": "https://www.bipm.org/en/publications/si-brochure",
"confidence": 8
},
"NA207": {
"revision": 1,
"explanation": "One hertz means one cycle per second, so dimensionally $Hz = 1/s$.",
"source": "https://www.bipm.org/en/publications/si-brochure",
"confidence": 8
},
"NA208": {
"revision": 1,
"explanation": "Milli means $10^{-3}$, so one volt is 1000 millivolts and 4.2 V is 4200 mV.",
"source": "https://www.bipm.org/en/publications/si-brochure",
"confidence": 8
},
"NA209": {
"revision": 1,
"explanation": "Milli means $10^{-3}$; therefore 42 mA is $42/1000$ A, or 0.042 A.",
"source": "https://www.bipm.org/en/publications/si-brochure",
"confidence": 8
},
"NA210": {
"revision": 1,
"explanation": "Milli means one thousandth, so one watt contains 1000 milliwatts.",
"source": "https://www.bipm.org/en/publications/si-brochure",
"confidence": 8
},
"NA211": {
"revision": 2,
"explanation": "$0.010\\,\\mathrm{W} \\cdot 1000\\,\\mathrm{mW/W} = 10\\,\\mathrm{mW}$.",
"source": "https://www.bipm.org/en/publications/si-brochure",
"confidence": 8
},
"NA212": {
"revision": 1,
"explanation": "Mega means $10^6$; $144000000$ Hz divided by $10^6$ is 144 MHz.",
"source": "https://www.bipm.org/en/publications/si-brochure",
"confidence": 8
},
"NA213": {
"revision": 1,
"explanation": "145000000 periods per second is 145000000 Hz, which is 145 MHz after dividing by $10^6$.",
"source": "https://www.bipm.org/en/publications/si-brochure",
"confidence": 8
},
"NB101": {
"revision": 2,
"explanation": "Among the listed metals, copper has the lowest resistivity at room temperature, so it has the highest conductivity in that group.",
"source": "https://50ohm.de/N_leiter_nichtleiter.html",
"confidence": 7
},
"NB102": {
"revision": 2,
"explanation": "Silver has even lower resistivity than copper, gold or tin at room temperature, so it is the best conductor in this list.",
"source": "https://50ohm.de/N_leiter_nichtleiter.html",
"confidence": 7
},
"NB103": {
"revision": 2,
"explanation": "Tin has higher resistivity than copper, gold and aluminium, so it is the poorest conductor among the listed metals.",
"source": "https://50ohm.de/N_leiter_nichtleiter.html",
"confidence": 7
},
"NB104": {
"revision": 2,
"explanation": "Porcelain and the plastics PE and PS are insulating materials; the other options include metals such as tungsten, brass or bronze.",
"source": "https://50ohm.de/N_leiter_nichtleiter.html",
"confidence": 7
},
"NB201": {
"revision": 1,
"explanation": "The alternating long and short parallel plates are the conventional schematic symbol for a battery or cell stack.",
"source": "IEC 60617 graphical symbols for diagrams",
"confidence": 7
},
"NB202": {
"revision": 1,
"explanation": "The shown reference symbol marks circuit ground or chassis reference, not an active source or switch.",
"source": "IEC 60617 graphical symbols for diagrams",
"confidence": 7
},
"NB203": {
"revision": 1,
"explanation": "In a battery symbol the longer plate denotes the positive terminal and the shorter plate denotes the negative terminal.",
"source": "IEC 60617 graphical symbols for diagrams",
"confidence": 7
},
"NB204": {
"revision": 2,
"explanation": "Series-connected cells add their voltages; six 1.5 V cells give $6 \\cdot 1.5 V = 9 V$.",
"source": "https://50ohm.de/N_batterien_und_akkus.html",
"confidence": 8
},
"NB205": {
"revision": 2,
"explanation": "The voltmeter is connected across two 1.5 V cells in series, so it reads their sum: 3 V.",
"source": "https://50ohm.de/N_spannungsmessung.html",
"confidence": 7
},
"NB206": {
"revision": 2,
"explanation": "Both meter leads are on points with the same potential in the shown circuit, so the potential difference is 0 V.",
"source": "https://50ohm.de/N_spannungsmessung.html",
"confidence": 7
},
"NB207": {
"revision": 2,
"explanation": "Current needs a complete closed loop through a source and load; the shown connection alone does not close a usable circuit.",
"source": "https://50ohm.de/N_slide_n_bauteile_und_schaltkreise.html",
"confidence": 7
},
"NB301": {
"revision": 1,
"explanation": "Electromagnetic waves in free space travel at the speed of light, about $3 \\cdot 10^8$ m/s or 300000 km/s.",
"source": "https://www.bipm.org/en/publications/si-brochure",
"confidence": 8
},
"NB302": {
"revision": 2,
"explanation": "Use $f = c/\\lambda$: $300000000 / 2.08$ is about 144 MHz.",
"source": "https://50ohm.de/N_wellenlaenge.html",
"confidence": 8
},
"NB303": {
"revision": 2,
"explanation": "Use $\\lambda = c/f$: $300000000 / 433500000$ is about 0.69 m.",
"source": "https://50ohm.de/N_wellenlaenge.html",
"confidence": 8
},
"NB304": {
"revision": 2,
"explanation": "Radio waves are transverse, so the receiving antenna should match the electric-field orientation; mismatched polarisation causes avoidable loss.",
"source": "https://50ohm.de/NEA_polarisation.html",
"confidence": 7
},
"NB401": {
"revision": 2,
"explanation": "A sinusoidal AC waveform is the smooth periodic curve with equal positive and negative half cycles shown in the correct figure.",
"source": "https://50ohm.de/N_sinusschwingung.html",
"confidence": 7
},
"NB402": {
"revision": 2,
"explanation": "Amplitude is the maximum displacement from the centre line; marker 1 points to that vertical height.",
"source": "https://50ohm.de/N_wellenlaenge.html",
"confidence": 7
},
"NB403": {
"revision": 2,
"explanation": "Wavelength is the spatial distance for one complete cycle, which is what marker 2 spans in the wave snapshot.",
"source": "https://50ohm.de/N_wellenlaenge.html",
"confidence": 7
},
"NB404": {
"revision": 2,
"explanation": "On an oscilloscope trace, amplitude is the vertical distance from the reference level to a peak; marker 1 indicates that height.",
"source": "https://50ohm.de/N_sinusschwingung.html",
"confidence": 7
},
"NB405": {
"revision": 2,
"explanation": "Period is the time for one complete cycle, so the horizontal interval marked 2 is one period.",
"source": "https://50ohm.de/N_sinusschwingung.html",
"confidence": 7
},
"NB501": {
"revision": 1,
"explanation": "Ohm's law relates voltage, current and resistance as $U = R \\cdot I$.",
"source": "IEC 60050 International Electrotechnical Vocabulary",
"confidence": 8
},
"NB502": {
"revision": 1,
"explanation": "Rearranging Ohm's law gives current as voltage divided by resistance: $I = U/R$.",
"source": "IEC 60050 International Electrotechnical Vocabulary",
"confidence": 8
},
"NB503": {
"revision": 1,
"explanation": "Rearranging $U = R \\cdot I$ for resistance gives $R = U/I$.",
"source": "IEC 60050 International Electrotechnical Vocabulary",
"confidence": 8
},
"NB504": {
"revision": 1,
"explanation": "Using Ohm's law with the shown resistance, $U = R \\cdot I$ gives 9.000 V for 90 mA.",
"source": "IEC 60050 International Electrotechnical Vocabulary",
"confidence": 8
},
"NB505": {
"revision": 1,
"explanation": "Resistance is found from $R = U/I$; applying the voltage and current shown in the figure gives 40 ohm.",
"source": "IEC 60050 International Electrotechnical Vocabulary",
"confidence": 7
},
"NB601": {
"revision": 1,
"explanation": "DC input power is $P = U \\cdot I$, so $13.8 V \\cdot 1.5 A = 20.7 W$.",
"source": "IEC 60050 International Electrotechnical Vocabulary",
"confidence": 8
},
"NB602": {
"revision": 1,
"explanation": "Power converted to heat is $P = U \\cdot I$; 50 V times 0.050 A gives 2.5 W.",
"source": "IEC 60050 International Electrotechnical Vocabulary",
"confidence": 8
},
"NB603": {
"revision": 1,
"explanation": "20 mA is 0.020 A, and $3.2 V \\cdot 0.020 A = 0.064 W = 64.0 mW$.",
"source": "IEC 60050 International Electrotechnical Vocabulary",
"confidence": 8
},
"NB604": {
"revision": 1,
"explanation": "From $P = U \\cdot I$, current is $I = P/U = 100 W / 12 V = 8.33 A$.",
"source": "IEC 60050 International Electrotechnical Vocabulary",
"confidence": 8
},
"NB605": {
"revision": 1,
"explanation": "A 3 W load at 12 V draws $I = P/U = 3/12 = 0.25 A$, which is 250 mA.",
"source": "IEC 60050 International Electrotechnical Vocabulary",
"confidence": 8
},
"NB606": {
"revision": 1,
"explanation": "A 48 W load at 12 V draws $I = P/U = 48/12 = 4 A$.",
"source": "IEC 60050 International Electrotechnical Vocabulary",
"confidence": 8
},
"NB701": {
"revision": 1,
"explanation": "The open contact in the shown schematic is the conventional symbol for a switch.",
"source": "IEC 60617 graphical symbols for diagrams",
"confidence": 7
},
"NB702": {
"revision": 1,
"explanation": "Technical current direction is defined from the positive terminal through the external circuit toward the negative terminal.",
"source": "IEC 60050 International Electrotechnical Vocabulary",
"confidence": 7
},
"NB703": {
"revision": 2,
"explanation": "An LED lights only when the circuit is closed and the diode is forward-biased with current flowing through it.",
"source": "https://50ohm.de/N_slide_n_bauteile_und_schaltkreise.html",
"confidence": 7
},
"NC101": {
"revision": 1,
"explanation": "The zig-zag or rectangular two-terminal schematic element is the conventional resistor symbol.",
"source": "IEC 60617 graphical symbols for diagrams",
"confidence": 7
},
"NC102": {
"revision": 1,
"explanation": "In the resistor colour code, green as the multiplier band means $10^5$, or 100000.",
"source": "IEC 60062 marking codes for resistors and capacitors",
"confidence": 8
},
"NC103": {
"revision": 1,
"explanation": "For 1.2 kOhm, the first two digits are 1 and 2, brown and red, and the multiplier is $10^2$, red.",
"source": "IEC 60062 marking codes for resistors and capacitors",
"confidence": 8
},
"NC104": {
"revision": 1,
"explanation": "Red and violet give the digits 2 and 7; a red multiplier is $10^2$, so the value is $27 \\cdot 100 = 2700$ ohm, or 2.7 kOhm.",
"source": "IEC 60062 marking codes for resistors and capacitors",
"confidence": 8
},
"NC105": {
"revision": 1,
"explanation": "Yellow and violet give 4 and 7; a red multiplier is $10^2$, so the value is 4700 ohm or 4.7 kOhm.",
"source": "IEC 60062 marking codes for resistors and capacitors",
"confidence": 8
},
"NC106": {
"revision": 1,
"explanation": "Red and violet give 27; an orange multiplier is $10^3$, so the value is 27000 ohm or 27 kOhm.",
"source": "IEC 60062 marking codes for resistors and capacitors",
"confidence": 8
},
"NC107": {
"revision": 1,
"explanation": "Yellow and violet give 47; an orange multiplier is $10^3$, so the value is 47000 ohm or 47 kOhm.",
"source": "IEC 60062 marking codes for resistors and capacitors",
"confidence": 8
},
"NC108": {
"revision": 1,
"explanation": "In the resistor tolerance colour code, silver denotes a tolerance of plus or minus 10 percent.",
"source": "IEC 60062 marking codes for resistors and capacitors",
"confidence": 8
},
"NC109": {
"revision": 1,
"explanation": "In the resistor tolerance colour code, gold denotes a tolerance of plus or minus 5 percent.",
"source": "IEC 60062 marking codes for resistors and capacitors",
"confidence": 8
},
"NC110": {
"revision": 1,
"explanation": "In the resistor tolerance colour code, brown denotes a tolerance of plus or minus 1 percent.",
"source": "IEC 60062 marking codes for resistors and capacitors",
"confidence": 8
},
"NC201": {
"revision": 1,
"explanation": "Two separated plates in the schematic symbol represent a capacitor, because a capacitor stores charge between two conductors.",
"source": "IEC 60617 graphical symbols for diagrams",
"confidence": 7
},
"NC301": {
"revision": 1,
"explanation": "The looped or coiled schematic element is the conventional symbol for an inductor or coil.",
"source": "IEC 60617 graphical symbols for diagrams",
"confidence": 7
},
"NC401": {
"revision": 1,
"explanation": "A diode symbol shows a one-way junction; current flows conventionally from anode toward cathode when forward-biased.",
"source": "IEC 60617 graphical symbols for diagrams",
"confidence": 7
},
"NC402": {
"revision": 1,
"explanation": "A light-emitting diode is drawn as a diode with arrows showing emitted light.",
"source": "IEC 60617 graphical symbols for diagrams",
"confidence": 7
},
"NC403": {
"revision": 1,
"explanation": "The diode terminal at the triangle side is the anode, and the terminal at the bar side is the cathode.",
"source": "IEC 60617 graphical symbols for diagrams",
"confidence": 7
},
"NC404": {
"revision": 2,
"explanation": "Current flows through a diode circuit only when the diode is forward-biased and the loop is closed.",
"source": "https://50ohm.de/N_slide_n_bauteile_und_schaltkreise.html",
"confidence": 7
},
"NC501": {
"revision": 1,
"explanation": "A transistor symbol has three terminals for controlling current through the device, unlike two-terminal passive components.",
"source": "IEC 60617 graphical symbols for diagrams",
"confidence": 7
},
"ND101": {
"revision": 2,
"explanation": "A mains power supply converts 230 V AC from the wall outlet into the DC voltage a mobile transceiver needs.",
"source": "https://50ohm.de/N_netzgeraet_1.html",
"confidence": 7
},
"ND102": {
"revision": 3,
"explanation": "Mobile amateur transceivers are normally designed for vehicle electrical systems, so an external supply is usually around 13.8 V DC.",
"source": "https://50ohm.de/N_netzgeraet_1.html",
"confidence": 7
},
"ND103": {
"revision": 2,
"explanation": "A complete DC circuit needs an outgoing and a return conductor, so current leaves through one lead and returns through the other.",
"source": "https://50ohm.de/N_netzgeraet_1.html",
"confidence": 7
},
"ND104": {
"revision": 2,
"explanation": "The two conductors complete the current path through the transceiver; without the return lead the circuit is open.",
"source": "https://50ohm.de/N_netzgeraet_1.html",
"confidence": 7
},
"ND105": {
"revision": 3,
"explanation": "DC equipment conventionally marks the positive lead red and the negative lead black to reduce polarity mistakes.",
"source": "https://50ohm.de/N_netzgeraet_1.html",
"confidence": 7
},
"ND106": {
"revision": 3,
"explanation": "Transceivers are polarity-sensitive DC loads, so reversing plus and minus can put voltage on the wrong internal circuitry.",
"source": "https://50ohm.de/N_netzgeraet_1.html",
"confidence": 7
},
"ND107": {
"revision": 3,
"explanation": "Reverse polarity can drive current through protection parts or semiconductor junctions in the wrong direction and damage the radio.",
"source": "https://50ohm.de/N_netzgeraet_1.html",
"confidence": 7
},
"ND108": {
"revision": 3,
"explanation": "Current limiting protects against short circuits, and thermal shutdown protects the supply when internal heating becomes excessive.",
"source": "https://50ohm.de/N_netzgeraet_1.html",
"confidence": 7
},
"ND109": {
"revision": 2,
"explanation": "The protective contact connects exposed conductive parts to the protective-earth conductor so fault current can be carried safely away.",
"source": "https://publikationen.dguv.de/regelwerk/dguv-informationen/284/sicherheit-bei-arbeiten-an-elektrischen-anlagen",
"confidence": 8
},
"ND110": {
"revision": 2,
"explanation": "A short circuit can make batteries or accumulators deliver very high current, causing heat, fire risk or cell damage.",
"source": "https://publikationen.dguv.de/regelwerk/dguv-informationen/284/sicherheit-bei-arbeiten-an-elektrischen-anlagen",
"confidence": 7
},
"ND201": {
"revision": 1,
"explanation": "An oscillator is a circuit that generates a periodic electrical signal without needing an external signal of that frequency.",
"source": "IEC 60050 International Electrotechnical Vocabulary",
"confidence": 7
},
"NE101": {
"revision": 2,
"explanation": "Modulation varies a carrier in a controlled way so information can be transported by the radio-frequency signal.",
"source": "https://50ohm.de/N_rauch_und_morsezeichen.html",
"confidence": 7
},
"NE102": {
"revision": 2,
"explanation": "SSB, FM and AM are all modulation methods; the distractors mix in bands, equipment names or operating procedures.",
"source": "https://50ohm.de/NE_trxmodulation.html",
"confidence": 7
},
"NE201": {
"revision": 2,
"explanation": "CW conveys information by keying a continuous RF carrier on and off, which forms the Morse elements.",
"source": "https://50ohm.de/N_rauch_und_morsezeichen.html",
"confidence": 7
},
"NE202": {
"revision": 2,
"explanation": "In amplitude modulation, the carrier amplitude follows the information signal while the carrier frequency ideally stays fixed.",
"source": "https://50ohm.de/NE_am.html",
"confidence": 7
},
"NE203": {
"revision": 2,
"explanation": "Ordinary AM transmits a carrier plus both sidebands; SSB suppresses the carrier and one sideband to save bandwidth and power.",
"source": "https://50ohm.de/NE_ssb.html",
"confidence": 7
},
"NE204": {
"revision": 2,
"explanation": "LSB and USB are the lower and upper sideband versions of SSB; both suppress the carrier but keep opposite sides of the spectrum.",
"source": "https://50ohm.de/NE_ssb.html",
"confidence": 7
},
"NE205": {
"revision": 2,
"explanation": "In an AM spectrum, the lower sideband lies below the carrier and the upper sideband lies above it.",
"source": "https://50ohm.de/NE_ssb.html",
"confidence": 7
},
"NE206": {
"revision": 2,
"explanation": "AM produces two mirror sidebands around the carrier, so the correct spectrum contains both LSB and USB for the audio content.",
"source": "https://50ohm.de/NE_am.html",
"confidence": 7
},
"NE207": {
"revision": 2,
"explanation": "USB keeps the sideband above the carrier, with audio-frequency components translated upward in frequency.",
"source": "https://50ohm.de/NE_ssb.html",
"confidence": 7
},
"NE208": {
"revision": 2,
"explanation": "LSB keeps the sideband below the carrier, so the audio spectrum appears on the lower-frequency side.",
"source": "https://50ohm.de/NE_ssb.html",
"confidence": 7
},
"NE209": {
"revision": 2,
"explanation": "USB is the upper-sideband mode of SSB, meaning the receiver demodulates only the sideband above the suppressed carrier frequency.",
"source": "https://50ohm.de/NE_trxmodulation.html",
"confidence": 7
},
"NE210": {
"revision": 2,
"explanation": "The 2 m amateur SSB convention uses upper sideband, so the transceiver mode must be USB.",
"source": "https://50ohm.de/NE_trxmodulation.html",
"confidence": 7
},
"NE211": {
"revision": 2,
"explanation": "On 80 m, amateur SSB voice conventionally uses lower sideband, so the receiver mode is LSB.",
"source": "https://50ohm.de/NE_trxmodulation.html",
"confidence": 7
},
"NE212": {
"revision": 2,
"explanation": "SSB speech depends on the correct sideband and precise tuning; checking sideband mode and tuning the VFO addresses both causes.",
"source": "https://50ohm.de/NE_trxmodulation.html",
"confidence": 7
},
"NE301": {
"revision": 2,
"explanation": "In frequency modulation, the information signal varies the carrier frequency while the carrier amplitude ideally remains constant.",
"source": "https://50ohm.de/NEA_fm.html",
"confidence": 7
},
"NE302": {
"revision": 2,
"explanation": "FM is defined by varying a carrier's frequency according to the signal being transmitted.",
"source": "https://50ohm.de/NEA_fm.html",
"confidence": 7
},
"NE303": {
"revision": 2,
"explanation": "FM information is carried by frequency deviation, so the RF amplitude is ideally unaffected by microphone audio.",
"source": "https://50ohm.de/NEA_fm.html",
"confidence": 7
},
"NE304": {
"revision": 2,
"explanation": "In ideal FM the transmitter output power is essentially constant; speaking louder changes deviation, not the set RF power.",
"source": "https://50ohm.de/NEA_fm.html",
"confidence": 7
},
"NE305": {
"revision": 2,
"explanation": "A 15 kHz-wide emission extends about half its bandwidth on each side of the centre frequency, so it needs at least 7.5 kHz clearance.",
"source": "https://50ohm.de/NE_bandbreite.html",
"confidence": 7
},
"NE306": {
"revision": 2,
"explanation": "Too much FM deviation usually comes from excessive audio level, so speaking more quietly reduces the modulation hub.",
"source": "https://50ohm.de/NEA_fm.html",
"confidence": 7
},
"NE307": {
"revision": 2,
"explanation": "Handheld VHF/UHF amateur radios commonly support analogue FM and digital voice systems such as DMR and D-STAR.",
"source": "https://50ohm.de/N_digital_voice.html",
"confidence": 7
},
"NE308": {
"revision": 2,
"explanation": "Voice repeaters on VHF/UHF commonly carry analogue FM and digital voice modes such as DMR and D-STAR.",
"source": "https://50ohm.de/N_relaisfunkstellen.html",
"confidence": 7
},
"NE309": {
"revision": 2,
"explanation": "Analogue amateur voice repeaters on VHF/UHF conventionally use FM because it is robust for local line-of-sight voice links.",
"source": "https://50ohm.de/N_relaisfunkstellen.html",
"confidence": 7
},
"NE310": {
"revision": 2,
"explanation": "An FM receiver cannot cleanly demodulate two equal-strength co-channel signals at once, so simultaneous relay input signals interfere badly.",
"source": "https://50ohm.de/N_relaisfunkstellen.html",
"confidence": 7
},
"NE401": {
"revision": 2,
"explanation": "Digital text modes only interoperate when both stations use the same waveform and parameters such as speed, tone spacing or protocol settings.",
"source": "https://50ohm.de/N_funkfernschreiben.html",
"confidence": 7
},
"NE402": {
"revision": 2,
"explanation": "Digital voice repeater networks need more than frequency and mode; routing parameters such as reflector, time slot or colour code select the intended network path.",
"source": "https://50ohm.de/N_digital_voice.html",
"confidence": 7
},
"NE403": {
"revision": 2,
"explanation": "Time-division systems carry separate conversations in alternating time slots, allowing more than one channel on the same RF frequency.",
"source": "https://50ohm.de/N_digital_voice.html",
"confidence": 7
},
"NE404": {
"revision": 2,
"explanation": "DMR, D-STAR, C4FM, M17 and FreeDV are amateur digital voice systems, unlike analogue-only or non-voice modes.",
"source": "https://50ohm.de/N_digital_voice.html",
"confidence": 7
},
"NE405": {
"revision": 2,
"explanation": "Link paths are fixed radio links used as infrastructure, for example to connect repeaters with each other or to HAMNET nodes.",
"source": "https://50ohm.de/N_slide_n_amateurfunkstationen.html",
"confidence": 7
},
"NF101": {
"revision": 2,
"explanation": "SWR indication reports the antenna matching condition during transmit, so display item 1 is the SWR meter.",
"source": "https://50ohm.de/N_swr.html",
"confidence": 7
},
"NF102": {
"revision": 2,
"explanation": "In transmit mode, a power meter display shows the RF output power being delivered by the transceiver.",
"source": "https://50ohm.de/N_ausgangsleistung.html",
"confidence": 7
},
"NF103": {
"revision": 2,
"explanation": "An S-meter indicates received signal strength, so it is the relevant receive-level display.",
"source": "https://50ohm.de/N_slide_n_erste_schritte.html",
"confidence": 7
},
"NF104": {
"revision": 2,
"explanation": "An amplitude spectrum shows signal strength versus frequency, which matches display item 3.",
"source": "https://50ohm.de/N_wasserfall.html",
"confidence": 7
},
"NF105": {
"revision": 2,
"explanation": "A waterfall diagram adds time to the spectrum display, with newer signal traces appearing as coloured or bright lines.",
"source": "https://50ohm.de/N_wasserfall.html",
"confidence": 7
},
"NF106": {
"revision": 2,
"explanation": "A waterfall plot uses one axis for frequency, one for time, and colour or brightness for received signal strength.",
"source": "https://50ohm.de/N_wasserfall.html",
"confidence": 7
},
"NF107": {
"revision": 2,
"explanation": "A mismatched or missing load reflects RF power back toward the transmitter, which can overheat or damage the final amplifier.",
"source": "https://50ohm.de/N_dummy_load_1.html",
"confidence": 7
},
"NF108": {
"revision": 2,
"explanation": "PTT means push-to-talk: pressing the microphone switch keys the transmitter.",
"source": "https://50ohm.de/N_erste_schritte.html",
"confidence": 7
},
"NF109": {
"revision": 2,
"explanation": "VOX is voice-operated transmit control, where microphone audio automatically keys the transmitter.",
"source": "https://50ohm.de/N_slide_n_transceiver.html",
"confidence": 7
},
"NF110": {
"revision": 2,
"explanation": "If VOX is enabled, room noise or microphone audio can key the transmitter without pressing PTT.",
"source": "https://50ohm.de/N_slide_n_transceiver.html",
"confidence": 7
},
"NF111": {
"revision": 2,
"explanation": "RIT changes only the receive frequency, letting you clarify the other station without moving your transmit frequency.",
"source": "https://50ohm.de/NE_rit.html",
"confidence": 7
},
"NF112": {
"revision": 2,
"explanation": "With RIT active, receive and transmit can be offset; the operator may tune reception while transmitting on a slightly different frequency.",
"source": "https://50ohm.de/NE_rit.html",
"confidence": 7
},
"NF113": {
"revision": 2,
"explanation": "Using different uplink and downlink bands makes filtering easier because the satellite can separate its receiver and transmitter signals more effectively.",
"source": "https://50ohm.de/N_slide_n_amateurfunkstationen.html",
"confidence": 7
},
"NF114": {
"revision": 2,
"explanation": "Digital modes need baseband audio or data between computer and radio, either by an audio/USB interface or by a modem that performs that conversion.",
"source": "https://50ohm.de/NE_computersteuerung.html",
"confidence": 7
},
"NF115": {
"revision": 2,
"explanation": "A data connector bypasses audio shaping intended for speech, giving digital signals a cleaner path into or out of the FM transceiver.",
"source": "https://50ohm.de/NE_computersteuerung.html",
"confidence": 7
},
"NF116": {
"revision": 2,
"explanation": "CAT control is a serial command interface used to read and set radio functions such as frequency, power and PTT from a computer.",
"source": "https://50ohm.de/NE_computersteuerung.html",
"confidence": 7
},
"NF117": {
"revision": 2,
"explanation": "Computer control can assert PTT or change settings unexpectedly, so it can create unintended transmissions or safety hazards if not supervised.",
"source": "https://50ohm.de/NE_computersteuerung.html",
"confidence": 7
},
"NF118": {
"revision": 2,
"explanation": "A digipeater is a digital relay: it receives packet data and retransmits it, possibly after updating fields such as routing information.",
"source": "https://50ohm.de/N_slide_n_amateurfunkstationen.html",
"confidence": 7
},
"NF201": {
"revision": 2,
"explanation": "The block diagram is a receiver because the signal path runs from antenna input through receiving stages toward audio or data output.",
"source": "https://50ohm.de/N_slide_n_transceiver.html",
"confidence": 7
},
"NF301": {
"revision": 2,
"explanation": "The S-meter gives the operator a relative indication of received signal level.",
"source": "https://50ohm.de/N_slide_n_transceiver.html",
"confidence": 7
},
"NF302": {
"revision": 2,
"explanation": "Squelch mutes the receiver audio until a signal exceeds the set threshold, hiding FM noise when no useful signal is present.",
"source": "https://50ohm.de/N_slide_n_transceiver.html",
"confidence": 7
},
"NF303": {
"revision": 2,
"explanation": "Receiver sensitivity describes how weak a signal the receiver can still detect or demodulate usefully.",
"source": "https://50ohm.de/N_slide_n_transceiver.html",
"confidence": 7
},
"NF401": {
"revision": 2,
"explanation": "The block diagram is a transmitter because the signal path builds an RF signal and delivers it toward the antenna output.",
"source": "https://50ohm.de/N_slide_n_transceiver.html",
"confidence": 7
},
"NF402": {
"revision": 2,
"explanation": "A simple transmitter generates RF, combines it with modulation, filters unwanted products, and amplifies the wanted signal.",
"source": "https://50ohm.de/N_slide_n_transceiver.html",
"confidence": 7
},
"NF403": {
"revision": 2,
"explanation": "The stages follow the usual transmitter chain: audio amplification, mixing with an RF oscillator, filtering, RF amplification, and final filtering.",
"source": "https://50ohm.de/N_slide_n_transceiver.html",
"confidence": 7
},
"NF404": {
"revision": 2,
"explanation": "A transmitter output filter should pass the wanted VHF band while attenuating unwanted frequencies outside it.",
"source": "https://50ohm.de/NE_slide_ne_sender.html",
"confidence": 7
},
"NG101": {
"revision": 1,
"explanation": "The shown schematic symbol represents an antenna connection, the point where RF energy is radiated or received.",
"source": "IEC 60617 graphical symbols for diagrams",
"confidence": 7
},
"NG102": {
"revision": 1,
"explanation": "The ground symbol marks an earth connection or earth reference in the antenna diagram.",
"source": "IEC 60617 graphical symbols for diagrams",
"confidence": 7
},
"NG103": {
"revision": 2,
"explanation": "A dipole has two arms fed near the centre, which is the configuration shown.",
"source": "https://50ohm.de/N_dipol.html",
"confidence": 7
},
"NG104": {
"revision": 2,
"explanation": "A Marconi antenna is a quarter-wave vertical worked against earth or a counterpoise, so it is a $\\lambda/4$ vertical antenna.",
"source": "https://50ohm.de/N_rundstrahler.html",
"confidence": 7
},
"NG105": {
"revision": 2,
"explanation": "A ground-plane antenna is a vertical radiator with radial conductors forming the counterpoise, matching the shown structure.",
"source": "https://50ohm.de/N_rundstrahler.html",
"confidence": 7
},
"NG106": {
"revision": 2,
"explanation": "The conductors that provide the counterpoise for a ground-plane antenna are called radials.",
"source": "https://50ohm.de/N_rundstrahler.html",
"confidence": 7
},
"NG107": {
"revision": 2,
"explanation": "An end-fed antenna is fed at one end rather than at the centre, which matches the depicted arrangement.",
"source": "https://50ohm.de/N_endgespeiste_antennen.html",
"confidence": 7
},
"NG108": {
"revision": 2,
"explanation": "A Yagi-Uda antenna uses a driven element with parasitic reflector and director elements on a boom, matching the shown directional antenna.",
"source": "https://50ohm.de/N_yagi_uda_1.html",
"confidence": 7
},
"NG109": {
"revision": 2,
"explanation": "Long-wire antennas are practical mainly on HF; at VHF/UHF their physical size and radiation behaviour make other antenna types usual.",
"source": "https://50ohm.de/N_endgespeiste_antennen.html",
"confidence": 7
},
"NG110": {
"revision": 2,
"explanation": "For a local round with stations in several directions, an omnidirectional antenna avoids aiming a directional beam at each station.",
"source": "https://50ohm.de/N_rundstrahler.html",
"confidence": 7
},
"NG111": {
"revision": 2,
"explanation": "Repeaters around the station may lie in many directions, so a roof-mounted omnidirectional antenna gives broad azimuth coverage and height.",
"source": "https://50ohm.de/N_rundstrahler.html",
"confidence": 7
},
"NG201": {
"revision": 2,
"explanation": "Common coaxial cable impedances include 50 ohm for transmitting systems and 75 ohm for receiving or video systems; 60 ohm also exists historically.",
"source": "https://50ohm.de/N_uebertragungsleitungen.html",
"confidence": 7
},
"NG202": {
"revision": 2,
"explanation": "The connector shown has the form used by the PL or UHF connector family.",
"source": "IEC 61169 radio-frequency connector series",
"confidence": 6
},
"NG203": {
"revision": 2,
"explanation": "The bayonet-lock form shown is characteristic of a BNC connector.",
"source": "IEC 61169 radio-frequency connector series",
"confidence": 6
},
"NG204": {
"revision": 2,
"explanation": "The threaded RF connector shown is the N connector, widely used at VHF/UHF for lower loss and better impedance control.",
"source": "IEC 61169 radio-frequency connector series",
"confidence": 6
},
"NG205": {
"revision": 2,
"explanation": "The small threaded connector shown is SMA, a compact RF connector commonly used on handhelds and microwave gear.",
"source": "IEC 61169 radio-frequency connector series",
"confidence": 6
},
"NG206": {
"revision": 2,
"explanation": "N and SMA connectors maintain better RF performance above 300 MHz than older connector systems such as PL.",
"source": "IEC 61169 radio-frequency connector series",
"confidence": 7
},
"NG207": {
"revision": 2,
"explanation": "Coaxial-line attenuation accumulates with length and generally rises with frequency, so both matter when choosing VHF/UHF feed line.",
"source": "https://50ohm.de/N_uebertragungsleitungen.html",
"confidence": 7
},
"NG208": {
"revision": 2,
"explanation": "Extra coax adds loss in both forward and reflected waves, so the meter can show a lower SWR even though efficiency has worsened.",
"source": "https://50ohm.de/N_swr.html",
"confidence": 7
},
"NG301": {
"revision": 2,
"explanation": "An SWR of 1:1 means no reflected power from mismatch, which is the best possible match.",
"source": "https://50ohm.de/N_swr.html",
"confidence": 8
},
"NG302": {
"revision": 2,
"explanation": "A high SWR-meter indication means significant reflected power, which points to poor antenna or feed-line matching.",
"source": "https://50ohm.de/N_swr.html",
"confidence": 7
},
"NG303": {
"revision": 2,
"explanation": "Mismatch or damage changes the line impedance seen by the transmitter, causing RF reflections and therefore a higher SWR.",
"source": "https://50ohm.de/N_swr.html",
"confidence": 7
},
"NG304": {
"revision": 2,
"explanation": "A dipole that resonates too low is electrically too long; shortening both arms raises its resonant frequency.",
"source": "https://50ohm.de/N_slide_n_antennen_und_leitungen.html",
"confidence": 8
},
"NG305": {
"revision": 2,
"explanation": "A dipole that resonates too high is electrically too short; lengthening both arms lowers its resonant frequency.",
"source": "https://50ohm.de/N_slide_n_antennen_und_leitungen.html",
"confidence": 8
},
"NG401": {
"revision": 2,
"explanation": "ERP is radiated power referenced to a half-wave dipole, not to an isotropic radiator.",
"source": "https://life.itu.int/radioclub/rr/art1.pdf",
"confidence": 8
},
"NG402": {
"revision": 2,
"explanation": "EIRP is radiated power referenced to an ideal isotropic radiator.",
"source": "https://life.itu.int/radioclub/rr/art1.pdf",
"confidence": 8
},
"NH101": {
"revision": 2,
"explanation": "The ionosphere is the ionised upper-atmosphere region that can refract HF radio waves back toward Earth.",
"source": "https://50ohm.de/NEA_ionosphaere.html",
"confidence": 7
},
"NH102": {
"revision": 2,
"explanation": "Free electrons and ions in the ionosphere change the refractive index for radio waves, allowing HF waves to bend rather than travel straight into space.",
"source": "https://50ohm.de/NEA_ionosphaere.html",
"confidence": 7
},
"NH201": {
"revision": 2,
"explanation": "Solar activity controls ionisation density in the ionosphere, and the roughly eleven-year solar cycle therefore strongly affects HF propagation.",
"source": "https://50ohm.de/NEA_ionosphaere.html",
"confidence": 7
},
"NH301": {
"revision": 2,
"explanation": "Standard atmospheric refraction bends VHF paths slightly toward Earth, making the radio horizon about 15 percent beyond the geometric horizon.",
"source": "https://50ohm.de/N_funkhorizont.html",
"confidence": 7
},
"NH302": {
"revision": 2,
"explanation": "VHF coverage is largely line-of-sight; raising the antenna increases the visible radio path over terrain and curvature.",
"source": "https://50ohm.de/N_funkhorizont.html",
"confidence": 7
},
"NH303": {
"revision": 2,
"explanation": "The best VHF path is the station with the clearest quasi-optical path in the terrain profile; in the shown figure that is $\\text{E}_3$.",
"source": "https://50ohm.de/N_funkhorizont.html",
"confidence": 7
},
"NH304": {
"revision": 2,
"explanation": "Tropospheric inversions can form ducts or enhanced refractive layers, allowing VHF signals to travel hundreds of kilometres beyond normal range.",
"source": "https://50ohm.de/N_troposphaere.html",
"confidence": 7
},
"NH305": {
"revision": 2,
"explanation": "Sporadic-E uses dense temporary ionisation patches in the E region, typically around 100 to 110 km altitude.",
"source": "https://50ohm.de/NEA_sporadic_e_1.html",
"confidence": 7
},
"NH306": {
"revision": 2,
"explanation": "On 2 m, Sporadic-E means unusually long VHF paths via refraction in sporadic E-region ionisation, often around 1000 to 2000 km.",
"source": "https://50ohm.de/NEA_sporadic_e_1.html",
"confidence": 7
},
"NI101": {
"revision": 1,
"explanation": "The voltmeter symbol identifies a voltage-measuring instrument, which is connected across the points whose potential difference is measured.",
"source": "IEC 60617 graphical symbols for diagrams",
"confidence": 7
},
"NI102": {
"revision": 1,
"explanation": "The ammeter symbol identifies a current-measuring instrument, which is inserted in series with the current path.",
"source": "IEC 60617 graphical symbols for diagrams",
"confidence": 7
},
"NI103": {
"revision": 2,
"explanation": "Voltage is measured in parallel with the battery, so the meter must be connected across the battery while the circuit remains operating.",
"source": "https://50ohm.de/N_spannungsmessung.html",
"confidence": 7
},
"NI104": {
"revision": 2,
"explanation": "Current through a component is measured in series, so the meter must be inserted into the path through the resistor and LED.",
"source": "https://50ohm.de/N_spannungsmessung.html",
"confidence": 7
},
"NI201": {
"revision": 2,
"explanation": "A standing-wave meter compares forward and reflected RF power, which is how antenna matching is inferred.",
"source": "https://50ohm.de/N_swr.html",
"confidence": 7
},
"NI202": {
"revision": 2,
"explanation": "To measure reflections in the antenna system, the SWR meter is inserted between the transceiver and antenna, with the transmitter on the other port.",
"source": "https://50ohm.de/N_swr.html",
"confidence": 7
},
"NI203": {
"revision": 2,
"explanation": "An ideal match has no reflected wave, so the SWR meter should read 1:1.",
"source": "https://50ohm.de/N_swr.html",
"confidence": 8
},
"NI301": {
"revision": 2,
"explanation": "A frequency counter measures the frequency of an electrical signal directly, so it is the appropriate instrument for transmitter frequency.",
"source": "https://50ohm.de/N_frequenz.html",
"confidence": 7
},
"NI401": {
"revision": 2,
"explanation": "An oscillogram is time-domain display; an amplitude spectrum is frequency-domain display showing the signal components by frequency.",
"source": "https://50ohm.de/N_wasserfall.html",
"confidence": 8
},
"NJ101": {
"revision": 2,
"explanation": "Shielding confines RF currents and fields, reducing unwanted coupling into nearby equipment or wiring.",
"source": "https://50ohm.de/NE_elektromagnetische_vertraeglichkeit.html",
"confidence": 7
},
"NJ102": {
"revision": 2,
"explanation": "Interference complaints should be handled cooperatively; arranging checks can identify whether the cause is the amateur station, the affected device or the installation.",
"source": "https://50ohm.de/NE_elektromagnetische_vertraeglichkeit.html",
"confidence": 7
},
"NJ201": {
"revision": 2,
"explanation": "Unwanted emissions waste spectrum and may interfere with other services, so a transmitter must be adjusted and filtered to avoid them.",
"source": "https://50ohm.de/NE_slide_ne_sender.html",
"confidence": 7
},
"NJ202": {
"revision": 3,
"explanation": "A dummy load provides a non-radiating matched load, letting you align the transmitter without putting test signals on the air.",
"source": "https://50ohm.de/N_dummy_load_1.html",
"confidence": 7
},
"NK101": {
"revision": 2,
"explanation": "Shielding HF stages reduces radiation and susceptibility by keeping RF energy inside the intended circuit region.",
"source": "https://50ohm.de/NE_elektromagnetische_vertraeglichkeit.html",
"confidence": 7
},
"NK102": {
"revision": 2,
"explanation": "A good RF earth gives unwanted RF currents a controlled return path and reduces coupling into equipment, cables and surroundings.",
"source": "https://50ohm.de/NE_elektromagnetische_vertraeglichkeit.html",
"confidence": 7
},
"NK201": {
"revision": 2,
"explanation": "Near antennas, electromagnetic fields can exceed exposure limits; operators need enough knowledge to keep people outside unsafe field strengths.",
"source": "https://publikationen.dguv.de/regelwerk/dguv-informationen/284/sicherheit-bei-arbeiten-an-elektrischen-anlagen",
"confidence": 7
},
"NK301": {
"revision": 2,
"explanation": "Common electrical-safety practice treats contact above 50 V AC or 120 V DC as hazardous under normal dry conditions.",
"source": "https://publikationen.dguv.de/regelwerk/dguv-informationen/284/sicherheit-bei-arbeiten-an-elektrischen-anlagen",
"confidence": 8
},
"NK302": {
"revision": 2,
"explanation": "The main electrical hazards are current through the body, arc faults, and secondary accidents such as falls caused by shock or startle.",
"source": "https://publikationen.dguv.de/regelwerk/dguv-informationen/284/sicherheit-bei-arbeiten-an-elektrischen-anlagen",
"confidence": 8
},
"NK303": {
"revision": 2,
"explanation": "Body current can heat tissue, force muscles to contract, and disturb the heart rhythm, including dangerous fibrillation.",
"source": "https://publikationen.dguv.de/regelwerk/dguv-informationen/284/sicherheit-bei-arbeiten-an-elektrischen-anlagen",
"confidence": 8
},
"NK304": {
"revision": 2,
"explanation": "Heart rhythm disturbances can be delayed after an electric shock, so medical assessment is required even when the person initially feels well.",
"source": "https://publikationen.dguv.de/regelwerk/dguv-informationen/284/sicherheit-bei-arbeiten-an-elektrischen-anlagen",
"confidence": 8
},
"NK305": {
"revision": 2,
"explanation": "A fuse protects only as designed when its current rating and time-current characteristic match the original device.",
"source": "https://publikationen.dguv.de/regelwerk/dguv-informationen/284/sicherheit-bei-arbeiten-an-elektrischen-anlagen",
"confidence": 8
},
"NK306": {
"revision": 2,
"explanation": "Rechargeable batteries can deliver high energy and contain reactive chemicals, so misuse can cause burns, chemical injury or toxic exposure.",
"source": "https://publikationen.dguv.de/regelwerk/dguv-informationen/284/sicherheit-bei-arbeiten-an-elektrischen-anlagen",
"confidence": 7
},
"NK307": {
"revision": 2,
"explanation": "A vehicle battery can supply very high short-circuit current; wrong connection can create arcs and ignite wiring or surrounding material.",
"source": "https://50ohm.de/NEA_einbau_kfz.html",
"confidence": 7
},
"NK308": {
"revision": 2,
"explanation": "Vehicle electronics and approval conditions depend on manufacturer installation limits, so those instructions govern radio installation.",
"source": "https://50ohm.de/NEA_einbau_kfz.html",
"confidence": 7
},
"NK309": {
"revision": 2,
"explanation": "Keeping coax away from vehicle wiring reduces RF coupling into control electronics and avoids parallel runs acting as coupled lines.",
"source": "https://50ohm.de/NEA_einbau_kfz.html",
"confidence": 7
},
"NK310": {
"revision": 2,
"explanation": "The centre of a metal roof gives a VHF mobile antenna a good ground plane and a more even radiation pattern around the car.",
"source": "https://50ohm.de/NEA_einbau_kfz.html",
"confidence": 7
},
"NK311": {
"revision": 2,
"explanation": "Antenna parts must be arranged so that failure cannot bring conductive parts into contact with power lines, where lethal voltages may be present.",
"source": "https://publikationen.dguv.de/regelwerk/dguv-informationen/284/sicherheit-bei-arbeiten-an-elektrischen-anlagen",
"confidence": 8
},
"VA101": {
"revision": 1,
"explanation": "The international definition is in the ITU Radio Regulations, which define radio services globally before national rules implement them.",
"source": "https://www.itu.int/pub/R-REG-RR",
"confidence": 9
},
"VA102": {
"revision": 1,
"explanation": "RR Article 1 defines the amateur service as self-training, intercommunication and technical investigation by authorised amateurs.",
"source": "https://www.itu.int/pub/R-REG-RR",
"confidence": 9
},
"VA103": {
"revision": 1,
"explanation": "The amateur-satellite service is the same amateur service carried through space stations, so its purposes stay the same.",
"source": "https://www.itu.int/pub/R-REG-RR",
"confidence": 9
},
"VA104": {
"revision": 1,
"explanation": "The RR definition limits amateur operators to duly authorised persons interested in radio technique solely with a personal aim and without pecuniary interest.",
"source": "https://www.itu.int/pub/R-REG-RR",
"confidence": 9
},
"VA201": {
"revision": 1,
"explanation": "In the RR, a station is the transmitters, receivers and accessories needed at one place to carry out a radiocommunication service.",
"source": "https://www.itu.int/pub/R-REG-RR",
"confidence": 9
},
"VA202": {
"revision": 1,
"explanation": "An amateur station is simply a station in the amateur service, so the service definition determines the station type.",
"source": "https://www.itu.int/pub/R-REG-RR",
"confidence": 9
},
"VA301": {
"revision": 1,
"explanation": "The Radio Regulations' general rules apply to all radiocommunication services unless a special rule says otherwise, so amateur radio is included.",
"source": "https://www.itu.int/pub/R-REG-RR",
"confidence": 9
},
"VA302": {
"revision": 1,
"explanation": "RR Article 25 restricts international amateur traffic to amateur-service purposes and personal remarks, excluding third-party business traffic.",
"source": "https://www.itu.int/pub/R-REG-RR",
"confidence": 9
},
"VA303": {
"revision": 1,
"explanation": "RR Article 25 forbids secrecy in amateur traffic but permits encrypted control signals for amateur-satellite control links.",
"source": "https://www.itu.int/pub/R-REG-RR",
"confidence": 9
},
"VA304": {
"revision": 1,
"explanation": "RR Article 25 leaves Morse-code requirements to each national administration, so Germany can decide its own examination rules.",
"source": "https://www.itu.int/pub/R-REG-RR",
"confidence": 9
},
"VA401": {
"revision": 1,
"explanation": "The RR divides the world into regions because frequency allocations differ by region.",
"source": "https://www.itu.int/pub/R-REG-RR",
"confidence": 9
},
"VA402": {
"revision": 1,
"explanation": "The RR allocation table is organised into three ITU regions.",
"source": "https://www.itu.int/pub/R-REG-RR",
"confidence": 9
},
"VA403": {
"revision": 1,
"explanation": "Germany is in ITU Region 1, the region covering Europe, Africa and parts of western Asia.",
"source": "https://www.itu.int/pub/R-REG-RR",
"confidence": 9
},
"VA404": {
"revision": 1,
"explanation": "Canada is in ITU Region 2, the region covering the Americas.",
"source": "https://www.itu.int/pub/R-REG-RR",
"confidence": 9
},
"VA405": {
"revision": 1,
"explanation": "Australia is in ITU Region 3, the region covering Asia-Pacific outside the Region 1/2 areas.",
"source": "https://www.itu.int/pub/R-REG-RR",
"confidence": 9
},
"VA406": {
"revision": 1,
"explanation": "International call-sign prefixes are allocated in the Radio Regulations call-sign series table.",
"source": "https://www.itu.int/gladapp/Allocation/CallSigns",
"confidence": 9
},
"VA407": {
"revision": 1,
"explanation": "The Q code meanings are an ITU operating-code item, so the RR is the authoritative international reference.",
"source": "https://www.itu.int/pub/R-REG-RR",
"confidence": 8
},
"VB101": {
"revision": 1,
"explanation": "The CEPT Novice certificate documents a recognised novice-level exam and can simplify getting an equivalent novice individual licence abroad.",
"source": "https://docdb.cept.org/download/2768",
"confidence": 9
},
"VB102": {
"revision": 1,
"explanation": "HAREC is the harmonised CEPT examination certificate under T/R 61-02; German class A matches that level.",
"source": "https://docdb.cept.org/download/2565",
"confidence": 9
},
"VB103": {
"revision": 1,
"explanation": "A HAREC certifies a passed class-A-level exam and is used by participating administrations when issuing a local amateur licence.",
"source": "https://docdb.cept.org/download/2565",
"confidence": 9
},
"VB104": {
"revision": 1,
"explanation": "T/R 61-01 covers temporary guest operation, T/R 61-02 and ERC Report 32 harmonise exam evidence, and ECC (05)06 covers novice operation.",
"source": "https://docdb.cept.org/download/3321",
"confidence": 8
},
"VB105": {
"revision": 1,
"explanation": "Class N is a German national class and is not covered by the CEPT visitor recommendations, so it gives no CEPT operating privilege abroad.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"VB106": {
"revision": 1,
"explanation": "CEPT Novice operation only works in countries that have implemented ECC Recommendation (05)06 and only for temporary stays without residence there.",
"source": "https://docdb.cept.org/download/2768",
"confidence": 9
},
"VB107": {
"revision": 1,
"explanation": "Class A relies on T/R 61-01; the right exists only in countries that implement that recommendation and for temporary non-resident operation.",
"source": "https://docdb.cept.org/download/3321",
"confidence": 9
},
"VB108": {
"revision": 1,
"explanation": "Some non-CEPT countries also accept T/R 61-01 or ECC (05)06, so German A/E operators may operate there when that country has implemented the relevant recommendation.",
"source": "https://docdb.cept.org/download/3321",
"confidence": 8
},
"VB109": {
"revision": 1,
"explanation": "CEPT guest operation is temporary; T/R 61-01 uses a stay of up to three months as the normal limit.",
"source": "https://docdb.cept.org/download/3321",
"confidence": 9
},
"VB110": {
"revision": 1,
"explanation": "Germany's CEPT visitor prefixes are class-dependent: full CEPT visitors use DL/ and novice visitors use DO/ before the home call sign.",
"source": "https://docdb.cept.org/download/3321",
"confidence": 9
},
"VB111": {
"revision": 1,
"explanation": "CEPT operation does not export German privileges; the visitor must follow the CEPT recommendation plus the host country's power, band and operating limits.",
"source": "https://docdb.cept.org/download/3321",
"confidence": 9
},
"VB112": {
"revision": 1,
"explanation": "A German licence does not automatically authorise 6 m abroad; the host country's CEPT implementation and national band limits control.",
"source": "https://docdb.cept.org/download/3321",
"confidence": 9
},
"VB113": {
"revision": 1,
"explanation": "Without CEPT implementation there is no automatic visitor privilege, so the operator needs a guest authorisation from the visited country.",
"source": "https://docdb.cept.org/download/3321",
"confidence": 9
},
"VB114": {
"revision": 1,
"explanation": "T/R 61-01 is for individual visitor operation, not moving a German club station abroad; a club station needs a separate guest authorisation.",
"source": "https://docdb.cept.org/download/3321",
"confidence": 8
},
"VC101": {
"revision": 2,
"explanation": "The AFuG is the German statutory basis for who may participate in the amateur service and under what conditions.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__1.html",
"confidence": 10
},
"VC102": {
"revision": 1,
"explanation": "AFuG §2 defines amateur radio as amateur-to-amateur communication plus experimentation, self-training, international understanding and support of relief actions.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__2.html",
"confidence": 10
},
"VC103": {
"revision": 1,
"explanation": "AFuG §2 defines an amateur station by its transmitters, receivers, antennas and required accessories, capable of operating on amateur frequencies.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__2.html",
"confidence": 10
},
"VC104": {
"revision": 2,
"explanation": "AFuG assigns the law's administrative tasks to the Bundesnetzagentur.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__10.html",
"confidence": 9
},
"VC105": {
"revision": 1,
"explanation": "AFuG §2 defines a radio amateur as the holder of an amateur certificate or harmonised examination certificate.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__2.html",
"confidence": 10
},
"VC106": {
"revision": 1,
"explanation": "Passing the exam is not enough for transmitting; AFuG §3 requires admission to participate and a person-bound call sign.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__3.html",
"confidence": 10
},
"VC107": {
"revision": 1,
"explanation": "The admission is person-bound under AFuG §3, so it cannot be lent or transferred to another person.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__3.html",
"confidence": 10
},
"VC108": {
"revision": 1,
"explanation": "AFuG §3 sets the exam/admission requirement but no minimum age requirement.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__3.html",
"confidence": 9
},
"VC109": {
"revision": 2,
"explanation": "AFuG permits amateurs with assigned call signs to operate commercial, home-built or modified transmitters on amateur frequencies.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__5.html",
"confidence": 9
},
"VC110": {
"revision": 1,
"explanation": "AFuG rights attach to frequencies designated for the amateur service; transmitting outside those allocations is not covered.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__3.html",
"confidence": 9
},
"VC111": {
"revision": 1,
"explanation": "AFuG limits amateur traffic to communication with other amateur stations, apart from emergency exceptions.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__5.html",
"confidence": 9
},
"VC112": {
"revision": 1,
"explanation": "Third-party message relay is normally outside amateur radio, but AFuG allows support in emergency and disaster cases.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__5.html",
"confidence": 9
},
"VC113": {
"revision": 1,
"explanation": "AFuG §2 excludes commercial-economic motivation from the definition of a radio amateur.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__2.html",
"confidence": 10
},
"VC114": {
"revision": 1,
"explanation": "AFuG keeps amateur radio non-commercial, so an amateur station may not be operated for commercial-economic purposes.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__5.html",
"confidence": 9
},
"VC115": {
"revision": 1,
"explanation": "Business provision of telecommunications services is outside the amateur service and is expressly not an amateur-station purpose.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__5.html",
"confidence": 9
},
"VC116": {
"revision": 1,
"explanation": "A person-bound amateur call sign is assigned by BNetzA; using another person-bound call sign would defeat that identification rule.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__3.html",
"confidence": 9
},
"VC117": {
"revision": 1,
"explanation": "AFuG allows call signs to be changed for important reasons, especially when international requirements change.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__3.html",
"confidence": 9
},
"VC118": {
"revision": 2,
"explanation": "AFuG requires amateur stations to meet EMC protection requirements so their operation remains compatible with other equipment.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__7.html",
"confidence": 9
},
"VC119": {
"revision": 2,
"explanation": "AFuG lets amateurs deviate from EMVG immunity requirements for their own station, meaning they choose their own station's immunity level.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__7.html",
"confidence": 9
},
"VC120": {
"revision": 2,
"explanation": "For self-built amateur equipment, AFuG allows the amateur to determine the station's immunity level instead of meeting ordinary EMVG immunity requirements.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__7.html",
"confidence": 9
},
"VC121": {
"revision": 2,
"explanation": "AFuG provides that BNetzA issues a site certificate on request; this is separate from the amateur-station display procedure.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__7.html",
"confidence": 9
},
"VC122": {
"revision": 2,
"explanation": "AFuG and AFuV enforcement powers allow BNetzA to restrict operation or order an amateur station taken out of service after violations.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__11.html",
"confidence": 9
},
"VC123": {
"revision": 1,
"explanation": "Persistent violations can lead to revocation because the admission and call-sign assignment are administrative permissions tied to lawful operation.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__3.html",
"confidence": 9
},
"VC124": {
"revision": 2,
"explanation": "AFuG treats operating without admission/call sign, commercial telecom service, and unauthorised third-party message relay as fineable offences.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__9.html",
"confidence": 9
},
"VC125": {
"revision": 2,
"explanation": "An unlawful station operation can be pursued by BNetzA as an administrative offence with a monetary fine.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__9.html",
"confidence": 9
},
"VD101": {
"revision": 1,
"explanation": "AFuV §1 points to Anlage 1 for the usable frequency ranges and technical operating conditions by class.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__1.html",
"confidence": 10
},
"VD102": {
"revision": 1,
"explanation": "AFuV says receiving amateur transmissions does not require admission to the amateur service; the admission requirement is for participation by transmitting.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__16.html",
"confidence": 10
},
"VD103": {
"revision": 1,
"explanation": "AFuV requires open language; encryption that hides the content is not open language and is therefore prohibited.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__16.html",
"confidence": 10
},
"VD104": {
"revision": 1,
"explanation": "AFuV permits encryption only for control signals of satellites, remote, automatically working or otherwise remotely controlled stations.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__16.html",
"confidence": 10
},
"VD105": {
"revision": 1,
"explanation": "AFuV expressly forbids using international maritime and aeronautical distress, urgency and safety signals in amateur traffic.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__16.html",
"confidence": 10
},
"VD106": {
"revision": 1,
"explanation": "AFuV requires amateur stations to be installed and maintained according to generally recognised technical rules.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__16.html",
"confidence": 10
},
"VD107": {
"revision": 1,
"explanation": "AFuV lets BNetzA demand technical documents and an antenna layout sketch for a transmitting station.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__16.html",
"confidence": 10
},
"VD108": {
"revision": 1,
"explanation": "AFuV §17 lets BNetzA require records to investigate interference causes or clarify frequency-technical questions.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__17.html",
"confidence": 10
},
"VD109": {
"revision": 1,
"explanation": "Log-like written operating records are mandatory only when BNetzA requires them under AFuV §17.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__17.html",
"confidence": 10
},
"VD110": {
"revision": 1,
"explanation": "AFuV requires unwanted emissions to be reduced to the lowest practicable level.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__16.html",
"confidence": 10
},
"VD111": {
"revision": 1,
"explanation": "During adjustment and measurement, AFuV requires effective measures to prevent free radiation of test signals.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__16.html",
"confidence": 10
},
"VD112": {
"revision": 1,
"explanation": "A carrier is normally not a valid transmission by itself, but a short unmodulated carrier can be necessary for tuning.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__16.html",
"confidence": 9
},
"VD113": {
"revision": 1,
"explanation": "AFuV requires name or address changes to be reported to BNetzA without undue delay.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__9.html",
"confidence": 10
},
"VD114": {
"revision": 1,
"explanation": "AFuV §15 defines the call-sign list content: name, call sign and address unless publication of the address is opposed.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__15.html",
"confidence": 10
},
"VD115": {
"revision": 1,
"explanation": "No BNetzA special permission is needed merely because the amateur station is operated in a watercraft or aircraft; other operator/vehicle permissions still matter.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"VD116": {
"revision": 1,
"explanation": "AFuV §16 allows BNetzA to grant temporary exceptions for special experimental and technical-scientific studies.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__16.html",
"confidence": 10
},
"VD117": {
"revision": 1,
"explanation": "AFuV §2 defines a club station as a station used by at least three members of a group under a jointly used call sign.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__2.html",
"confidence": 10
},
"VD118": {
"revision": 1,
"explanation": "AFuV §2 defines a repeater as a remote or automatic amateur station that re-transmits or forwards received or stored content.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__2.html",
"confidence": 10
},
"VD119": {
"revision": 1,
"explanation": "AFuV §2 defines a beacon as an automatic amateur transmitting station that repeatedly emits signals for field-strength observations or reception tests.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__2.html",
"confidence": 10
},
"VD201": {
"revision": 1,
"explanation": "AFuV §10 requires BNetzA to publish a German amateur call-sign plan that defines the call-sign formation rules.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__10.html",
"confidence": 10
},
"VD202": {
"revision": 1,
"explanation": "AFuV §10 lists person-bound call signs and further call signs for training, remote/automatic stations and club stations.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__10.html",
"confidence": 10
},
"VD203": {
"revision": 1,
"explanation": "The German call-sign plan uses a two-letter German prefix, one digit and usually a two- or three-letter suffix for person-bound call signs.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__10.html",
"confidence": 9
},
"VD204": {
"revision": 1,
"explanation": "The call-sign plan permits special-event suffixes up to seven characters, including digits, provided the suffix ends with a letter.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"VD205": {
"revision": 1,
"explanation": "AFuV §11 requires the call sign at the beginning and end of each contact and at least every ten minutes during traffic.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__11.html",
"confidence": 10
},
"VD206": {
"revision": 1,
"explanation": "BNetzA's call-sign-use rule points to the international spelling alphabet in RR Appendix 14 for identifying call signs.",
"source": "BNetzA Verfügung 13/2005; ITU RR Appendix 14",
"confidence": 8
},
"VD207": {
"revision": 1,
"explanation": "The amateur call sign is the on-air identifier; it tells listeners which amateur station is transmitting.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__11.html",
"confidence": 10
},
"VD208": {
"revision": 1,
"explanation": "AFuV §10 says there is no entitlement to a specific call sign.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__10.html",
"confidence": 10
},
"VD301": {
"revision": 1,
"explanation": "AFuV §12 defines training operation as practical preparation for the amateur-radio exam.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__12.html",
"confidence": 10
},
"VD302": {
"revision": 1,
"explanation": "AFuV §12 permits training operation only for admitted class A or E amateurs.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__12.html",
"confidence": 10
},
"VD303": {
"revision": 1,
"explanation": "AFuV §12 allows non-licensed trainees to participate only under direct instruction and supervision by an authorised class A or E amateur.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__12.html",
"confidence": 10
},
"VD304": {
"revision": 1,
"explanation": "AFuV §12 limits training operation to the operating privileges of the instructor.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__12.html",
"confidence": 10
},
"VD305": {
"revision": 1,
"explanation": "AFuV §12 requires the instructor to provide BNetzA information about the type and extent of training operation on request.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__12.html",
"confidence": 10
},
"VD306": {
"revision": 1,
"explanation": "AFuV §12 and §11 put the training suffix on the trainee's use of the instructor or club call sign.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__12.html",
"confidence": 10
},
"VD401": {
"revision": 1,
"explanation": "AFuV §14 requires the group's leader to name the responsible radio amateur for a club-station call-sign assignment.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__14.html",
"confidence": 10
},
"VD402": {
"revision": 1,
"explanation": "AFuV §14 allows a club-station call sign only to a radio amateur already admitted to participate in the amateur service.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__14.html",
"confidence": 10
},
"VD403": {
"revision": 1,
"explanation": "AFuG §3 allows further call signs, including club-station call signs, only after the amateur has an admission and the additional assignment.",
"source": "https://www.gesetze-im-internet.de/afug_1997/__3.html",
"confidence": 10
},
"VD404": {
"revision": 1,
"explanation": "Only admitted radio amateurs may transmit using a club-station call sign; the club call does not authorise unlicensed operation.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__14.html",
"confidence": 10
},
"VD405": {
"revision": 1,
"explanation": "AFuV permits admitted radio amateurs to operate at a club station even if they are not members of the group.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__14.html",
"confidence": 10
},
"VD406": {
"revision": 1,
"explanation": "When operator class and club-station class differ, the lower privilege set controls frequency and power limits.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__14.html",
"confidence": 10
},
"VD407": {
"revision": 2,
"explanation": "AFuV Anlage 1 lists 7.000-7.200 MHz only in the class A column. A class A club-station call sign does not expand the operator's own licence privileges, so only class A operators may use 40 m there.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD408": {
"revision": 1,
"explanation": "AFuV does not require reporting short-term location changes of a club station, unlike permanent relevant assignment data changes.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__14.html",
"confidence": 9
},
"VD501": {
"revision": 1,
"explanation": "AFuV §13 requires a separate call-sign assignment for remote-controlled or automatically working stations such as repeaters and beacons.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__13.html",
"confidence": 10
},
"VD502": {
"revision": 1,
"explanation": "A repeater may be operated only under its own assigned call sign and the site and operating conditions stated in that assignment.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__13.html",
"confidence": 10
},
"VD503": {
"revision": 1,
"explanation": "AFuV Anlage 1 limits repeater stations above 30 MHz to 50 W ERP.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD504": {
"revision": 1,
"explanation": "The responsible operator may exclude a user when that is necessary to keep the repeater operating without interference.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__13.html",
"confidence": 9
},
"VD601": {
"revision": 1,
"explanation": "AFuV §2 defines remote operation as unoccupied, remotely controlled operation of a fixed amateur station under continuous indirect control.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__2.html",
"confidence": 10
},
"VD602": {
"revision": 1,
"explanation": "AFuV §13a links remote operation to a BNetzA notification by the remote-station operator.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__13a.html",
"confidence": 10
},
"VD603": {
"revision": 1,
"explanation": "AFuV §13a restricts remote operation to holders of class A privileges.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__13a.html",
"confidence": 10
},
"VD604": {
"revision": 1,
"explanation": "AFuV §13a allows class A club stations to be used for remote operation.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__13a.html",
"confidence": 10
},
"VD605": {
"revision": 1,
"explanation": "Remote operation must remain under the operator's continuous indirect control, so the operator must be able to maintain operational safety.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__2.html",
"confidence": 10
},
"VD606": {
"revision": 1,
"explanation": "The remote-station operator must prevent unauthorised or abusive access, so only specifically authorised amateurs may use it.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__13a.html",
"confidence": 10
},
"VD607": {
"revision": 1,
"explanation": "AFuV §13a permits transmission through a remote station only by authorised amateurs with class A admission.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__13a.html",
"confidence": 10
},
"VD608": {
"revision": 1,
"explanation": "BNetzA needs the operator's contact details so it can reach the responsible person quickly in case of radio interference.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__13a.html",
"confidence": 10
},
"VD609": {
"revision": 1,
"explanation": "For a remotely operated club station, AFuV §13a limits access to members of the operating group.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/__13a.html",
"confidence": 10
},
"VD701": {
"revision": 1,
"explanation": "International RR allocations are not self-executing in Germany; AFuV Anlage 1 and BNetzA notices implement the usable national amateur ranges.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD702": {
"revision": 1,
"explanation": "AFuV Anlage 1 is the national table for German amateur frequency ranges and detailed usage conditions.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD703": {
"revision": 1,
"explanation": "CB radio is outside the amateur frequency allocations, so an amateur station is not authorised to transmit there.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD704": {
"revision": 1,
"explanation": "A primary service can claim protection from secondary services, so secondary stations must not interfere with it.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD705": {
"revision": 1,
"explanation": "A secondary service may neither cause harmful interference to primary services nor claim protection from them.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD706": {
"revision": 1,
"explanation": "AFuV Anlage 1 lists 7000-7200 kHz with primary status for the amateur service.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD707": {
"revision": 1,
"explanation": "A coastal station on its fixed assigned frequency cannot simply move; even in a shared primary band the amateur station must stop using that frequency unless a real emergency exists.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 9
},
"VD708": {
"revision": 1,
"explanation": "The 433.05-434.79 MHz ISM designation means non-communication industrial, scientific, medical, domestic or similar applications also use that range.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD709": {
"revision": 1,
"explanation": "This is a direct AFuV Anlage 1 table value: the German amateur allocation is 1810 to 2000 kHz.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD710": {
"revision": 1,
"explanation": "This is a direct AFuV Anlage 1 table value: the German amateur allocation is 3.5 to 3.8 MHz.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD711": {
"revision": 1,
"explanation": "This is a direct AFuV Anlage 1 table value: the German amateur allocation is 7 to 7.2 MHz.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD712": {
"revision": 1,
"explanation": "This is a direct AFuV Anlage 1 table value: the German amateur allocation is 10.1 to 10.15 MHz.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD713": {
"revision": 1,
"explanation": "This is a direct AFuV Anlage 1 table value: the German amateur allocation is 14 to 14.35 MHz.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD714": {
"revision": 1,
"explanation": "This is a direct AFuV Anlage 1 table value: the German amateur allocation is 18.068 to 18.168 MHz.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD715": {
"revision": 1,
"explanation": "This is a direct AFuV Anlage 1 table value: the German amateur allocation is 21 to 21.45 MHz.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD716": {
"revision": 1,
"explanation": "This is a direct AFuV Anlage 1 table value: the German amateur allocation is 24.89 to 24.99 MHz.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD717": {
"revision": 1,
"explanation": "This is a direct AFuV Anlage 1 table value: the German amateur allocation is 28 to 29.7 MHz.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD718": {
"revision": 1,
"explanation": "This is a direct AFuV Anlage 1 table value: the German amateur allocation is 50.0 to 52.0 MHz.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD719": {
"revision": 1,
"explanation": "This is a direct AFuV Anlage 1 table value: the German amateur allocation is 144 to 146 MHz.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD720": {
"revision": 1,
"explanation": "This is a direct AFuV Anlage 1 table value: the German amateur allocation is 430 to 440 MHz.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD721": {
"revision": 1,
"explanation": "This is a direct AFuV Anlage 1 table value: the German amateur allocation is 1240 to 1300 MHz.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD722": {
"revision": 1,
"explanation": "This is a direct AFuV Anlage 1 table value: the German amateur allocation is 2320 to 2450 MHz.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD723": {
"revision": 1,
"explanation": "AFuV Anlage 1 gives class N only the 10 m, 2 m and 70 cm ranges: 28-29.7 MHz, 144-146 MHz and 430-440 MHz.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD724": {
"revision": 1,
"explanation": "For class N on 2 m and 70 cm, AFuV Anlage 1 uses an EIRP cap of 10 W rather than a transmitter-output cap.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD725": {
"revision": 1,
"explanation": "EIRP is transmitter power times antenna gain relative to isotropic: $5 W \\cdot 2.5 = 12.5 W$, which exceeds the 10 W class N limit.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD726": {
"revision": 1,
"explanation": "EIRP is transmitter power times antenna gain relative to isotropic: $5 W \\cdot 1.8 = 9 W$, which stays below the 10 W class N limit.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD727": {
"revision": 1,
"explanation": "AFuV Anlage 1 permits class E operation from 1810 to 1850 kHz with a maximum of 100 W PEP.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD728": {
"revision": 1,
"explanation": "AFuV Anlage 1 lists 750 W PEP for class A in the 3.5-3.8 MHz band.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD729": {
"revision": 1,
"explanation": "AFuV Anlage 1 gives 3.5-3.8 MHz limits of 750 W PEP for class A and 100 W PEP for class E.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD730": {
"revision": 1,
"explanation": "AFuV Anlage 1 limits class A in 10.1-10.15 MHz to 150 W PEP.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD731": {
"revision": 1,
"explanation": "AFuV Anlage 1 lists 750 W PEP for class A on both 14.000-14.350 MHz and 18.068-18.168 MHz.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD732": {
"revision": 1,
"explanation": "AFuV Anlage 1 lists 750 W PEP for class A on both 21.000-21.450 MHz and 24.890-24.990 MHz.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD733": {
"revision": 1,
"explanation": "AFuV Anlage 1 gives 21 MHz and 28 MHz limits of 750 W PEP for class A and 100 W PEP for class E.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD734": {
"revision": 1,
"explanation": "AFuV Anlage 1 gives 144-146 MHz and 430-440 MHz limits of 750 W PEP for class A and 75 W PEP for class E.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD735": {
"revision": 1,
"explanation": "AFuV Anlage 1 allows class A up to 750 W PEP at 1240-1300 MHz but adds a special 5 W EIRP cap in 1247-1263 MHz.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD736": {
"revision": 1,
"explanation": "For class A between 1300 MHz and 250 GHz, AFuV Anlage 1 lists a maximum transmitter output of 75 W PEP.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD737": {
"revision": 1,
"explanation": "For class E between 1300 MHz and 250 GHz, AFuV Anlage 1 lists a maximum transmitter output of 5 W PEP.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD738": {
"revision": 1,
"explanation": "AFuV Anlage 1 sets the narrow 800 Hz occupied-bandwidth limit for 135.7-137.8 kHz, 472-479 kHz and 10.100-10.150 MHz.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD739": {
"revision": 1,
"explanation": "AFuV Anlage 1 gives 3.5-3.8 MHz a maximum occupied bandwidth of 2.7 kHz.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD740": {
"revision": 1,
"explanation": "AFuV Anlage 1 gives 28.000-29.000 MHz a maximum occupied bandwidth of 7 kHz.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD741": {
"revision": 1,
"explanation": "AFuV Anlage 1 gives 144-146 MHz a maximum occupied bandwidth of 40 kHz.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD742": {
"revision": 1,
"explanation": "AFuV Anlage 1 gives 430-440 MHz a 2 MHz occupied-bandwidth limit, with 7 MHz allowed for AM television transmissions.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VD743": {
"revision": 1,
"explanation": "AFuV Anlage 1 caps class N in the 10 m band at 10 W ERP.",
"source": "https://www.gesetze-im-internet.de/afuv_2005/anlage_1.html",
"confidence": 10
},
"VE101": {
"revision": 1,
"explanation": "The TKG is a general telecommunications law; amateur radio has its own law, but frequency-use and enforcement rules from the TKG can still apply.",
"source": "https://www.gesetze-im-internet.de/tkg_2021/BJNR185810021.html",
"confidence": 9
},
"VE102": {
"revision": 1,
"explanation": "TKG §91 states the general rule that every frequency use needs a prior frequency assignment unless the law provides otherwise.",
"source": "https://www.gesetze-im-internet.de/tkg_2021/BJNR185810021.html",
"confidence": 10
},
"VE103": {
"revision": 1,
"explanation": "Using frequencies without the required frequency assignment is a TKG administrative offence.",
"source": "https://www.gesetze-im-internet.de/tkg_2021/BJNR185810021.html",
"confidence": 10
},
"VE201": {
"revision": 1,
"explanation": "Unauthorised listening to the non-publicly spoken word is a criminal offence under StGB §201, independent of holding an amateur licence.",
"source": "https://www.gesetze-im-internet.de/stgb/__201.html",
"confidence": 10
},
"VE202": {
"revision": 1,
"explanation": "TDDDG protects communications not intended for the recipient; receiving, using or passing on such messages violates that confidentiality duty.",
"source": "https://www.gesetze-im-internet.de/ttdsg/__5.html",
"confidence": 10
},
"VE203": {
"revision": 1,
"explanation": "TDDDG §5 bars disclosing both the content and the fact of receiving non-public/non-general messages, except where emergency and disaster rules justify it.",
"source": "https://www.gesetze-im-internet.de/ttdsg/__5.html",
"confidence": 10
},
"VE204": {
"revision": 1,
"explanation": "TDDDG prohibits disguised transmitting devices suited to unnoticed eavesdropping on non-public speech, including possession and manufacture.",
"source": "https://www.gesetze-im-internet.de/ttdsg/__5.html",
"confidence": 10
},
"VE301": {
"revision": 1,
"explanation": "Before escalating an EMC dispute, reducing power is a practical interim measure that may remove the interference and preserve neighbourly peace.",
"source": "https://www.gesetze-im-internet.de/emvg_2016/BJNR287910016.html",
"confidence": 8
},
"VE302": {
"revision": 1,
"explanation": "If local remedies fail, BNetzA is the competent authority to investigate radio-interference causes.",
"source": "https://www.gesetze-im-internet.de/emvg_2016/BJNR287910016.html",
"confidence": 9
},
"VE303": {
"revision": 1,
"explanation": "When both installations are compliant but incompatibility remains, EMVG gives BNetzA authority to arrange remedial measures with the parties.",
"source": "https://www.gesetze-im-internet.de/emvg_2016/BJNR287910016.html",
"confidence": 9
},
"VE304": {
"revision": 1,
"explanation": "EMVG lets BNetzA arrange remedial measures in cooperation with affected parties when compliant equipment still causes a local EMC problem.",
"source": "https://www.gesetze-im-internet.de/emvg_2016/BJNR287910016.html",
"confidence": 9
},
"VE305": {
"revision": 1,
"explanation": "If the amateur field strength at the affected receiver is below the relevant immunity reference level, the amateur station is not the non-compliant part and may continue operation.",
"source": "https://www.gesetze-im-internet.de/emvg_2016/BJNR287910016.html",
"confidence": 8
},
"VE306": {
"revision": 1,
"explanation": "If the field strength at the cable system stays below the recommended immunity level, the amateur transmission is within the assumed compatibility boundary.",
"source": "https://www.gesetze-im-internet.de/emvg_2016/BJNR287910016.html",
"confidence": 8
},
"VE307": {
"revision": 1,
"explanation": "If all bands are disturbed, the likely source is local household electronics, so checking local supplies, lamps, computers and displays is the fastest first isolation step.",
"source": "https://www.gesetze-im-internet.de/emvg_2016/BJNR287910016.html",
"confidence": 7
},
"VE308": {
"revision": 1,
"explanation": "A receiver has no general right to be free of all interference; compliant devices under EMVG or FuAG may still produce disturbance the amateur must tolerate.",
"source": "https://www.gesetze-im-internet.de/emvg_2016/BJNR287910016.html",
"confidence": 9
},
"VE309": {
"revision": 1,
"explanation": "A time/type log and suspected source give BNetzA evidence for pattern matching and field investigation of recurring interference.",
"source": "https://www.gesetze-im-internet.de/emvg_2016/BJNR287910016.html",
"confidence": 8
},
"VE401": {
"revision": 1,
"explanation": "The FuAG implements the market rules for radio equipment, including making radio equipment available, free movement and putting it into service.",
"source": "https://www.gesetze-im-internet.de/fuag/FuAG.pdf",
"confidence": 10
},
"VE402": {
"revision": 1,
"explanation": "Radio equipment made available on the market, including amateur equipment sold commercially, falls under the FuAG.",
"source": "https://www.gesetze-im-internet.de/fuag/FuAG.pdf",
"confidence": 10
},
"VE403": {
"revision": 1,
"explanation": "Serially manufactured amateur radio equipment is market equipment, so it must meet FuAG essential requirements and carry CE marking.",
"source": "https://www.gesetze-im-internet.de/fuag/FuAG.pdf",
"confidence": 10
},
"VE404": {
"revision": 1,
"explanation": "Commercial receivers capable of receiving amateur frequencies are market radio equipment, so FuAG requirements apply.",
"source": "https://www.gesetze-im-internet.de/fuag/FuAG.pdf",
"confidence": 10
},
"VE405": {
"revision": 1,
"explanation": "FuAG excludes amateur radio equipment assembled by radio amateurs for experimental and scientific purposes, so those home-built stations do not need FuAG conformity proof.",
"source": "https://www.gesetze-im-internet.de/fuag/FuAG.pdf",
"confidence": 10
},
"VE501": {
"revision": 1,
"explanation": "EMVU is the environmental side of electromagnetic compatibility: protecting people and the environment from electromagnetic fields.",
"source": "https://www.gesetze-im-internet.de/bemfv/__8.html",
"confidence": 9
},
"VE502": {
"revision": 1,
"explanation": "The fixed amateur-station operator is responsible for demonstrating and maintaining electromagnetic environmental compatibility at the site.",
"source": "https://www.gesetze-im-internet.de/bemfv/__8.html",
"confidence": 10
},
"VE503": {
"revision": 1,
"explanation": "The BEMFV is the regulation that sets the proof procedure for limiting electromagnetic fields from fixed amateur stations.",
"source": "https://www.gesetze-im-internet.de/bemfv/__8.html",
"confidence": 10
},
"VE504": {
"revision": 1,
"explanation": "The BEMFV amateur display procedure lets the amateur independently calculate, document and declare that person-safety limits are met.",
"source": "https://www.gesetze-im-internet.de/bemfv/__8.html",
"confidence": 10
},
"VE505": {
"revision": 1,
"explanation": "Person-protection field limits come from the 26th BImSchV and are applied through the BEMFV proof procedure.",
"source": "https://www.gesetze-im-internet.de/bimschv_26/BJNR196600996.html",
"confidence": 10
},
"VE506": {
"revision": 1,
"explanation": "For fixed amateur stations at 10 W EIRP or more, BEMFV requires the safety distance to be determined by calculation or measurement and documented.",
"source": "https://www.gesetze-im-internet.de/bemfv/__8.html",
"confidence": 10
},
"VE507": {
"revision": 1,
"explanation": "The BEMFV documentation threshold for fixed amateur stations is 10 W EIRP.",
"source": "https://www.gesetze-im-internet.de/bemfv/__8.html",
"confidence": 10
},
"VE508": {
"revision": 1,
"explanation": "Every operator of a fixed amateur station at or above 10 W EIRP must use the BEMFV notification procedure.",
"source": "https://www.gesetze-im-internet.de/bemfv/__8.html",
"confidence": 10
},
"VE509": {
"revision": 1,
"explanation": "The BEMFV notification must be submitted to the responsible BNetzA field office before starting operation.",
"source": "https://www.gesetze-im-internet.de/bemfv/__8.html",
"confidence": 10
},
"VE510": {
"revision": 1,
"explanation": "If the actual station no longer matches the existing notification, the BEMFV procedure must be repeated.",
"source": "https://www.gesetze-im-internet.de/bemfv/__8.html",
"confidence": 10
},
"VE511": {
"revision": 1,
"explanation": "The notification is the amateur's binding declaration that the statutory person-protection limits are met under their own responsibility.",
"source": "https://www.gesetze-im-internet.de/bemfv/__8.html",
"confidence": 10
},
"VE512": {
"revision": 1,
"explanation": "BEMFV requires a clear drawing of the site-related safety distance and the area controlled by the operator with the notification.",
"source": "https://www.gesetze-im-internet.de/bemfv/__8.html",
"confidence": 10
},
"VE513": {
"revision": 1,
"explanation": "From commissioning onward, the operator must keep the supporting compliance documentation ready for BNetzA, including antenna data and site drawings as needed.",
"source": "https://www.gesetze-im-internet.de/bemfv/__8.html",
"confidence": 10
},
"VE514": {
"revision": 1,
"explanation": "After notification, the operator must keep the documentation current and re-notify after material changes that invalidate the original assumptions.",
"source": "https://www.gesetze-im-internet.de/bemfv/__8.html",
"confidence": 10
},
"VE515": {
"revision": 1,
"explanation": "BNetzA accepts several proof methods for amateur stations, including WattWächter, simplified assessment, measurements, and near- or far-field calculations.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"VE516": {
"revision": 1,
"explanation": "The safety distance must cover all emissions the operator intends to make simultaneously, because simultaneous fields add at the exposure location.",
"source": "https://www.gesetze-im-internet.de/bemfv/__8.html",
"confidence": 10
},
"VE517": {
"revision": 1,
"explanation": "Overlapping safety distances require joint assessment when the antennas can transmit at the same time, because exposure is combined.",
"source": "https://www.gesetze-im-internet.de/bemfv/__8.html",
"confidence": 10
},
"VE518": {
"revision": 1,
"explanation": "If other certificate-requiring fixed radio systems are already at the site and total site EIRP reaches 10 W, BEMFV requires a site certificate.",
"source": "https://www.gesetze-im-internet.de/bemfv/__8.html",
"confidence": 10
},
"VE519": {
"revision": 1,
"explanation": "For a fixed amateur station, BEMFV requires a site certificate only when the intended site already has fixed radio systems subject to the site-certificate procedure.",
"source": "https://www.gesetze-im-internet.de/bemfv/__8.html",
"confidence": 10
},
"VE601": {
"revision": 1,
"explanation": "Electrical safety for home-built equipment follows generally recognised engineering practice, which is why VDE rules are the relevant benchmark.",
"source": "VDE 0855-300 and DIN EN 62305/VDE 0185-305",
"confidence": 7
},
"VE602": {
"revision": 1,
"explanation": "Outdoor antenna structures are building works, so the applicable construction law is the law of the German federal state where they are erected.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"VE603": {
"revision": 1,
"explanation": "Recognised lightning-protection rules for antenna installations are published as VDE standards.",
"source": "VDE 0855-300 and DIN EN 62305/VDE 0185-305",
"confidence": 7
},
"VE604": {
"revision": 1,
"explanation": "VDE 0855-300 applies to equipotential bonding and earthing of amateur transmitting installations; the VDE 0185-305 lightning-protection series applies when the building has a lightning-protection system.",
"source": "VDE 0855-300 and DIN EN 62305/VDE 0185-305",
"confidence": 7
},
"VE701": {
"revision": 1,
"explanation": "Licensed amateurs owe annual frequency-protection contributions under TKG and EMVG cost-recovery rules.",
"source": "Frequenzschutzbeitragsverordnung (FSBeitrV)",
"confidence": 8
},
"VE702": {
"revision": 1,
"explanation": "The annual frequency-protection contribution is tied to having an amateur admission, regardless of how much the station is used.",
"source": "Frequenzschutzbeitragsverordnung (FSBeitrV)",
"confidence": 8
},
"VE703": {
"revision": 1,
"explanation": "The BNetzA fee regulation charges for individually attributable acts such as admission to the amateur service and assignment of a person-bound call sign.",
"source": "Besondere Gebührenverordnung BNetzA (BNetzABGebV)",
"confidence": 8
},
"VE704": {
"revision": 1,
"explanation": "Unpaid public fees and contributions can be enforced administratively under the Verwaltungs-Vollstreckungsgesetz.",
"source": "Verwaltungs-Vollstreckungsgesetz (VwVG)",
"confidence": 8
},
"VE705": {
"revision": 1,
"explanation": "Aircraft operation requires the consent of the pilot in command because that person is responsible for the aircraft and onboard radio use.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"VE706": {
"revision": 1,
"explanation": "On a ship in international waters, amateur operation is possible only with the master's consent because the master controls shipboard operations.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
},
"VE707": {
"revision": 1,
"explanation": "Damage caused by an antenna installation is a civil-liability issue for the owner or operator who controls that installation.",
"source": "https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Amateurfunk/Fragenkatalog/BetriebVorschriftFragKlAuEId7830pdf.pdf?__blob=publicationFile",
"confidence": 8
}
}
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