Ham Radio Extra cheat sheet

Extra Class licensees may operate all authorized amateur bands and all permitted emission types; no additional frequency segments are reserved exclusively for Extra Class holders.

Amateur license terms are 10 years and may be renewed; the FCC grants a 2-year grace period after expiration during which the license can be renewed without re-examination.

Third-party communications are permitted on phone only when the amateur is not transmitting messages for hire and, for messages originated by a non-amateur, the control operator must be present at the control point.

International communications are limited to messages of a technical nature or remarks of a personal character; no encoded messages intended to obscure meaning, except for control commands and satellite telemetry.

The control operator is responsible for the proper operation of the station regardless of whether control is local, remote, or automatic.

Automatic control may be used on specified bands and modes for beacon, repeater, auxiliary, and space-station operation; it is not permitted for general phone contacts on most HF bands.

Emission types are designated by ITU symbols (e.g., J3E for SSB phone, A1A for CW); bandwidth and mode must fall within the privileges of the license class and band.

The FCC may impose a monetary forfeiture and license suspension or revocation for willful or repeated violations; the standard fine schedule is published in 47 CFR 1.80.

Amateur stations must not cause harmful interference and must accept interference from authorized services; the station must cease operation if it causes interference to a primary service.

Use the phonetic alphabet (Alfa, Bravo, Charlie...) for call signs and signal reports to improve intelligibility under weak or noisy conditions.

The Q signal RST system reports Readability (1-5), Strength (1-9), and Tone (1-9 for CW); SSB reports omit tone and use R and S only.

A net control station manages check-ins and traffic; formal traffic uses preamble elements: message number, precedence, station of origin, check, and place of origin.

Precedence levels for message handling are Emergency (life/property), Priority (urgent), Routine, and Welfare (inquiry about disaster victims).

Split operation means transmitting on one frequency and listening on another; state the listening frequency clearly and use the correct VFO mode.

For VHF/UHF repeaters, the standard offset is 600 kHz on 2 m and 5 MHz on 70 cm; CTCSS tones are used to access closed repeaters.

When calling CQ, transmit the call sign at the beginning and end of the call; identify at least every 10 minutes and at the end of each communication.

Use of the word "break" or "break-break" is reserved for emergency or priority traffic; routine interruptions should wait for a pause in the conversation.

Amateur satellites use uplink and downlink bands; full-duplex operation with separate VFOs is standard, and Doppler shift requires retuning during a pass.

Ohm's law: V = I × R; power: P = V × I = I²R = V²/R.

Impedance is the vector sum of resistance and reactance: Z = R + jX; reactance of a capacitor is Xc = 1/(2πfC) and of an inductor is Xl = 2πfL.

Resonance occurs when Xl = Xc, giving f = 1/(2π√(LC)); at resonance the circuit presents only resistance.

Decibels: dB = 10 log(P2/P1) for power and 20 log(V2/V1) for voltage; a 3 dB change is a factor of 2 in power.

The skin effect concentrates RF current near the conductor surface; effective resistance rises with frequency and with conductor diameter reduction.

A Class A amplifier conducts for the full 360° of the cycle and is linear but inefficient; Class B conducts 180°, Class C less than 180° and is nonlinear.

FM modulation index β = deviation / modulating frequency; Carson's rule estimates bandwidth as 2(β + 1) × modulating frequency.

A mixer produces sum and difference frequencies; the difference product is used for superheterodyne reception and the sum for up-conversion.

Noise figure relates signal-to-noise degradation: NF(dB) = 10 log(F), and cascaded stages are dominated by the first stage's gain and noise figure.

A half-wave dipole in free space has a feedpoint impedance near 73 Ω and 2.15 dBi gain; a quarter-wave vertical over a perfect ground plane is about 36 Ω.

Antenna gain is directional: dBi references an isotropic radiator, dBd references a dipole, and dBd = dBi − 2.15.

A 1/4-wave vertical requires a counterpoise or ground plane; a 5/8-wave vertical has higher gain but needs a matching network at the base.

Characteristic impedance of coax is approximately Z0 = (138/√εr) log(D/d); of a parallel line, Z0 = 276 log(2S/d).

VSWR = (1 + |Γ|)/(1 − |Γ|); a 2:1 VSWR corresponds to a reflection coefficient of 0.333 and about 11% reflected power.

A half-wave transmission line repeats the load impedance; a quarter-wave line transforms impedance as Zin = Z0²/Zload.

The impedance of a transmission line varies with electrical length; open and short stubs are used for matching and are selected by their electrical length.

RF exposure is evaluated against maximum permissible exposure (MPE) limits for electric and magnetic field strength and power density, averaged over 6 minutes for controlled environments.

Controlled environments (occupational) allow higher MPE than uncontrolled (general population) environments; the general-population limit for 2 m is about 1 mW/cm² averaged over 30 minutes.

Extra Class licensees may operate all authorized amateur bands and all permitted emission types; no additional frequency segments are reserved exclusively for Extra Class holders.

Amateur license terms are 10 years and may be renewed; the FCC grants a 2-year grace period after expiration during which the license can be renewed without re-examination.

Third-party communications are permitted on phone only when the amateur is not transmitting messages for hire and, for messages originated by a non-amateur, the control operator must be present at the control point.

International communications are limited to messages of a technical nature or remarks of a personal character; no encoded messages intended to obscure meaning, except for control commands and satellite telemetry.

The control operator is responsible for the proper operation of the station regardless of whether control is local, remote, or automatic.

Automatic control may be used on specified bands and modes for beacon, repeater, auxiliary, and space-station operation; it is not permitted for general phone contacts on most HF bands.

Emission types are designated by ITU symbols (e.g., J3E for SSB phone, A1A for CW); bandwidth and mode must fall within the privileges of the license class and band.

The FCC may impose a monetary forfeiture and license suspension or revocation for willful or repeated violations; the standard fine schedule is published in 47 CFR 1.80.

Amateur stations must not cause harmful interference and must accept interference from authorized services; the station must cease operation if it causes interference to a primary service.

Use the phonetic alphabet (Alfa, Bravo, Charlie...) for call signs and signal reports to improve intelligibility under weak or noisy conditions.

The Q signal RST system reports Readability (1-5), Strength (1-9), and Tone (1-9 for CW); SSB reports omit tone and use R and S only.

A net control station manages check-ins and traffic; formal traffic uses preamble elements: message number, precedence, station of origin, check, and place of origin.

Precedence levels for message handling are Emergency (life/property), Priority (urgent), Routine, and Welfare (inquiry about disaster victims).

Split operation means transmitting on one frequency and listening on another; state the listening frequency clearly and use the correct VFO mode.

For VHF/UHF repeaters, the standard offset is 600 kHz on 2 m and 5 MHz on 70 cm; CTCSS tones are used to access closed repeaters.

When calling CQ, transmit the call sign at the beginning and end of the call; identify at least every 10 minutes and at the end of each communication.

Use of the word "break" or "break-break" is reserved for emergency or priority traffic; routine interruptions should wait for a pause in the conversation.

Amateur satellites use uplink and downlink bands; full-duplex operation with separate VFOs is standard, and Doppler shift requires retuning during a pass.

Ohm's law: V = I × R; power: P = V × I = I²R = V²/R.

Impedance is the vector sum of resistance and reactance: Z = R + jX; reactance of a capacitor is Xc = 1/(2πfC) and of an inductor is Xl = 2πfL.

Resonance occurs when Xl = Xc, giving f = 1/(2π√(LC)); at resonance the circuit presents only resistance.

Decibels: dB = 10 log(P2/P1) for power and 20 log(V2/V1) for voltage; a 3 dB change is a factor of 2 in power.

The skin effect concentrates RF current near the conductor surface; effective resistance rises with frequency and with conductor diameter reduction.

A Class A amplifier conducts for the full 360° of the cycle and is linear but inefficient; Class B conducts 180°, Class C less than 180° and is nonlinear.

FM modulation index β = deviation / modulating frequency; Carson's rule estimates bandwidth as 2(β + 1) × modulating frequency.

A mixer produces sum and difference frequencies; the difference product is used for superheterodyne reception and the sum for up-conversion.

Noise figure relates signal-to-noise degradation: NF(dB) = 10 log(F), and cascaded stages are dominated by the first stage's gain and noise figure.

A half-wave dipole in free space has a feedpoint impedance near 73 Ω and 2.15 dBi gain; a quarter-wave vertical over a perfect ground plane is about 36 Ω.

Antenna gain is directional: dBi references an isotropic radiator, dBd references a dipole, and dBd = dBi − 2.15.

A 1/4-wave vertical requires a counterpoise or ground plane; a 5/8-wave vertical has higher gain but needs a matching network at the base.

Characteristic impedance of coax is approximately Z0 = (138/√εr) log(D/d); of a parallel line, Z0 = 276 log(2S/d).

VSWR = (1 + |Γ|)/(1 − |Γ|); a 2:1 VSWR corresponds to a reflection coefficient of 0.333 and about 11% reflected power.

A half-wave transmission line repeats the load impedance; a quarter-wave line transforms impedance as Zin = Z0²/Zload.

The impedance of a transmission line varies with electrical length; open and short stubs are used for matching and are selected by their electrical length.

RF exposure is evaluated against maximum permissible exposure (MPE) limits for electric and magnetic field strength and power density, averaged over 6 minutes for controlled environments.

Controlled environments (occupational) allow higher MPE than uncontrolled (general population) environments; the general-population limit for 2 m is about 1 mW/cm² averaged over 30 minutes.