Ham Radio Technician cheat sheet

Part 97 defines the Amateur Radio Service as a voluntary, noncommercial service of self-training, intercommunication, and technical investigation, with no pecuniary interest and no broadcasting.

The FCC issues three license classes: Technician, General, and Amateur Extra. Each license term is 10 years and may be renewed within the 90-day window before expiration; a two-year grace period follows expiration, but operation is not permitted until renewal is granted.

Technician privileges include all amateur bands above 30 MHz, plus limited HF access: CW on 80, 40, and 15 m, and data on 80, 40, and 15 m, all within the Novice-class subbands; power is limited to 1500 W PEP output.

Control operator types are local, remote, and automatic (repeater or auxiliary station). The control operator is responsible for the proper operation of the station, and the station must have a control point.

Identification: transmit your FCC-assigned call sign at the beginning and end of each communication and at least every 10 minutes during it; use phone (voice), CW, or digital identification, and identify with the call sign of the station you are operating.

Third-party communications are messages sent between two amateur stations on behalf of a third party; they are permitted only when the third party's country has a third-party agreement with the US, and never for business or pecuniary interest.

Prohibited transmissions include obscene or indecent language, music (except incidental to an authorized retransmission), commercial advertising, and communications for hire or material compensation; business use is generally prohibited.

The FCC may inspect your station and records upon request. You must keep a copy of your license (or FCC ULS record) available, and repeater or auxiliary stations must maintain records of control-point location and control operator.

Frequency coordination is voluntary for repeaters; the FCC does not assign repeater frequencies, but the recognized frequency coordinator's recommendation is generally followed to minimize interference.

Use the phonetic alphabet (Alfa, Bravo, Charlie, Delta, Echo, Foxtrot, Golf, Hotel, India, Juliett, Kilo, Lima, Mike, November, Oscar, Papa, Quebec, Romeo, Sierra, Tango, Uniform, Victor, Whiskey, X-ray, Yankee, Zulu) to spell call signs and unfamiliar words.

Calling procedure: listen first, then call the other station with its call sign followed by your own; use "CQ" to call any station, and respond with the calling station's call sign followed by yours.

RST system: R (readability 1-5), S (signal strength 1-9), T (tone 1-9, used for CW). Phone reports usually give R and S; CW reports include T.

Repeater operation: offset (standard 600 kHz on 2 m, 5 MHz on 70 cm), CTCSS tone or DCS code to access the repeater, and the courtesy tone indicates the repeater is ready for the next transmission.

Emergency traffic: use "MAYDAY" (from French m'aidez) on voice and "SOS" on CW; emergency communications may be transmitted on any frequency, and the FCC permits operation outside normal privileges during a bona fide emergency.

Net control stations direct net traffic; check in with your call sign, follow the net control's instructions, and use tactical call signs only if the net permits them.

Q signals: QRM (man-made interference), QRN (atmospheric noise), QSB (fading), QSL (acknowledgment), QSY (change frequency), QTH (location), QRT (stop transmitting).

Station control: the control operator must be able to disable the transmitter remotely; automatic control is allowed for repeaters, auxiliary stations, and certain digital stations, but the control operator remains responsible.

Logging is not required for most amateur operation, but keeping a log is useful for awards (DXCC, WAS) and for resolving interference complaints; some digital modes and contests require it.

Ohm's Law: V = I × R, I = V / R, R = V / I. Power: P = V × I = I²R = V²/R. These apply to DC circuits and to resistive AC circuits.

Series resistance: R_total = R1 + R2 + ...; parallel resistance: 1/R_total = 1/R1 + 1/R2 + ...; for two resistors, R_total = (R1 × R2) / (R1 + R2).

Capacitive reactance Xc = 1 / (2πfC); inductive reactance Xl = 2πfL. Reactance increases with frequency for capacitors and decreases for inductors.

Resonance occurs when Xl = Xc, giving f = 1 / (2π√(LC)). At resonance, a series circuit has minimum impedance and a parallel circuit has maximum impedance.

Decibels: dB = 10 log10(P2/P1) for power; dB = 20 log10(V2/V1) for voltage. A 3 dB increase doubles power; a 10 dB increase multiplies power by 10.

Wavelength: λ (meters) = 300 / f (MHz). A half-wave dipole is about 468 / f (MHz) feet long; a quarter-wave vertical is about 234 / f (MHz) feet.

Frequency bands: HF 3-30 MHz, VHF 30-300 MHz, UHF 300-3000 MHz. The 2 m band is 144-148 MHz; the 70 cm band is 420-450 MHz.

Modulation: AM varies amplitude, FM varies frequency, SSB is amplitude modulation with one sideband and suppressed carrier, and CW is on-off keying of a carrier.

The ionosphere (D, E, F1, F2 layers) refracts HF signals; the F2 layer supports long-distance skip, and the D layer absorbs lower HF signals during daylight.

Transceiver: a combined transmitter and receiver. A transverter converts one band to another; a linear amplifier increases power and must be rated for the mode used (SSB, CW, FM).

SWR (standing wave ratio) measures impedance match; 1:1 is ideal, below 2:1 is generally acceptable, and above 3:1 may cause transmitter protection to reduce power. Use an SWR meter or antenna analyzer.

Balun (balanced-to-unbalanced) matches a balanced antenna to an unbalanced feed line; an unun matches unbalanced to unbalanced. A 1:1 balun is used with dipoles fed by coax.

Feed lines: coax has loss that increases with frequency; ladder line and open-wire feeders have lower loss but require a tuner and balanced antenna.

Antenna types: half-wave dipole (fed at center, about 73 ohms), quarter-wave vertical with ground plane, Yagi-Uda (directional, gain from parasitic elements), and loop antennas.

Polarization: horizontal for dipoles and Yagis, vertical for most mobile and repeater antennas. Cross-polarization causes significant signal loss.

FM deviation: narrowband FM uses ±5 kHz deviation on 2 m and 70 cm; wideband FM is used for broadcast. CTCSS tones are subaudible tones used to access repeaters.

Digital modes: FT8 (15-second cycles, weak-signal), PSK31 (narrowband keyboard-to-keyboard), RTTY (frequency-shift keying), and packet radio (AX.25). They require audio interface and PTT control.

Power and safety: RF exposure limits are frequency-dependent (MPE limits in FCC OET Bulletin 65); avoid contact with antennas, use proper grounding, and never transmit into an antenna with high SWR without checking the match.

Part 97 defines the Amateur Radio Service as a voluntary, noncommercial service of self-training, intercommunication, and technical investigation, with no pecuniary interest and no broadcasting.

The FCC issues three license classes: Technician, General, and Amateur Extra. Each license term is 10 years and may be renewed within the 90-day window before expiration; a two-year grace period follows expiration, but operation is not permitted until renewal is granted.

Technician privileges include all amateur bands above 30 MHz, plus limited HF access: CW on 80, 40, and 15 m, and data on 80, 40, and 15 m, all within the Novice-class subbands; power is limited to 1500 W PEP output.

Control operator types are local, remote, and automatic (repeater or auxiliary station). The control operator is responsible for the proper operation of the station, and the station must have a control point.

Identification: transmit your FCC-assigned call sign at the beginning and end of each communication and at least every 10 minutes during it; use phone (voice), CW, or digital identification, and identify with the call sign of the station you are operating.

Third-party communications are messages sent between two amateur stations on behalf of a third party; they are permitted only when the third party's country has a third-party agreement with the US, and never for business or pecuniary interest.

Prohibited transmissions include obscene or indecent language, music (except incidental to an authorized retransmission), commercial advertising, and communications for hire or material compensation; business use is generally prohibited.

The FCC may inspect your station and records upon request. You must keep a copy of your license (or FCC ULS record) available, and repeater or auxiliary stations must maintain records of control-point location and control operator.

Frequency coordination is voluntary for repeaters; the FCC does not assign repeater frequencies, but the recognized frequency coordinator's recommendation is generally followed to minimize interference.

Use the phonetic alphabet (Alfa, Bravo, Charlie, Delta, Echo, Foxtrot, Golf, Hotel, India, Juliett, Kilo, Lima, Mike, November, Oscar, Papa, Quebec, Romeo, Sierra, Tango, Uniform, Victor, Whiskey, X-ray, Yankee, Zulu) to spell call signs and unfamiliar words.

Calling procedure: listen first, then call the other station with its call sign followed by your own; use "CQ" to call any station, and respond with the calling station's call sign followed by yours.

RST system: R (readability 1-5), S (signal strength 1-9), T (tone 1-9, used for CW). Phone reports usually give R and S; CW reports include T.

Repeater operation: offset (standard 600 kHz on 2 m, 5 MHz on 70 cm), CTCSS tone or DCS code to access the repeater, and the courtesy tone indicates the repeater is ready for the next transmission.

Emergency traffic: use "MAYDAY" (from French m'aidez) on voice and "SOS" on CW; emergency communications may be transmitted on any frequency, and the FCC permits operation outside normal privileges during a bona fide emergency.

Net control stations direct net traffic; check in with your call sign, follow the net control's instructions, and use tactical call signs only if the net permits them.

Q signals: QRM (man-made interference), QRN (atmospheric noise), QSB (fading), QSL (acknowledgment), QSY (change frequency), QTH (location), QRT (stop transmitting).

Station control: the control operator must be able to disable the transmitter remotely; automatic control is allowed for repeaters, auxiliary stations, and certain digital stations, but the control operator remains responsible.

Logging is not required for most amateur operation, but keeping a log is useful for awards (DXCC, WAS) and for resolving interference complaints; some digital modes and contests require it.

Ohm's Law: V = I × R, I = V / R, R = V / I. Power: P = V × I = I²R = V²/R. These apply to DC circuits and to resistive AC circuits.

Series resistance: R_total = R1 + R2 + ...; parallel resistance: 1/R_total = 1/R1 + 1/R2 + ...; for two resistors, R_total = (R1 × R2) / (R1 + R2).

Capacitive reactance Xc = 1 / (2πfC); inductive reactance Xl = 2πfL. Reactance increases with frequency for capacitors and decreases for inductors.

Resonance occurs when Xl = Xc, giving f = 1 / (2π√(LC)). At resonance, a series circuit has minimum impedance and a parallel circuit has maximum impedance.

Decibels: dB = 10 log10(P2/P1) for power; dB = 20 log10(V2/V1) for voltage. A 3 dB increase doubles power; a 10 dB increase multiplies power by 10.

Wavelength: λ (meters) = 300 / f (MHz). A half-wave dipole is about 468 / f (MHz) feet long; a quarter-wave vertical is about 234 / f (MHz) feet.

Frequency bands: HF 3-30 MHz, VHF 30-300 MHz, UHF 300-3000 MHz. The 2 m band is 144-148 MHz; the 70 cm band is 420-450 MHz.

Modulation: AM varies amplitude, FM varies frequency, SSB is amplitude modulation with one sideband and suppressed carrier, and CW is on-off keying of a carrier.

The ionosphere (D, E, F1, F2 layers) refracts HF signals; the F2 layer supports long-distance skip, and the D layer absorbs lower HF signals during daylight.

Transceiver: a combined transmitter and receiver. A transverter converts one band to another; a linear amplifier increases power and must be rated for the mode used (SSB, CW, FM).

SWR (standing wave ratio) measures impedance match; 1:1 is ideal, below 2:1 is generally acceptable, and above 3:1 may cause transmitter protection to reduce power. Use an SWR meter or antenna analyzer.

Balun (balanced-to-unbalanced) matches a balanced antenna to an unbalanced feed line; an unun matches unbalanced to unbalanced. A 1:1 balun is used with dipoles fed by coax.

Feed lines: coax has loss that increases with frequency; ladder line and open-wire feeders have lower loss but require a tuner and balanced antenna.

Antenna types: half-wave dipole (fed at center, about 73 ohms), quarter-wave vertical with ground plane, Yagi-Uda (directional, gain from parasitic elements), and loop antennas.

Polarization: horizontal for dipoles and Yagis, vertical for most mobile and repeater antennas. Cross-polarization causes significant signal loss.

FM deviation: narrowband FM uses ±5 kHz deviation on 2 m and 70 cm; wideband FM is used for broadcast. CTCSS tones are subaudible tones used to access repeaters.

Digital modes: FT8 (15-second cycles, weak-signal), PSK31 (narrowband keyboard-to-keyboard), RTTY (frequency-shift keying), and packet radio (AX.25). They require audio interface and PTT control.

Power and safety: RF exposure limits are frequency-dependent (MPE limits in FCC OET Bulletin 65); avoid contact with antennas, use proper grounding, and never transmit into an antenna with high SWR without checking the match.

Part 97 defines the Amateur Radio Service as a voluntary, noncommercial service of self-training, intercommunication, and technical investigation, with no pecuniary interest and no broadcasting.

The FCC issues three license classes: Technician, General, and Amateur Extra. Each license term is 10 years and may be renewed within the 90-day window before expiration; a two-year grace period follows expiration, but operation is not permitted until renewal is granted.

Technician privileges include all amateur bands above 30 MHz, plus limited HF access: CW on 80, 40, and 15 m, and data on 80, 40, and 15 m, all within the Novice-class subbands; power is limited to 1500 W PEP output.

Control operator types are local, remote, and automatic (repeater or auxiliary station). The control operator is responsible for the proper operation of the station, and the station must have a control point.

Identification: transmit your FCC-assigned call sign at the beginning and end of each communication and at least every 10 minutes during it; use phone (voice), CW, or digital identification, and identify with the call sign of the station you are operating.

Third-party communications are messages sent between two amateur stations on behalf of a third party; they are permitted only when the third party's country has a third-party agreement with the US, and never for business or pecuniary interest.

Prohibited transmissions include obscene or indecent language, music (except incidental to an authorized retransmission), commercial advertising, and communications for hire or material compensation; business use is generally prohibited.

The FCC may inspect your station and records upon request. You must keep a copy of your license (or FCC ULS record) available, and repeater or auxiliary stations must maintain records of control-point location and control operator.

Frequency coordination is voluntary for repeaters; the FCC does not assign repeater frequencies, but the recognized frequency coordinator's recommendation is generally followed to minimize interference.

Use the phonetic alphabet (Alfa, Bravo, Charlie, Delta, Echo, Foxtrot, Golf, Hotel, India, Juliett, Kilo, Lima, Mike, November, Oscar, Papa, Quebec, Romeo, Sierra, Tango, Uniform, Victor, Whiskey, X-ray, Yankee, Zulu) to spell call signs and unfamiliar words.

Calling procedure: listen first, then call the other station with its call sign followed by your own; use "CQ" to call any station, and respond with the calling station's call sign followed by yours.

RST system: R (readability 1-5), S (signal strength 1-9), T (tone 1-9, used for CW). Phone reports usually give R and S; CW reports include T.

Repeater operation: offset (standard 600 kHz on 2 m, 5 MHz on 70 cm), CTCSS tone or DCS code to access the repeater, and the courtesy tone indicates the repeater is ready for the next transmission.

Emergency traffic: use "MAYDAY" (from French m'aidez) on voice and "SOS" on CW; emergency communications may be transmitted on any frequency, and the FCC permits operation outside normal privileges during a bona fide emergency.

Net control stations direct net traffic; check in with your call sign, follow the net control's instructions, and use tactical call signs only if the net permits them.

Q signals: QRM (man-made interference), QRN (atmospheric noise), QSB (fading), QSL (acknowledgment), QSY (change frequency), QTH (location), QRT (stop transmitting).

Station control: the control operator must be able to disable the transmitter remotely; automatic control is allowed for repeaters, auxiliary stations, and certain digital stations, but the control operator remains responsible.

Logging is not required for most amateur operation, but keeping a log is useful for awards (DXCC, WAS) and for resolving interference complaints; some digital modes and contests require it.

Ohm's Law: V = I × R, I = V / R, R = V / I. Power: P = V × I = I²R = V²/R. These apply to DC circuits and to resistive AC circuits.

Series resistance: R_total = R1 + R2 + ...; parallel resistance: 1/R_total = 1/R1 + 1/R2 + ...; for two resistors, R_total = (R1 × R2) / (R1 + R2).

Capacitive reactance Xc = 1 / (2πfC); inductive reactance Xl = 2πfL. Reactance increases with frequency for capacitors and decreases for inductors.

Resonance occurs when Xl = Xc, giving f = 1 / (2π√(LC)). At resonance, a series circuit has minimum impedance and a parallel circuit has maximum impedance.

Decibels: dB = 10 log10(P2/P1) for power; dB = 20 log10(V2/V1) for voltage. A 3 dB increase doubles power; a 10 dB increase multiplies power by 10.

Wavelength: λ (meters) = 300 / f (MHz). A half-wave dipole is about 468 / f (MHz) feet long; a quarter-wave vertical is about 234 / f (MHz) feet.

Frequency bands: HF 3-30 MHz, VHF 30-300 MHz, UHF 300-3000 MHz. The 2 m band is 144-148 MHz; the 70 cm band is 420-450 MHz.

Modulation: AM varies amplitude, FM varies frequency, SSB is amplitude modulation with one sideband and suppressed carrier, and CW is on-off keying of a carrier.

The ionosphere (D, E, F1, F2 layers) refracts HF signals; the F2 layer supports long-distance skip, and the D layer absorbs lower HF signals during daylight.

Transceiver: a combined transmitter and receiver. A transverter converts one band to another; a linear amplifier increases power and must be rated for the mode used (SSB, CW, FM).

SWR (standing wave ratio) measures impedance match; 1:1 is ideal, below 2:1 is generally acceptable, and above 3:1 may cause transmitter protection to reduce power. Use an SWR meter or antenna analyzer.

Balun (balanced-to-unbalanced) matches a balanced antenna to an unbalanced feed line; an unun matches unbalanced to unbalanced. A 1:1 balun is used with dipoles fed by coax.

Feed lines: coax has loss that increases with frequency; ladder line and open-wire feeders have lower loss but require a tuner and balanced antenna.

Antenna types: half-wave dipole (fed at center, about 73 ohms), quarter-wave vertical with ground plane, Yagi-Uda (directional, gain from parasitic elements), and loop antennas.

Polarization: horizontal for dipoles and Yagis, vertical for most mobile and repeater antennas. Cross-polarization causes significant signal loss.

FM deviation: narrowband FM uses ±5 kHz deviation on 2 m and 70 cm; wideband FM is used for broadcast. CTCSS tones are subaudible tones used to access repeaters.

Digital modes: FT8 (15-second cycles, weak-signal), PSK31 (narrowband keyboard-to-keyboard), RTTY (frequency-shift keying), and packet radio (AX.25). They require audio interface and PTT control.

Power and safety: RF exposure limits are frequency-dependent (MPE limits in FCC OET Bulletin 65); avoid contact with antennas, use proper grounding, and never transmit into an antenna with high SWR without checking the match.

Part 97 defines the Amateur Radio Service as a voluntary, noncommercial service of self-training, intercommunication, and technical investigation, with no pecuniary interest and no broadcasting.

The FCC issues three license classes: Technician, General, and Amateur Extra. Each license term is 10 years and may be renewed within the 90-day window before expiration; a two-year grace period follows expiration, but operation is not permitted until renewal is granted.

Technician privileges include all amateur bands above 30 MHz, plus limited HF access: CW on 80, 40, and 15 m, and data on 80, 40, and 15 m, all within the Novice-class subbands; power is limited to 1500 W PEP output.

Control operator types are local, remote, and automatic (repeater or auxiliary station). The control operator is responsible for the proper operation of the station, and the station must have a control point.

Identification: transmit your FCC-assigned call sign at the beginning and end of each communication and at least every 10 minutes during it; use phone (voice), CW, or digital identification, and identify with the call sign of the station you are operating.

Third-party communications are messages sent between two amateur stations on behalf of a third party; they are permitted only when the third party's country has a third-party agreement with the US, and never for business or pecuniary interest.

Prohibited transmissions include obscene or indecent language, music (except incidental to an authorized retransmission), commercial advertising, and communications for hire or material compensation; business use is generally prohibited.

The FCC may inspect your station and records upon request. You must keep a copy of your license (or FCC ULS record) available, and repeater or auxiliary stations must maintain records of control-point location and control operator.

Frequency coordination is voluntary for repeaters; the FCC does not assign repeater frequencies, but the recognized frequency coordinator's recommendation is generally followed to minimize interference.

Use the phonetic alphabet (Alfa, Bravo, Charlie, Delta, Echo, Foxtrot, Golf, Hotel, India, Juliett, Kilo, Lima, Mike, November, Oscar, Papa, Quebec, Romeo, Sierra, Tango, Uniform, Victor, Whiskey, X-ray, Yankee, Zulu) to spell call signs and unfamiliar words.

Calling procedure: listen first, then call the other station with its call sign followed by your own; use "CQ" to call any station, and respond with the calling station's call sign followed by yours.

RST system: R (readability 1-5), S (signal strength 1-9), T (tone 1-9, used for CW). Phone reports usually give R and S; CW reports include T.

Repeater operation: offset (standard 600 kHz on 2 m, 5 MHz on 70 cm), CTCSS tone or DCS code to access the repeater, and the courtesy tone indicates the repeater is ready for the next transmission.

Emergency traffic: use "MAYDAY" (from French m'aidez) on voice and "SOS" on CW; emergency communications may be transmitted on any frequency, and the FCC permits operation outside normal privileges during a bona fide emergency.

Net control stations direct net traffic; check in with your call sign, follow the net control's instructions, and use tactical call signs only if the net permits them.

Q signals: QRM (man-made interference), QRN (atmospheric noise), QSB (fading), QSL (acknowledgment), QSY (change frequency), QTH (location), QRT (stop transmitting).

Station control: the control operator must be able to disable the transmitter remotely; automatic control is allowed for repeaters, auxiliary stations, and certain digital stations, but the control operator remains responsible.

Logging is not required for most amateur operation, but keeping a log is useful for awards (DXCC, WAS) and for resolving interference complaints; some digital modes and contests require it.

Ohm's Law: V = I × R, I = V / R, R = V / I. Power: P = V × I = I²R = V²/R. These apply to DC circuits and to resistive AC circuits.

Series resistance: R_total = R1 + R2 + ...; parallel resistance: 1/R_total = 1/R1 + 1/R2 + ...; for two resistors, R_total = (R1 × R2) / (R1 + R2).

Capacitive reactance Xc = 1 / (2πfC); inductive reactance Xl = 2πfL. Reactance increases with frequency for capacitors and decreases for inductors.

Resonance occurs when Xl = Xc, giving f = 1 / (2π√(LC)). At resonance, a series circuit has minimum impedance and a parallel circuit has maximum impedance.

Decibels: dB = 10 log10(P2/P1) for power; dB = 20 log10(V2/V1) for voltage. A 3 dB increase doubles power; a 10 dB increase multiplies power by 10.

Wavelength: λ (meters) = 300 / f (MHz). A half-wave dipole is about 468 / f (MHz) feet long; a quarter-wave vertical is about 234 / f (MHz) feet.

Frequency bands: HF 3-30 MHz, VHF 30-300 MHz, UHF 300-3000 MHz. The 2 m band is 144-148 MHz; the 70 cm band is 420-450 MHz.

Modulation: AM varies amplitude, FM varies frequency, SSB is amplitude modulation with one sideband and suppressed carrier, and CW is on-off keying of a carrier.

The ionosphere (D, E, F1, F2 layers) refracts HF signals; the F2 layer supports long-distance skip, and the D layer absorbs lower HF signals during daylight.

Transceiver: a combined transmitter and receiver. A transverter converts one band to another; a linear amplifier increases power and must be rated for the mode used (SSB, CW, FM).

SWR (standing wave ratio) measures impedance match; 1:1 is ideal, below 2:1 is generally acceptable, and above 3:1 may cause transmitter protection to reduce power. Use an SWR meter or antenna analyzer.

Balun (balanced-to-unbalanced) matches a balanced antenna to an unbalanced feed line; an unun matches unbalanced to unbalanced. A 1:1 balun is used with dipoles fed by coax.

Feed lines: coax has loss that increases with frequency; ladder line and open-wire feeders have lower loss but require a tuner and balanced antenna.

Antenna types: half-wave dipole (fed at center, about 73 ohms), quarter-wave vertical with ground plane, Yagi-Uda (directional, gain from parasitic elements), and loop antennas.

Polarization: horizontal for dipoles and Yagis, vertical for most mobile and repeater antennas. Cross-polarization causes significant signal loss.

FM deviation: narrowband FM uses ±5 kHz deviation on 2 m and 70 cm; wideband FM is used for broadcast. CTCSS tones are subaudible tones used to access repeaters.

Digital modes: FT8 (15-second cycles, weak-signal), PSK31 (narrowband keyboard-to-keyboard), RTTY (frequency-shift keying), and packet radio (AX.25). They require audio interface and PTT control.

Power and safety: RF exposure limits are frequency-dependent (MPE limits in FCC OET Bulletin 65); avoid contact with antennas, use proper grounding, and never transmit into an antenna with high SWR without checking the match.

Part 97 defines the Amateur Radio Service as a voluntary, noncommercial service of self-training, intercommunication, and technical investigation, with no pecuniary interest and no broadcasting.

The FCC issues three license classes: Technician, General, and Amateur Extra. Each license term is 10 years and may be renewed within the 90-day window before expiration; a two-year grace period follows expiration, but operation is not permitted until renewal is granted.

Technician privileges include all amateur bands above 30 MHz, plus limited HF access: CW on 80, 40, and 15 m, and data on 80, 40, and 15 m, all within the Novice-class subbands; power is limited to 1500 W PEP output.

Control operator types are local, remote, and automatic (repeater or auxiliary station). The control operator is responsible for the proper operation of the station, and the station must have a control point.

Identification: transmit your FCC-assigned call sign at the beginning and end of each communication and at least every 10 minutes during it; use phone (voice), CW, or digital identification, and identify with the call sign of the station you are operating.

Third-party communications are messages sent between two amateur stations on behalf of a third party; they are permitted only when the third party's country has a third-party agreement with the US, and never for business or pecuniary interest.

Prohibited transmissions include obscene or indecent language, music (except incidental to an authorized retransmission), commercial advertising, and communications for hire or material compensation; business use is generally prohibited.

The FCC may inspect your station and records upon request. You must keep a copy of your license (or FCC ULS record) available, and repeater or auxiliary stations must maintain records of control-point location and control operator.

Frequency coordination is voluntary for repeaters; the FCC does not assign repeater frequencies, but the recognized frequency coordinator's recommendation is generally followed to minimize interference.

Use the phonetic alphabet (Alfa, Bravo, Charlie, Delta, Echo, Foxtrot, Golf, Hotel, India, Juliett, Kilo, Lima, Mike, November, Oscar, Papa, Quebec, Romeo, Sierra, Tango, Uniform, Victor, Whiskey, X-ray, Yankee, Zulu) to spell call signs and unfamiliar words.

Calling procedure: listen first, then call the other station with its call sign followed by your own; use "CQ" to call any station, and respond with the calling station's call sign followed by yours.

RST system: R (readability 1-5), S (signal strength 1-9), T (tone 1-9, used for CW). Phone reports usually give R and S; CW reports include T.

Repeater operation: offset (standard 600 kHz on 2 m, 5 MHz on 70 cm), CTCSS tone or DCS code to access the repeater, and the courtesy tone indicates the repeater is ready for the next transmission.

Emergency traffic: use "MAYDAY" (from French m'aidez) on voice and "SOS" on CW; emergency communications may be transmitted on any frequency, and the FCC permits operation outside normal privileges during a bona fide emergency.

Net control stations direct net traffic; check in with your call sign, follow the net control's instructions, and use tactical call signs only if the net permits them.

Q signals: QRM (man-made interference), QRN (atmospheric noise), QSB (fading), QSL (acknowledgment), QSY (change frequency), QTH (location), QRT (stop transmitting).

Station control: the control operator must be able to disable the transmitter remotely; automatic control is allowed for repeaters, auxiliary stations, and certain digital stations, but the control operator remains responsible.

Logging is not required for most amateur operation, but keeping a log is useful for awards (DXCC, WAS) and for resolving interference complaints; some digital modes and contests require it.

Ohm's Law: V = I × R, I = V / R, R = V / I. Power: P = V × I = I²R = V²/R. These apply to DC circuits and to resistive AC circuits.

Series resistance: R_total = R1 + R2 + ...; parallel resistance: 1/R_total = 1/R1 + 1/R2 + ...; for two resistors, R_total = (R1 × R2) / (R1 + R2).

Capacitive reactance Xc = 1 / (2πfC); inductive reactance Xl = 2πfL. Reactance increases with frequency for capacitors and decreases for inductors.

Resonance occurs when Xl = Xc, giving f = 1 / (2π√(LC)). At resonance, a series circuit has minimum impedance and a parallel circuit has maximum impedance.

Decibels: dB = 10 log10(P2/P1) for power; dB = 20 log10(V2/V1) for voltage. A 3 dB increase doubles power; a 10 dB increase multiplies power by 10.

Wavelength: λ (meters) = 300 / f (MHz). A half-wave dipole is about 468 / f (MHz) feet long; a quarter-wave vertical is about 234 / f (MHz) feet.

Frequency bands: HF 3-30 MHz, VHF 30-300 MHz, UHF 300-3000 MHz. The 2 m band is 144-148 MHz; the 70 cm band is 420-450 MHz.

Modulation: AM varies amplitude, FM varies frequency, SSB is amplitude modulation with one sideband and suppressed carrier, and CW is on-off keying of a carrier.

The ionosphere (D, E, F1, F2 layers) refracts HF signals; the F2 layer supports long-distance skip, and the D layer absorbs lower HF signals during daylight.

Transceiver: a combined transmitter and receiver. A transverter converts one band to another; a linear amplifier increases power and must be rated for the mode used (SSB, CW, FM).

SWR (standing wave ratio) measures impedance match; 1:1 is ideal, below 2:1 is generally acceptable, and above 3:1 may cause transmitter protection to reduce power. Use an SWR meter or antenna analyzer.

Balun (balanced-to-unbalanced) matches a balanced antenna to an unbalanced feed line; an unun matches unbalanced to unbalanced. A 1:1 balun is used with dipoles fed by coax.

Feed lines: coax has loss that increases with frequency; ladder line and open-wire feeders have lower loss but require a tuner and balanced antenna.

Antenna types: half-wave dipole (fed at center, about 73 ohms), quarter-wave vertical with ground plane, Yagi-Uda (directional, gain from parasitic elements), and loop antennas.

Polarization: horizontal for dipoles and Yagis, vertical for most mobile and repeater antennas. Cross-polarization causes significant signal loss.

FM deviation: narrowband FM uses ±5 kHz deviation on 2 m and 70 cm; wideband FM is used for broadcast. CTCSS tones are subaudible tones used to access repeaters.

Digital modes: FT8 (15-second cycles, weak-signal), PSK31 (narrowband keyboard-to-keyboard), RTTY (frequency-shift keying), and packet radio (AX.25). They require audio interface and PTT control.

Power and safety: RF exposure limits are frequency-dependent (MPE limits in FCC OET Bulletin 65); avoid contact with antennas, use proper grounding, and never transmit into an antenna with high SWR without checking the match.

Part 97 defines the Amateur Radio Service as a voluntary, noncommercial service of self-training, intercommunication, and technical investigation, with no pecuniary interest and no broadcasting.

The FCC issues three license classes: Technician, General, and Amateur Extra. Each license term is 10 years and may be renewed within the 90-day window before expiration; a two-year grace period follows expiration, but operation is not permitted until renewal is granted.

Technician privileges include all amateur bands above 30 MHz, plus limited HF access: CW on 80, 40, and 15 m, and data on 80, 40, and 15 m, all within the Novice-class subbands; power is limited to 1500 W PEP output.

Control operator types are local, remote, and automatic (repeater or auxiliary station). The control operator is responsible for the proper operation of the station, and the station must have a control point.

Identification: transmit your FCC-assigned call sign at the beginning and end of each communication and at least every 10 minutes during it; use phone (voice), CW, or digital identification, and identify with the call sign of the station you are operating.

Third-party communications are messages sent between two amateur stations on behalf of a third party; they are permitted only when the third party's country has a third-party agreement with the US, and never for business or pecuniary interest.

Prohibited transmissions include obscene or indecent language, music (except incidental to an authorized retransmission), commercial advertising, and communications for hire or material compensation; business use is generally prohibited.

The FCC may inspect your station and records upon request. You must keep a copy of your license (or FCC ULS record) available, and repeater or auxiliary stations must maintain records of control-point location and control operator.

Frequency coordination is voluntary for repeaters; the FCC does not assign repeater frequencies, but the recognized frequency coordinator's recommendation is generally followed to minimize interference.

Use the phonetic alphabet (Alfa, Bravo, Charlie, Delta, Echo, Foxtrot, Golf, Hotel, India, Juliett, Kilo, Lima, Mike, November, Oscar, Papa, Quebec, Romeo, Sierra, Tango, Uniform, Victor, Whiskey, X-ray, Yankee, Zulu) to spell call signs and unfamiliar words.

Calling procedure: listen first, then call the other station with its call sign followed by your own; use "CQ" to call any station, and respond with the calling station's call sign followed by yours.

RST system: R (readability 1-5), S (signal strength 1-9), T (tone 1-9, used for CW). Phone reports usually give R and S; CW reports include T.

Repeater operation: offset (standard 600 kHz on 2 m, 5 MHz on 70 cm), CTCSS tone or DCS code to access the repeater, and the courtesy tone indicates the repeater is ready for the next transmission.

Emergency traffic: use "MAYDAY" (from French m'aidez) on voice and "SOS" on CW; emergency communications may be transmitted on any frequency, and the FCC permits operation outside normal privileges during a bona fide emergency.

Net control stations direct net traffic; check in with your call sign, follow the net control's instructions, and use tactical call signs only if the net permits them.

Q signals: QRM (man-made interference), QRN (atmospheric noise), QSB (fading), QSL (acknowledgment), QSY (change frequency), QTH (location), QRT (stop transmitting).

Station control: the control operator must be able to disable the transmitter remotely; automatic control is allowed for repeaters, auxiliary stations, and certain digital stations, but the control operator remains responsible.

Logging is not required for most amateur operation, but keeping a log is useful for awards (DXCC, WAS) and for resolving interference complaints; some digital modes and contests require it.

Ohm's Law: V = I × R, I = V / R, R = V / I. Power: P = V × I = I²R = V²/R. These apply to DC circuits and to resistive AC circuits.

Series resistance: R_total = R1 + R2 + ...; parallel resistance: 1/R_total = 1/R1 + 1/R2 + ...; for two resistors, R_total = (R1 × R2) / (R1 + R2).

Capacitive reactance Xc = 1 / (2πfC); inductive reactance Xl = 2πfL. Reactance increases with frequency for capacitors and decreases for inductors.

Resonance occurs when Xl = Xc, giving f = 1 / (2π√(LC)). At resonance, a series circuit has minimum impedance and a parallel circuit has maximum impedance.

Decibels: dB = 10 log10(P2/P1) for power; dB = 20 log10(V2/V1) for voltage. A 3 dB increase doubles power; a 10 dB increase multiplies power by 10.

Wavelength: λ (meters) = 300 / f (MHz). A half-wave dipole is about 468 / f (MHz) feet long; a quarter-wave vertical is about 234 / f (MHz) feet.

Frequency bands: HF 3-30 MHz, VHF 30-300 MHz, UHF 300-3000 MHz. The 2 m band is 144-148 MHz; the 70 cm band is 420-450 MHz.

Modulation: AM varies amplitude, FM varies frequency, SSB is amplitude modulation with one sideband and suppressed carrier, and CW is on-off keying of a carrier.

The ionosphere (D, E, F1, F2 layers) refracts HF signals; the F2 layer supports long-distance skip, and the D layer absorbs lower HF signals during daylight.

Transceiver: a combined transmitter and receiver. A transverter converts one band to another; a linear amplifier increases power and must be rated for the mode used (SSB, CW, FM).

SWR (standing wave ratio) measures impedance match; 1:1 is ideal, below 2:1 is generally acceptable, and above 3:1 may cause transmitter protection to reduce power. Use an SWR meter or antenna analyzer.

Balun (balanced-to-unbalanced) matches a balanced antenna to an unbalanced feed line; an unun matches unbalanced to unbalanced. A 1:1 balun is used with dipoles fed by coax.

Feed lines: coax has loss that increases with frequency; ladder line and open-wire feeders have lower loss but require a tuner and balanced antenna.

Antenna types: half-wave dipole (fed at center, about 73 ohms), quarter-wave vertical with ground plane, Yagi-Uda (directional, gain from parasitic elements), and loop antennas.

Polarization: horizontal for dipoles and Yagis, vertical for most mobile and repeater antennas. Cross-polarization causes significant signal loss.

FM deviation: narrowband FM uses ±5 kHz deviation on 2 m and 70 cm; wideband FM is used for broadcast. CTCSS tones are subaudible tones used to access repeaters.

Digital modes: FT8 (15-second cycles, weak-signal), PSK31 (narrowband keyboard-to-keyboard), RTTY (frequency-shift keying), and packet radio (AX.25). They require audio interface and PTT control.

Power and safety: RF exposure limits are frequency-dependent (MPE limits in FCC OET Bulletin 65); avoid contact with antennas, use proper grounding, and never transmit into an antenna with high SWR without checking the match.

Part 97 defines the Amateur Radio Service as a voluntary, noncommercial service of self-training, intercommunication, and technical investigation, with no pecuniary interest and no broadcasting.

The FCC issues three license classes: Technician, General, and Amateur Extra. Each license term is 10 years and may be renewed within the 90-day window before expiration; a two-year grace period follows expiration, but operation is not permitted until renewal is granted.

Technician privileges include all amateur bands above 30 MHz, plus limited HF access: CW on 80, 40, and 15 m, and data on 80, 40, and 15 m, all within the Novice-class subbands; power is limited to 1500 W PEP output.

Control operator types are local, remote, and automatic (repeater or auxiliary station). The control operator is responsible for the proper operation of the station, and the station must have a control point.

Identification: transmit your FCC-assigned call sign at the beginning and end of each communication and at least every 10 minutes during it; use phone (voice), CW, or digital identification, and identify with the call sign of the station you are operating.

Third-party communications are messages sent between two amateur stations on behalf of a third party; they are permitted only when the third party's country has a third-party agreement with the US, and never for business or pecuniary interest.

Prohibited transmissions include obscene or indecent language, music (except incidental to an authorized retransmission), commercial advertising, and communications for hire or material compensation; business use is generally prohibited.

The FCC may inspect your station and records upon request. You must keep a copy of your license (or FCC ULS record) available, and repeater or auxiliary stations must maintain records of control-point location and control operator.

Frequency coordination is voluntary for repeaters; the FCC does not assign repeater frequencies, but the recognized frequency coordinator's recommendation is generally followed to minimize interference.

Use the phonetic alphabet (Alfa, Bravo, Charlie, Delta, Echo, Foxtrot, Golf, Hotel, India, Juliett, Kilo, Lima, Mike, November, Oscar, Papa, Quebec, Romeo, Sierra, Tango, Uniform, Victor, Whiskey, X-ray, Yankee, Zulu) to spell call signs and unfamiliar words.

Calling procedure: listen first, then call the other station with its call sign followed by your own; use "CQ" to call any station, and respond with the calling station's call sign followed by yours.

RST system: R (readability 1-5), S (signal strength 1-9), T (tone 1-9, used for CW). Phone reports usually give R and S; CW reports include T.

Repeater operation: offset (standard 600 kHz on 2 m, 5 MHz on 70 cm), CTCSS tone or DCS code to access the repeater, and the courtesy tone indicates the repeater is ready for the next transmission.

Emergency traffic: use "MAYDAY" (from French m'aidez) on voice and "SOS" on CW; emergency communications may be transmitted on any frequency, and the FCC permits operation outside normal privileges during a bona fide emergency.

Net control stations direct net traffic; check in with your call sign, follow the net control's instructions, and use tactical call signs only if the net permits them.

Q signals: QRM (man-made interference), QRN (atmospheric noise), QSB (fading), QSL (acknowledgment), QSY (change frequency), QTH (location), QRT (stop transmitting).

Station control: the control operator must be able to disable the transmitter remotely; automatic control is allowed for repeaters, auxiliary stations, and certain digital stations, but the control operator remains responsible.

Logging is not required for most amateur operation, but keeping a log is useful for awards (DXCC, WAS) and for resolving interference complaints; some digital modes and contests require it.

Ohm's Law: V = I × R, I = V / R, R = V / I. Power: P = V × I = I²R = V²/R. These apply to DC circuits and to resistive AC circuits.

Series resistance: R_total = R1 + R2 + ...; parallel resistance: 1/R_total = 1/R1 + 1/R2 + ...; for two resistors, R_total = (R1 × R2) / (R1 + R2).

Capacitive reactance Xc = 1 / (2πfC); inductive reactance Xl = 2πfL. Reactance increases with frequency for capacitors and decreases for inductors.

Resonance occurs when Xl = Xc, giving f = 1 / (2π√(LC)). At resonance, a series circuit has minimum impedance and a parallel circuit has maximum impedance.

Decibels: dB = 10 log10(P2/P1) for power; dB = 20 log10(V2/V1) for voltage. A 3 dB increase doubles power; a 10 dB increase multiplies power by 10.

Wavelength: λ (meters) = 300 / f (MHz). A half-wave dipole is about 468 / f (MHz) feet long; a quarter-wave vertical is about 234 / f (MHz) feet.

Frequency bands: HF 3-30 MHz, VHF 30-300 MHz, UHF 300-3000 MHz. The 2 m band is 144-148 MHz; the 70 cm band is 420-450 MHz.

Modulation: AM varies amplitude, FM varies frequency, SSB is amplitude modulation with one sideband and suppressed carrier, and CW is on-off keying of a carrier.

The ionosphere (D, E, F1, F2 layers) refracts HF signals; the F2 layer supports long-distance skip, and the D layer absorbs lower HF signals during daylight.

Transceiver: a combined transmitter and receiver. A transverter converts one band to another; a linear amplifier increases power and must be rated for the mode used (SSB, CW, FM).

SWR (standing wave ratio) measures impedance match; 1:1 is ideal, below 2:1 is generally acceptable, and above 3:1 may cause transmitter protection to reduce power. Use an SWR meter or antenna analyzer.

Balun (balanced-to-unbalanced) matches a balanced antenna to an unbalanced feed line; an unun matches unbalanced to unbalanced. A 1:1 balun is used with dipoles fed by coax.

Feed lines: coax has loss that increases with frequency; ladder line and open-wire feeders have lower loss but require a tuner and balanced antenna.

Antenna types: half-wave dipole (fed at center, about 73 ohms), quarter-wave vertical with ground plane, Yagi-Uda (directional, gain from parasitic elements), and loop antennas.

Polarization: horizontal for dipoles and Yagis, vertical for most mobile and repeater antennas. Cross-polarization causes significant signal loss.

FM deviation: narrowband FM uses ±5 kHz deviation on 2 m and 70 cm; wideband FM is used for broadcast. CTCSS tones are subaudible tones used to access repeaters.

Digital modes: FT8 (15-second cycles, weak-signal), PSK31 (narrowband keyboard-to-keyboard), RTTY (frequency-shift keying), and packet radio (AX.25). They require audio interface and PTT control.

Power and safety: RF exposure limits are frequency-dependent (MPE limits in FCC OET Bulletin 65); avoid contact with antennas, use proper grounding, and never transmit into an antenna with high SWR without checking the match.

Part 97 defines the Amateur Radio Service as a voluntary, noncommercial service of self-training, intercommunication, and technical investigation, with no pecuniary interest and no broadcasting.

The FCC issues three license classes: Technician, General, and Amateur Extra. Each license term is 10 years and may be renewed within the 90-day window before expiration; a two-year grace period follows expiration, but operation is not permitted until renewal is granted.

Technician privileges include all amateur bands above 30 MHz, plus limited HF access: CW on 80, 40, and 15 m, and data on 80, 40, and 15 m, all within the Novice-class subbands; power is limited to 1500 W PEP output.

Control operator types are local, remote, and automatic (repeater or auxiliary station). The control operator is responsible for the proper operation of the station, and the station must have a control point.

Identification: transmit your FCC-assigned call sign at the beginning and end of each communication and at least every 10 minutes during it; use phone (voice), CW, or digital identification, and identify with the call sign of the station you are operating.

Third-party communications are messages sent between two amateur stations on behalf of a third party; they are permitted only when the third party's country has a third-party agreement with the US, and never for business or pecuniary interest.

Prohibited transmissions include obscene or indecent language, music (except incidental to an authorized retransmission), commercial advertising, and communications for hire or material compensation; business use is generally prohibited.

The FCC may inspect your station and records upon request. You must keep a copy of your license (or FCC ULS record) available, and repeater or auxiliary stations must maintain records of control-point location and control operator.

Frequency coordination is voluntary for repeaters; the FCC does not assign repeater frequencies, but the recognized frequency coordinator's recommendation is generally followed to minimize interference.

Use the phonetic alphabet (Alfa, Bravo, Charlie, Delta, Echo, Foxtrot, Golf, Hotel, India, Juliett, Kilo, Lima, Mike, November, Oscar, Papa, Quebec, Romeo, Sierra, Tango, Uniform, Victor, Whiskey, X-ray, Yankee, Zulu) to spell call signs and unfamiliar words.

Calling procedure: listen first, then call the other station with its call sign followed by your own; use "CQ" to call any station, and respond with the calling station's call sign followed by yours.

RST system: R (readability 1-5), S (signal strength 1-9), T (tone 1-9, used for CW). Phone reports usually give R and S; CW reports include T.

Repeater operation: offset (standard 600 kHz on 2 m, 5 MHz on 70 cm), CTCSS tone or DCS code to access the repeater, and the courtesy tone indicates the repeater is ready for the next transmission.

Emergency traffic: use "MAYDAY" (from French m'aidez) on voice and "SOS" on CW; emergency communications may be transmitted on any frequency, and the FCC permits operation outside normal privileges during a bona fide emergency.

Net control stations direct net traffic; check in with your call sign, follow the net control's instructions, and use tactical call signs only if the net permits them.

Q signals: QRM (man-made interference), QRN (atmospheric noise), QSB (fading), QSL (acknowledgment), QSY (change frequency), QTH (location), QRT (stop transmitting).

Station control: the control operator must be able to disable the transmitter remotely; automatic control is allowed for repeaters, auxiliary stations, and certain digital stations, but the control operator remains responsible.

Logging is not required for most amateur operation, but keeping a log is useful for awards (DXCC, WAS) and for resolving interference complaints; some digital modes and contests require it.

Ohm's Law: V = I × R, I = V / R, R = V / I. Power: P = V × I = I²R = V²/R. These apply to DC circuits and to resistive AC circuits.

Series resistance: R_total = R1 + R2 + ...; parallel resistance: 1/R_total = 1/R1 + 1/R2 + ...; for two resistors, R_total = (R1 × R2) / (R1 + R2).

Capacitive reactance Xc = 1 / (2πfC); inductive reactance Xl = 2πfL. Reactance increases with frequency for capacitors and decreases for inductors.

Resonance occurs when Xl = Xc, giving f = 1 / (2π√(LC)). At resonance, a series circuit has minimum impedance and a parallel circuit has maximum impedance.

Decibels: dB = 10 log10(P2/P1) for power; dB = 20 log10(V2/V1) for voltage. A 3 dB increase doubles power; a 10 dB increase multiplies power by 10.

Wavelength: λ (meters) = 300 / f (MHz). A half-wave dipole is about 468 / f (MHz) feet long; a quarter-wave vertical is about 234 / f (MHz) feet.

Frequency bands: HF 3-30 MHz, VHF 30-300 MHz, UHF 300-3000 MHz. The 2 m band is 144-148 MHz; the 70 cm band is 420-450 MHz.

Modulation: AM varies amplitude, FM varies frequency, SSB is amplitude modulation with one sideband and suppressed carrier, and CW is on-off keying of a carrier.

The ionosphere (D, E, F1, F2 layers) refracts HF signals; the F2 layer supports long-distance skip, and the D layer absorbs lower HF signals during daylight.

Transceiver: a combined transmitter and receiver. A transverter converts one band to another; a linear amplifier increases power and must be rated for the mode used (SSB, CW, FM).

SWR (standing wave ratio) measures impedance match; 1:1 is ideal, below 2:1 is generally acceptable, and above 3:1 may cause transmitter protection to reduce power. Use an SWR meter or antenna analyzer.

Balun (balanced-to-unbalanced) matches a balanced antenna to an unbalanced feed line; an unun matches unbalanced to unbalanced. A 1:1 balun is used with dipoles fed by coax.

Feed lines: coax has loss that increases with frequency; ladder line and open-wire feeders have lower loss but require a tuner and balanced antenna.

Antenna types: half-wave dipole (fed at center, about 73 ohms), quarter-wave vertical with ground plane, Yagi-Uda (directional, gain from parasitic elements), and loop antennas.

Polarization: horizontal for dipoles and Yagis, vertical for most mobile and repeater antennas. Cross-polarization causes significant signal loss.

FM deviation: narrowband FM uses ±5 kHz deviation on 2 m and 70 cm; wideband FM is used for broadcast. CTCSS tones are subaudible tones used to access repeaters.

Digital modes: FT8 (15-second cycles, weak-signal), PSK31 (narrowband keyboard-to-keyboard), RTTY (frequency-shift keying), and packet radio (AX.25). They require audio interface and PTT control.

Power and safety: RF exposure limits are frequency-dependent (MPE limits in FCC OET Bulletin 65); avoid contact with antennas, use proper grounding, and never transmit into an antenna with high SWR without checking the match.