🧮 Formulas to memorize
| Formula | What it gives you | Example | Why? |
|---|---|---|---|
| E = I × R | Ohm's law: volts = amps × ohms | 2 A through 50 Ω → 100 V | Why it matters → |
| P = E × I | Power in watts | 13.8 V × 10 A → 138 W | Why it matters → |
| P = E² / R | Power when you know volts and resistance | 100 V into 50 Ω → 200 W | Why it matters → |
| λ (m) = 300 / f (MHz) | Wavelength | 146 MHz → about 2 m | Why it matters → |
| 468 / f (MHz) | Half-wave dipole length in feet | 14.2 MHz → about 33 ft | Why it matters → |
| 234 / f (MHz) | Quarter-wave vertical in feet | 146 MHz → about 19 in | Why it matters → |
| XL = 2πfL | Inductive reactance (rises with frequency) | General | Why it matters → |
| XC = 1 / (2πfC) | Capacitive reactance (falls with frequency) | General | Why it matters → |
| f = 1 / (2π√LC) | Resonant frequency, where XL = XC | General | Why it matters → |
| RMS = peak × 0.707 | Peak = RMS × 1.414; peak-to-peak = 2 × peak | 120 V RMS → 170 V peak | Why it matters → |
| PEP = (Vp-p ÷ 2 × 0.707)² / R | Peak envelope power from a scope reading | 200 V p-p into 50 Ω → 100 W | Why it matters → |
| Vs / Vp = Ns / Np | Transformer voltage follows the turns ratio; impedance ratio is the turns ratio squared | General | Why it matters → |
| SWR = Zbig / Zsmall | SWR from a mismatch (always ≥ 1) | 200 Ω load on 50 Ω line → 4:1 | Why it matters → |
| dBi = dBd + 2.15 | Gain over isotropic vs. over a dipole | General | Why it matters → |
🧠 Why the formulas matter: plain-English explainers for learning
Each formula above links here. Every explainer says what the formula really means, where you'd actually use it with a radio in your hand, and how the exam tends to ask about it. A few have a little calculator so you can poke at the numbers.
Ohm's law
What it means. Think of water in a hose. Voltage (E) is the pressure, current (I) is how much water flows, and resistance (R) is how narrow the hose is. Push harder or widen the hose and more flows. Know any two and the third falls out.
On the air. It's why a long, thin power cable to a mobile radio is a problem: at 20 amps, even a tenth of an ohm in the wire drops 2 volts, and the radio sags, distorts or shuts off. It also tells you what resistor an LED needs and why a fuse is rated in amps.
On the exam. Straight arithmetic: "What is the current through a 10 Ω resistor with 120 V across it?" (12 A). Cover the letter you want in the E-over-I×R triangle and the other two show the answer.
Power
What it means. Watts are how hard the circuit is working: pressure times flow. The second version is the same idea when you know voltage and resistance instead of current.
On the air. This is how you size a power supply. A "100-watt" HF radio is only around 35–40% efficient, so it pulls close to 20 amps from a 13.8 V supply while transmitting: buy a supply rated 25–30 A, not 10. The E²/R version is how a voltmeter across a 50 Ω dummy load tells you real output power.
On the exam. "How much power does a 13.8 V radio drawing 10 A use?" (138 W), and the dummy-load style: "What power is 100 V RMS into 50 Ω?" (200 W).
Wavelength
What it means. Radio waves travel at the speed of light, 300 million meters a second. Divide that by how many waves pass each second (the frequency) and you get the length of one wave. With frequency in megahertz the millions cancel, leaving 300 / f.
On the air. The band names are wavelengths: 146 MHz is "2 meters," 7 MHz is "40 meters." And antennas scale with the wave, which is why a 2 m antenna fits on a handheld while a 160 m antenna needs a big backyard.
On the exam. "Which band is 446 MHz in?" (70 cm), or "What is the wavelength of a 50 MHz signal?" (6 m). Higher frequency always means shorter wavelength.
Half-wave dipole length
What it means. Half a wavelength in feet is 492 / f. A real wire antenna works best about 5% shorter than that, because of how current behaves at the wire's ends, so the rule of thumb is 468 / f for the whole dipole, half on each side of the center feed.
On the air. It's the first antenna most people build for HF. Cut it a little long, check the SWR, and trim both ends a bit at a time until the lowest SWR lands where you want to operate. Too long tunes it low in frequency; too short tunes it high.
On the exam. "About how long is a half-wave dipole for 14.250 MHz?" (about 33 feet).
Read more: dipole antenna ↗ ↑ back to the formulasQuarter-wave vertical
What it means. Half of the dipole number. A vertical is half a dipole standing up: the ground, a car roof or a set of radial wires acts as a mirror and supplies the missing half.
On the air. The classic 2 m mag-mount on a car roof is about 19 inches, and the roof is its other half. That's also why a handheld's antenna works better when you hold the radio, since your hand and body become part of the ground side.
On the exam. "How long is a quarter-wave vertical for 146 MHz?" (about 19 inches).
Read more: monopole antenna ↗ ↑ back to the formulasReactance
What it means. Coils and capacitors push back against AC, and how hard depends on frequency. A coil (inductor) resists more as frequency rises; a capacitor resists less. Unlike a resistor, they store energy rather than turning it into heat.
On the air. This is how filters work. A ferrite choke on a cable is an inductor that blocks RF but lets audio and DC through, which cures hum and RF in your microphone. A loading coil on a short mobile whip adds inductance so the stubby antenna acts like a full-size one, and an antenna tuner is just adjustable coils and capacitors.
On the exam. General asks which way reactance moves with frequency, and occasionally a calculation. Remember: inductors like low frequencies, capacitors like high ones.
Read more: reactance ↗ ↑ back to the formulasResonance
What it means. Put a coil and a capacitor together and at one frequency their reactances are exactly equal and opposite, so they cancel. The circuit "rings" there like a bell, passing or blocking that one frequency far more than any other.
On the air. Resonance is how a receiver picks one station out of thousands, how the traps on a multiband trap dipole switch the antenna's length per band, and what "a resonant antenna" means: one whose own L and C cancel at the frequency you're using.
On the exam. "What happens at resonance?" (XL = XC), and sometimes a resonant-frequency calculation. More L or more C means a lower resonant frequency.
Read more: LC circuits ↗ ↑ back to the formulasRMS, peak and peak-to-peak
What it means. AC voltage swings up and down, so "how many volts" needs a definition. Peak is the top of the swing; peak-to-peak is top to bottom; RMS is the DC voltage that would heat a resistor the same amount. Your wall outlet's 120 V is RMS; it actually peaks near 170 V.
On the air. Parts have to survive the peaks, not the average, so capacitors in tuners and amplifiers are rated well above the RMS voltage. An oscilloscope shows peak-to-peak, so you convert to RMS before working out power.
On the exam. "What is the peak voltage of 120 V RMS?" (about 170 V) and "peak-to-peak?" (about 339 V).
Read more: root mean square ↗ ↑ back to the formulasPeak envelope power
What it means. A voice signal on SSB has no steady carrier; it rises and falls as you talk. PEP is the power at the loudest instant, the top of the signal's envelope. The formula turns a scope reading into watts: halve peak-to-peak to get peak, multiply by 0.707 for RMS, then square and divide by the load.
On the air. The legal power limits (1,500 W, or 200 W on 30 m and for Technicians on HF) are measured as PEP. It's also why a speech processor makes you sound louder without raising PEP: it lifts the average, not the peak.
On the exam. "200 V peak-to-peak across 50 Ω, what is the PEP?" (100 W). For a steady carrier, PEP equals average power.
Read more: peak envelope power ↗ ↑ back to the formulasTransformers
What it means. Two coils sharing a core. Voltage changes by the ratio of their turns: fewer turns on the secondary steps the voltage down. Impedance changes by the turns ratio squared.
On the air. A power supply's transformer steps 120 V down toward 13.8 V. The same idea matches antennas: an end-fed half-wave has a feed impedance in the thousands of ohms, and a 49:1 transformer (7:1 turns, since 7² = 49) brings it close to the 50 Ω the radio wants. Baluns and ununs are transformers too.
On the exam. "120 V on a 2,250-turn primary, 500-turn secondary: what comes out?" (about 26.7 V), and turns-ratio-for-impedance questions.
Read more: transformers ↗ ↑ back to the formulasStanding wave ratio
What it means. When the antenna's impedance doesn't match the 50 Ω coax, some power bounces back down the line toward the radio. SWR measures how bad the mismatch is: 1:1 is perfect, and a quick estimate is simply the bigger impedance over the smaller one.
On the air. It's the number you watch while trimming an antenna. Modern radios cut their power to protect themselves when SWR climbs much past 2:1, and reflected power also means more loss in the coax. At 2:1 only about 11% is reflected, which is why 2:1 is the usual "good enough" line.
On the exam. "What SWR does a 200 Ω load on 50 Ω line give?" (4:1), "25 Ω?" (2:1), and what high SWR tells you about the antenna system.
Antenna gain: dBi and dBd
What it means. Antennas don't make power; they aim it. Gain says how much stronger the antenna's best direction is than a reference. dBi compares against an imaginary antenna that radiates equally in every direction; dBd compares against a real dipole, which already has 2.15 dB of gain over that.
On the air. Ads love dBi because the number is bigger. A "5 dBi" antenna and a "2.85 dBd" antenna are the same. Convert before you compare, or you'll pay for 2 dB that doesn't exist.
On the exam. Converting between the two, and what gain means for a Yagi's pattern.
Read more: antenna gain ↗ ↑ back to the formulasDecibels
What it means. Decibels compare two powers on a log scale, which matches how our ears and radios actually perceive strength. Doubling the power is only +3 dB; ten times the power is +10 dB.
On the air. This is the most useful idea on the sheet. Going from 100 W to 400 W with an amplifier is just 6 dB, about one S-unit on the other station's meter. A better antenna that adds 6 dB does the same thing for both transmitting and receiving, which is why hams say "spend on the antenna first."
On the exam. "A 3 dB loss leaves what fraction of the power?" (half), "How many dB is a power increase from 5 W to 50 W?" (10 dB), and S-units.
📜 T1 · FCC rules
| Rule | The answer they want |
|---|---|
| Which rules govern hams | FCC Part 97. The FCC licenses; the ITU sets international allocations. |
| License term | 10 years · renew within 90 days before it expires · 2-year grace to renew after, but no transmitting in the grace period |
| When can I transmit? | As soon as the call sign shows up in the FCC's ULS database (the FCC emails a link to the license) |
| Station ID | Your call sign every 10 minutes during a contact and at the end, in English or Morse |
| Control operator | Any licensed ham the station licensee designates; privileges are the control operator's. Licensee and control operator are both responsible. |
| Maximum power | 1,500 W PEP · Techs on HF CW segments: 200 W PEP · always the minimum power necessary |
| Not allowed | Music, obscene or indecent language, codes meant to hide meaning, broadcasting to the public, and getting paid (business on behalf of an employer) |
| Exceptions | Encryption is allowed for controlling a space station or a model craft; retransmitting NASA/space-station audio is allowed |
| Third-party traffic | Letting an unlicensed person talk: OK with the control operator present, and only to countries with a third-party agreement |
| Emergencies | When life or property is in immediate danger, use any means necessary to get help |
| Secondary allocations | Hams must not interfere with, and must accept interference from, the primary users (e.g. parts of 70 cm) |
| Band | Technician privileges |
|---|---|
| 80 / 40 / 15 m | 3.525–3.600 · 7.025–7.125 · 21.025–21.200 MHz, CW only, 200 W |
| 10 m | 28.000–28.300 CW, RTTY and data (FT8 lives at 28.074) · 28.300–28.500 CW and SSB voice · beacons sit at 28.200–28.300 |
| 6 m | 50–54 MHz (50.0–50.1 CW only) |
| 2 m | 144–148 MHz (144.0–144.1 CW only) |
| 1.25 m | 222–225 MHz |
| 70 cm | 420–450 MHz |
| 33 / 23 cm | 902–928 MHz · 1240–1300 MHz |
🎙️ T2 · Operating procedures
| Topic | Remember |
|---|---|
| Repeater offsets | 2 m ±600 kHz · 1.25 m −1.6 MHz · 70 cm ±5 MHz |
| Can't open a repeater? | Usually a missing or wrong CTCSS (PL) tone; also check the offset |
| National FM simplex calling | 146.520 MHz (70 cm: 446.000) |
| Calling on a repeater | Just say your call sign; "CQ" is for open calls on HF/simplex |
| Band plans | Voluntary agreements (e.g. which part is for FM or weak-signal) beyond what the FCC requires |
| ARES / RACES | ARES: ARRL volunteers serving agencies · RACES: government civil-defense communications |
| Nets | A net control station runs it; emergency traffic always goes first |
| Messages | Pass them exactly as received; the "check" is the word count of the text |
🌐 T3 · Radio waves and propagation
Mostly line of sight; the radio horizon is a bit farther than the visual one because the atmosphere bends signals. UHF gets into buildings better (shorter wavelength).
Polarization: vertical for FM and repeaters, horizontal for SSB/CW weak-signal work. Mismatched polarization costs a lot of signal.
The D layer absorbs lower HF in daytime. The F layer (F2) reflects signals for long-distance contacts. Higher sunspots support higher frequencies.
The 2026 pool says signals "reflect" off the ionosphere.
Sporadic E: 6 m and 10 m openings, often in summer. Meteor scatter: best on 6 m. Tropospheric ducting: VHF/UHF hundreds of miles along weather fronts.
Aurora: signals sound raspy. Knife-edge diffraction: signals bend around a sharp ridge or building edge.
Picket fencing: rapid fluttering of a mobile FM signal from multipath. Moving the antenna a few feet can fix multipath dropouts.
Frequency × wavelength = speed of light: higher frequency, shorter wavelength.
🔌 T5–T6 · Electrical principles and components
| Quantity | Unit | Notes |
|---|---|---|
| Voltage (EMF) | volt | Measured in parallel with a voltmeter |
| Current | ampere | Measured in series with an ammeter |
| Resistance | ohm | Measure with the circuit powered off |
| Power | watt | Rate of using energy |
| Capacitance | farad | Stores energy in an electric field |
| Inductance | henry | Stores energy in a magnetic field |
| Frequency | hertz | Cycles per second |
Diode: current one way (rectifier) · LED: lights when forward-biased · Transistor: amplifier or switch · Relay: switch worked by an electromagnet · Fuse: opens on overload · Potentiometer: variable resistor (volume) · Transformer: changes AC voltage
Conductors (copper) vs insulators (glass, plastic). A short blows the fuse; an open stops current. A tuned circuit (inductor + capacitor) picks one frequency.
Schematic symbols show up: learn resistor, capacitor, inductor, diode, transistor, battery, ground.
🛠️ T4 / T7 · Station setup and equipment
| Gear | Remember |
|---|---|
| SWR meter | Shows how well the antenna matches the feed line; 1:1 is perfect, under 2:1 is fine |
| Dummy load | A non-radiating 50 Ω resistor for testing without putting a signal on the air |
| Antenna analyzer | Measures SWR and impedance across frequencies without transmitting |
| Multimeter | Voltmeter in parallel, ammeter in series, ohmmeter with the power off |
| VFO | Variable-frequency oscillator: the tuning knob's oscillator |
| Transceiver | Transmitter + receiver in one box; mobile radios wire straight to the battery, with fuses in both leads |
| RF interference | Fix with filters, ferrite chokes and good grounding; check your own station first |
| Overdeviation | FM audio too loud: back off the mic or talk farther from it |
| Distorted signal reports | Low battery, RF feedback, or too much mic gain |
🛰️ T8 · Modes, digital and satellites
| Mode | Bandwidth / use |
|---|---|
| CW | Narrowest, about 150 Hz |
| SSB voice | About 3 kHz; weak-signal VHF and HF. Upper sideband on VHF/UHF and 10 m. |
| FM voice | About 10–15 kHz; repeaters |
| FT8 | Weak-signal digital in 15-second slots; Techs can use it on 10 m and VHF |
| DMR | Digital voice with talkgroups, a color code to reach a repeater, and a code plug file to program the radio |
| D-STAR / Fusion | Other digital voice systems |
| APRS | Position and short messages by packet; 144.390 MHz in the US |
| Winlink | Email over radio, useful in emergencies |
🗼 T9 · Antennas and feed lines
A dipole radiates broadside to its wire. A quarter-wave vertical is omnidirectional. A Yagi beams in one direction for gain. A 5/8-wave vertical has more gain than a 1/4-wave.
The "rubber duck" on a handheld is short and inefficient; an outside antenna helps a lot. To make an antenna resonate lower, make it longer.
Coax is usually 50 Ω. Loss goes up with frequency and with length; air or foam dielectric loses less than solid. Water in the coax is the classic cause of rising loss.
Connectors: PL-259/SO-239 for HF, Type N for UHF and microwaves.
⚠️ T0 · Electrical and RF safety
| Topic | Remember |
|---|---|
| RF exposure | Non-ionizing; it heats body tissue. Exposure limits (MPE) are lowest around 30–300 MHz, where the body absorbs most. |
| What affects exposure | Power, distance, frequency, antenna pattern and duty cycle |
| Station evaluation | Required to confirm you meet the RF exposure rules; move the antenna or cut power to fix |
| Household current | As little as 0.1 A through the body can be fatal; use a GFCI, correctly sized fuses, and never a bigger fuse than specified |
| Lightning | Ground all antenna systems to a common point; disconnect in storms |
| Towers | Wear a harness and hard hat, have a buddy, and never climb with power on the antennas |
📜 G1 · Commission's rules 5 questions
| Band | CW / data | Phone / image |
|---|---|---|
| 160 m | 1.800–2.000 MHz, all modes | |
| 80 m | 3.525–3.600 | 3.800–4.000 |
| 40 m | 7.025–7.125 | 7.175–7.300 |
| 30 m | 10.100–10.150 (200 W PEP max) | No phone |
| 20 m | 14.025–14.150 | 14.225–14.350 |
| 17 m | 18.068–18.110 | 18.110–18.168 |
| 15 m | 21.025–21.200 | 21.275–21.450 |
| 12 m | 24.890–24.930 | 24.930–24.990 |
| 10 m | 28.000–28.300 | 28.300–29.700 |
| Rule | The answer they want |
|---|---|
| Just upgraded, not in the database yet | Add "/AG" after your call when using General privileges |
| CSCE (exam certificate) | Good for 365 days |
| Volunteer Examiners | Three VEs per session; a General can be a VE for Technician exams only |
| Beacons | Max 100 W output |
| Staying inside the band | Your sidebands must stay inside: LSB on 7.178 occupies about 7.175–7.178, so don't go lower. Keep about 3 kHz from any edge. |
| Spurious emissions | Must be kept low enough not to cause interference; you must fix them |
| Automatic control | Repeaters and auxiliary stations can run without an operator present; HF automatic digital stations have their own segments |
🎙️ G2 · Operating procedures 5 questions
| Topic | Remember |
|---|---|
| Which sideband | LSB below 10 MHz (160, 80, 40 m) · USB above (20 m and up) · 60 m is USB even though it's low |
| Before calling CQ | Listen, then ask "Is this frequency in use?" (on CW: QRL?) |
| CW | Zero beat = match the other station's frequency · full break-in (QSK) = hear between your own dots and dashes · QRS = send slower |
| Signal reports | RST: Readability 1–5, Strength 1–9, Tone 1–9 (CW only). "59" is a typical phone report. |
| DX etiquette | A rare station working split listens on a different frequency; call where they say, not on top of them |
| RTTY | 170 Hz shift, 45 baud, usually on LSB settings |
| Digital segments | FT8 and other data cluster near the bottom of each band, e.g. 14.070–14.095 MHz |
| Nets and emergencies | In an emergency, normal privileges can be exceeded to save life or property; nets give emergency traffic priority |
| QRP | 5 W or less |
☀️ G3 · Radio wave propagation 3 questions
Sunspot cycle ≈ 11 years. More sunspots → higher MUF → 10–15 m open up. The solar flux index (10.7 cm radio noise) tracks it; higher is better.
A flare's UV and X-rays arrive in about 8 minutes and can black out HF on the sunlit side. Charged particles from a CME arrive in 20–40 hours and bring geomagnetic storms and aurora.
K index: geomagnetic activity over 3 hours, 0–9. A index: the daily average. Low K and A = good HF conditions.
MUF: highest frequency that comes back to Earth on a path. LUF: lowest usable before absorption wins. Operate just under the MUF.
D layer: daytime absorption of 160–40 m, gone at night. E layer: single hop up to about 1,200 mi. F2 layer: highest, single hop up to about 2,500 mi.
Critical angle: launch any steeper and the signal goes into space.
NVIS: low antenna, high angle, 40/80 m, fills in 0–300 mi around you. Grey line: enhanced along the day/night boundary. Long path: the other way around the planet; the beam heading is 180° off.
Skip zone: too far for ground wave, too close for the first hop.
🎛️ G4 · Amateur radio practices 5 questions
| Control or test | What it does |
|---|---|
| ALC | Automatic level control: keeps the amplifier from being overdriven; too much ALC means splatter |
| Speech processor | Raises average power on SSB, not peak; too much distorts |
| Two-tone test | Two non-harmonic audio tones to check an SSB transmitter's linearity |
| RIT | Receive incremental tuning: shifts only the receiver a little |
| Noise blanker | Cuts impulse noise (ignitions, power lines) |
| Notch filter | Removes a single interfering carrier or tone |
| IF shift | Slides the passband to dodge nearby interference |
| Tube amplifier tuning | Tune for a dip in plate current; watch grid current so you don't overdrive |
| Oscilloscope | Best for looking at a transmitted waveform |
| S-meter | Relative signal strength; each S-unit ≈ 6 dB, so going up one S-unit takes about 4× the power |
| Hum or RF on audio | Ground loops or RF feedback; fix with a single-point ground and ferrite chokes |
| Mobile HF | The antenna is the weak link; wire power straight to the battery |
⚡ G5 · Electrical principles 3 questions
Reactance is opposition to AC from L and C. Inductors resist more as frequency rises; capacitors resist less. Impedance = resistance + reactance; matching it transfers the most power.
At resonance, XL = XC.
RMS is the heating-equivalent DC voltage. PEP is the average power over one RF cycle at the highest peak of the envelope. For an unmodulated carrier, PEP = average.
A transformer's impedance ratio is the square of its turns ratio.
🧩 G6 / G7 · Components and practical circuits 5 questions
| Part or circuit | Remember |
|---|---|
| Electrolytic capacitor | Big capacitance in a small package; polarized |
| Ceramic capacitor | Small, cheap, good at RF |
| Schottky diode | Low forward voltage drop |
| Zener diode | Holds a constant voltage (regulation) |
| MOSFET | Gate is insulated: very high input impedance |
| Ferrite / toroid | Chokes RF on cables; toroids keep the magnetic field inside the core |
| Power supply | Full-wave rectifier output is 120 Hz pulses on 60 Hz mains; a filter capacitor smooths it; a bleeder resistor discharges the caps when off |
| Superheterodyne | A mixer makes sum and difference frequencies to land the signal on a fixed IF |
| Oscillator | An amplifier with positive feedback |
| Amplifier classes | Class A most linear, least efficient · AB for SSB · Class C most efficient but only for CW and FM |
| Logic | AND: all inputs high · OR: any input high · NAND: output low only when all inputs are high · a flip-flop stores one bit |
| DSP | Filtering and demodulation done in software after digitizing the signal |
〰️ G8 · Signals and emissions 3 questions
| Mode | About this wide | Notes |
|---|---|---|
| FT8 | 50 Hz | 15-second transmit periods |
| PSK31 | ~31 Hz | Keyboard chat, very narrow |
| CW | ~150 Hz | |
| RTTY | ~250 Hz | 170 Hz shift |
| SSB | ~3 kHz | One sideband, no carrier: the most efficient voice mode |
| AM | ~6 kHz | Carrier plus both sidebands |
| FM | 10–15 kHz | Only above 29 MHz on HF (the top of 10 m) |
🗼 G9 · Antennas and feed lines 4 questions
Half-wave dipole ≈ 468 / f ft; feed-point impedance about 72 Ω in free space, changing with height. Quarter-wave ground-mounted vertical ≈ 36 Ω; sloping its radials down raises it toward 50 Ω.
A trap dipole works several bands. A loading coil makes a short antenna resonate. An end-fed half-wave has a very high feed impedance and needs a matching transformer.
The reflector is longer than the driven element; directors are shorter. A longer boom with more directors means more gain and a narrower beam.
Front-to-back ratio: forward signal vs. the back. Gain in dBi = dBd + 2.15.
Ladder line (window line) has much less loss than coax, even at high SWR. Coax loss grows with frequency and length. High SWR adds loss in the line as heat.
An antenna tuner at the radio doesn't fix the SWR on the line; it only makes the radio see 50 Ω.
A dipole's pattern is a figure eight, strongest broadside. A low horizontal antenna sends energy straight up (good for NVIS). Raising it lowers the radiation angle for DX.
A log-periodic covers a wide frequency range with fairly flat gain.
⚠️ G0 · Electrical and RF safety 2 questions
| Topic | Remember |
|---|---|
| Duty cycle in exposure math | FM and data ≈ 100% · CW ≈ 40% · SSB voice ≈ 20%: a lower duty cycle allows more power for the same exposure |
| Averaging time | Exposure is averaged over 6 minutes (controlled, i.e. you and your family) or 30 minutes (uncontrolled, i.e. neighbors and the public) |
| Doing the evaluation | Calculate with the FCC's OET Bulletin 65 tables or software, or measure with a calibrated field-strength meter |
| Generators | Run outdoors, away from windows: carbon monoxide |
| Grounding | Bond everything to a single-point ground; put lightning arrestors where cables enter the house |
| Wiring | Three-wire cords with the green ground; GFCI near water; fuses in the hot lead |
📝 What to bring and how to play it
Photo ID · your FRN from the FCC's CORES system · the session fee if any · pencils · a calculator (the team may ask to see its memory cleared)
Check the session listing: some teams want you to register ahead.
No penalty for wrong answers, so answer every question. Skip the math on the first pass and come back. "Always" and "never" answers are usually wrong.
Pass Technician, then ask to sit General right away. After the session, pay the $35 FCC fee within 10 days of the email.