HamCompass — Technician License Cram Guide

🧭 HamCompass

Technician Cram Guide

2026–2030 Pool · High-yield focus · Pass = 26 of 35 correct

Rules &
Licensing

Operating
Procedures

Propagation

Station
Setup

Electrical
Math

Components

Equipment &
Troubleshoot

Modes &
Activities

Antennas

Safety

⚡ Must-Know Formulas (T5)

Ohm's Law

V = I × R

V = Volts I = Amps R = Ohms
Rearrange: I = V/R R = V/I

Power

P = I × E

P = Watts I = Amps E = Volts
Also: P = E²/R or P = I²R

Frequency / Wavelength

λ = 300 / f(MHz)

λ in meters, f in MHz
Dipole ≈ 468 / f(MHz) feet

Decibels (Power)

dB = 10 log(P₂/P₁)

Quick shortcuts:

+3 dB = 2× +6 dB = 4× +10 dB = 10×

🎯 Instant-Answer Flashcards

Station ID — how often?

Every 10 min AND at end of QSO

Station ID language

English (or telegraphy)

License term

10 years

Grace period after expiry

2 years (no transmitting)

2m simplex calling freq

146.520 MHz

2m repeater offset

+600 kHz

70cm repeater offset

+5 MHz

Maximum power (Technician)

1500 W PEP (most bands)

Minimum safe SWR

1:1 is ideal; <2:1 acceptable

Dummy load use

Testing transmitter without antenna

CTCSS (PL tone)

Subaudible tone to access repeater

APRS

Automatic Packet Reporting System (GPS/data)

FT8 mode type

Digital (weak-signal HF)

Morse code (continuous wave)

Part 97

FCC rules for amateur radio

Third-party traffic

Allowed only with certain countries

Rules & Licensing

FCC Part 97, privileges, callsigns, prohibited ops

6 Qs

▼

Three license classes: Technician → General → Amateur Extra
Technician HF privileges (CW/data only, no phone): 80m: 3.525 MHz | 40m: 7.025 MHz | 15m: 21.025–21.200 MHz | 10m: 28.000–28.500 MHz (phone 28.300–28.500)
Full VHF/UHF privileges — 6m, 2m, 1.25m, 70cm, and up (all modes, full power)
License term: 10 years | Grace period: 2 years (no transmitting)
Station ID: Every 10 minutes AND at the end of each contact — both, not either/or
ID language: English (or Morse code)
Control operator must be a licensed amateur; responsible for proper operation
Callsign formats: 1×2 (W1AB), 2×1 (WA1B), 2×2 (WA1AB), 1×3 (W1ABC) — must use assigned callsign
Club station: needs a licensed trustee
Vanity callsigns are available — apply via FCC ULS
PROHIBITED: music, broadcasting, obscenity, unidentified transmissions, encrypted messages (except control codes), false distress signals
Business communications — generally prohibited; exceptions (e.g., emergency, remote control of model craft)
ARES = Amateur Radio Emergency Service (ARRL volunteers) | RACES = Radio Amateur Civil Emergency Service (government-activated)
Emergency comms: can communicate with non-amateur stations when life/property at risk
Frequency coordinator — recommended (not required) for repeater frequency assignments
Third-party traffic — allowed only to/from countries with which USA has agreement; check ARRL list
Foreign visitors: can operate under reciprocal agreements with their home license

Band	Frequency	Tech Phone?	Tech CW/Data?
80m	3.525 MHz	No	Yes
40m	7.025 MHz	No	Yes
15m	21.025–21.200	No	Yes
10m	28.000–28.500	28.300–28.500 ✓	Yes (all)
6m+	50 MHz and up	Yes — full	Yes — full

Common Gotchas

ID is every 10 min AND at end — missing either is wrong on the exam
Technician does NOT have phone (SSB/FM) on 40m or 80m — CW/data only
You can still transmit on 10m phone as a Tech (28.300–28.500 MHz)
ARES is voluntary; RACES is government-activated — exam distinguishes them

Operating Procedures

Repeaters, Q-codes, emergency calling, phonetics

3 Qs

▼

CQ = calling any station (general call)
73 = best regards | 88 = love and kisses
Simplex: transmit and receive on the same frequency
Repeater offset: 2m = +600 kHz; 70cm = +5 MHz (input higher than output)
CTCSS / PL tone = subaudible tone required by many repeaters to open squelch
DTMF = touch-tone tones used to control repeaters/IRLP/EchoLink
IRLP / EchoLink = internet-linked repeater systems
2m emergency/calling frequency: 146.520 MHz
Phonetic alphabet: Alpha, Bravo, Charlie, Delta, Echo, Foxtrot, Golf, Hotel, India, Juliet, Kilo, Lima, Mike, November, Oscar, Papa, Quebec, Romeo, Sierra, Tango, Uniform, Victor, Whiskey, X-ray, Yankee, Zulu
Q-codes: QRM = manmade interference | QRN = static (natural) | QSB = fading | QSY = change frequency | QRZ = who is calling me? | QSL = I acknowledge
Break! Break! — signals emergency interruption of ongoing QSO
Tactical callsign (e.g., "Net Control") — OK, but must still give FCC callsign every 10 min and at end

Mnemonic — Repeater Offset Direction

"Up to get in" — your transmit (input to repeater) is UP from the output frequency you hear. 2m: hear 147.000, transmit 147.600.

Radio Wave Propagation

Ionosphere, VHF/UHF, skip, ducting

3 Qs

▼

VHF/UHF primary mode: line-of-sight — signals travel straight, blocked by terrain
Ionosphere: layers of ionized gas that reflect/absorb radio waves D layer (lowest): absorbs HF during daytime, disappears at night | E layer: reflects some HF, sporadic E | F layer (highest): primary HF reflection, day and night
Skip / skywave: HF signals bounce off F-layer → long-distance contacts (hundreds to thousands of miles)
Skip zone: area between ground-wave range and where sky-wave lands — no signal received there
Sporadic E (Es): patchy E-layer ionization → unexpected long-distance contacts on 6m and occasionally 2m
Tropospheric ducting: temperature inversion bends VHF/UHF signals → extended range beyond line-of-sight
Multipath / picket fencing: signal arrives via multiple paths → rapid flutter on mobile VHF/UHF
Auroral propagation: signals reflect off aurora → distorted, buzzy audio; mostly useful on 2m/6m
Sunspot cycle: 11-year cycle; high sunspots = better HF conditions (more F-layer ionization)
Knife-edge diffraction: VHF/UHF signals can bend slightly around sharp ridges

Common Gotchas

VHF/UHF is line-of-sight — repeaters on hills extend range
The D layer absorbs, it doesn't reflect (that's why 80m/40m don't do skip during daytime)
Sporadic E can happen suddenly — not the same as regular E-layer propagation

Station Setup

Transceivers, meters, grounding, RF safety

2 Qs

▼

SWR meter: goes between transmitter and antenna — measures impedance match
Dummy load: resistive load (no radiation) for testing transmitter without antenna
RF ground vs. safety ground: RF ground reduces interference; safety ground prevents shock
Transceiver: transmitter + receiver in one unit
Microphone placement: speak across (not directly into) mic to reduce popping
VOX: voice-operated transmit — keys radio when you speak
RFI in consumer electronics: add bypass capacitor or ferrite choke at the affected device
Computer-radio interface: audio + PTT line (serial or VOX) between radio and PC for digital modes
Fuse on power cable: as close to the battery/power supply as possible — protects wire from fire

Electrical Principles & Math

Ohm's law, power, units, decibels, AC/DC

4 Qs

▼

Units prefixes: kilo (k) = 1,000 | Mega (M) = 1,000,000 | milli (m) = 1/1,000 | micro (µ) = 1/1,000,000
Ohm's Law triangle: V top; I and R on bottom. Cover what you want: V=IR, I=V/R, R=V/I
Power formulas: P = IE | P = E²/R | P = I²R
Example: 12V battery, 2A draw → P = 12 × 2 = 24 watts
Example: 120V, 100Ω → I = 120/100 = 1.2 A
Decibel quick math: 3 dB = 2× power | −3 dB = half | 10 dB = 10× | 20 dB = 100×
Frequency = 1 / period (Hz = cycles per second)
DC: flows one direction | AC: alternates direction (household = 60 Hz)
Capacitor in AC circuit: passes AC, blocks DC; reactance decreases as frequency increases
Inductor in AC circuit: passes DC, opposes AC change; reactance increases as frequency increases
Resonance: frequency where capacitive and inductive reactance are equal → maximum energy transfer
Series resistors: R_total = R1 + R2 + … | Parallel resistors: 1/R_total = 1/R1 + 1/R2 + …

Mnemonic — Ohm's Law

Draw a circle. V on top, I and R side by side below. Cover what you want to find: V = I × R.
For power: "PIE" — P = I × E (Watts = Amps × Volts).

Electrical Components

Resistors, capacitors, semiconductors, schematics

4 Qs

▼

Resistor

Limits current; dissipates energy as heat. Color bands = value (ohms).

Capacitor

Stores electric charge. Blocks DC, passes AC. Used in filters and tuned circuits.

Inductor (Coil)

Stores magnetic energy. Passes DC, opposes AC changes. Used in filters and RF chokes.

Diode

One-way current valve. Converts AC to DC (rectification). Zener = voltage regulator.

LED

Light-Emitting Diode. Emits light when forward biased. Polarity matters (anode+/cathode−).

Transistor

Amplifier or switch. BJT types: NPN, PNP. FET: voltage-controlled. 3 terminals.

Transformer

Steps voltage up or down via magnetic coupling. AC only.

IC (Integrated Circuit)

Many components on a chip. Op-amp, voltage regulator, microcontroller, etc.

Resistor color code (0–9): Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Gray, White Mnemonic: "Bad Boys Race Our Young Girls But Violet Generally Wins"
Schematic symbols: know resistor (zigzag), capacitor (parallel lines), inductor (loops), diode (triangle+bar), transistor, battery, ground
Forward bias = diode conducts; reverse bias = diode blocks
PNP vs NPN transistor: current flows in opposite directions; exam usually just asks which type is shown or what it does
Potentiometer: variable resistor (e.g., volume knob)
Electrolytic capacitor: polarized (+ and − must be correct); used for large capacitance at low frequencies

Station Equipment & Troubleshooting

SWR, meters, RFI, common problems

4 Qs

▼

SWR (Standing Wave Ratio): measures impedance mismatch between transmitter, feed line, and antenna 1:1 = perfect | 2:1 = 11% reflected power (usually OK) | High SWR can damage final amplifier
SWR meter placement: between transmitter output and feed line
RF power meter: measures forward and reflected power; can calculate SWR
Squelch: circuit that mutes receiver when signal drops below threshold — prevents noise when no signal
AGC (Automatic Gain Control): keeps audio level consistent regardless of signal strength
Intermodulation distortion (IMD): two strong signals mix in receiver front end → spurious signals at wrong frequencies
Overloading: too-strong signal at receiver input → distortion, desense
Spurious emissions: unintended signals on wrong frequencies from transmitter — keep transmitter clean
RFI in consumer gear: add ferrite choke (bead) on cable near the device; add bypass capacitors
RFI on phone/audio gear: RF entering audio wiring — common cause: antenna near equipment
No RF output troubleshooting steps: check PTT (keying), power, antenna connection, SWR
Hum in audio: often ground loop — use audio isolation transformer or single-point ground
Spectrum analyzer: shows frequency vs. amplitude — used to see spurious outputs
Oscilloscope: shows voltage vs. time — checks waveform shape
Multimeter: measures voltage, current, resistance; most common test gear in ham shack

Common Gotchas

SWR of 1:1 is ideal — exam may ask "what does high SWR indicate?" = antenna mismatch
Ferrite chokes go on cables at the device, not at the transmitter
IMD and overloading are receive-side problems; spurious emissions are transmit-side

Modes, Satellites & Activities

Phone, digital, APRS, satellites, special ops

4 Qs

▼

AM (Amplitude Modulation): older; voice info in amplitude; double-sideband full carrier
FM (Frequency Modulation): most common on VHF/UHF repeaters; audio info in frequency variation
SSB (Single Sideband): HF voice mode; most efficient; USB on 10m, 15m, 20m; LSB on 40m, 80m
CW: Morse code; oldest mode; works in terrible conditions; no minimum speed required
RTTY: radioteletype; legacy digital; still used in contests
PSK31: digital mode; narrow bandwidth; keyboard-to-keyboard
FT8/FT4: weak-signal digital; automated; 15-sec or 7.5-sec cycles; extremely popular on HF
JS8Call: keyboard-to-keyboard messaging using FT8 waveform
Winlink: email over radio; uses VARA, PACTOR, Packet; popular in EmComm
APRS (Automatic Packet Reporting System): real-time position + data via 144.390 MHz (US); packets to internet via igates
Packet radio: AX.25 protocol; uses TNC (terminal node controller)
D-STAR / DMR / Fusion: digital voice modes; use repeaters or hotspots; worldwide linking
Satellites — Technician can operate: must use correct uplink frequency and account for Doppler shift
Doppler shift: satellite approaching = uplink frequency appears higher; moving away = lower. Compensate manually or with software
ISS (International Space Station): 145.800 MHz downlink (voice/APRS); 144.490 APRS uplink (approx) — verify current
ATV (Amateur Television): sends video + audio over radio; typically UHF
Spread spectrum: signal spread across wide bandwidth; low probability of detection; Part 97 allows it
Mesh networking (AREDN): IP networking over amateur radio; used in EmComm

Mode quick memory

FM = FM radio feel (VHF/UHF, repeaters, clear audio)
SSB = serious HF (efficient, HF DX, contests)
FT8 = computer talks (weak signal, automated, HF)
APRS = blips on a map (GPS tracking, 144.390)

Antennas & Feed Lines

Dipole, vertical, coax, SWR

2 Qs

▼

Half-wave dipole length: 468 / f(MHz) feet total (234 ft per leg)
Quarter-wave vertical: 234 / f(MHz) feet; requires ground plane (radials)
Yagi (beam antenna): directional; gain over dipole; has driven element, reflector, directors
Gain antenna: focuses energy in one direction — appears to increase ERP (effective radiated power)
Omni-directional: radiates equally in all horizontal directions (dipole broadside, vertical)
Feed point impedance: dipole ≈ 72Ω; matched to 50Ω coax with slight detuning or balun
Coaxial cable (coax): standard amateur feed line; 50Ω (RG-8, RG-8X, RG-213, LMR-400) or 75Ω (TV cable — less common)
Coax loss: increases with frequency and cable length; use lower-loss cable for long runs on UHF
Open-wire / ladder line: very low loss; must be kept away from metal; requires antenna tuner
Balun: Balanced-to-Unbalanced transformer; connects balanced antenna (dipole) to unbalanced coax; reduces RF on shield
Antenna tuner (ATU): matches impedance between transceiver and feed line; does NOT reduce SWR on coax between tuner and antenna
SWR rises when: antenna is wrong length, bad connection, damaged coax, wrong frequency

Electrical & RF Safety

RF exposure, grounding, tower safety, electrical hazards

3 Qs

▼

RF exposure (MPE): Maximum Permissible Exposure limits protect people near antennas Controlled environment (operators/aware people) = higher limit | Uncontrolled (general public) = lower, more conservative limit
Duty cycle affects RF exposure: FM = 100%, SSB ≈ 20%, CW ≈ 40% — lower duty cycle = less average RF exposure
RF exposure evaluation: required by FCC when you change antenna, power, or mode significantly; use ARRL/FCC online calculators
Distance from antenna: increasing distance dramatically reduces RF exposure (inverse square law)
Safety ground: connect chassis to earth ground — protects against shock from equipment faults
Lightning protection: disconnect coax from radio AND ground the antenna feed line when not in use; use surge protectors rated for RF
NEVER install antenna near power lines — antenna or mast falling into lines = lethal
Tower safety: always use a safety harness; never climb alone; inspect before climbing; respect load limits
Lead-acid battery hazard: produces hydrogen gas during charging — ventilate the area; no sparks
High-voltage capacitors: retain lethal charge after power is removed — discharge before working on equipment
Fuse protection: fuse the positive wire as close to the battery as possible
RF burns: touching an active antenna can cause RF burns — keep away from transmitting antennas
Electrical shock path: current flows hand-to-hand or hand-to-foot through the body — keep one hand in pocket near HV

Safety Questions Are Free Points — Don't Miss These

The answer to "how to reduce RF exposure" is almost always: increase distance, reduce power, or use directional antenna pointed away
Duty cycle question: FM is highest (100%), not lowest
Lead-acid batteries → hydrogen gas → no sparks/flames → ventilate
Never trust a capacitor to be discharged — always verify with meter