getontheairGlossary
Short, plain definitions of the words you will hear on the air, at club meetings and in this guide. Where a chapter goes deeper, the term links to it. Terms are grouped by topic; use your browser's find (Ctrl+F / ⌘F) to jump to a word.
Glossary v1.0 · written 2026-10-08 · definitions are general; the rule citations point to 47 CFR Part 97 on eCFR
Licensing and rules
| Term | Meaning |
|---|---|
| Amateur radio service | The FCC radio service for noncommercial, self-training, experimental and public-service communication by licensed individuals (§97.1). "Ham radio" is the everyday name. |
| Part 97 | The section of FCC rules (47 CFR Part 97) that governs US amateur radio. |
| Technician / General / Amateur Extra | The three US license classes available today, each needing a written exam (Elements 2, 3 and 4). See What is ham radio? |
| Element | One written exam. Element 2 = Technician, 3 = General, 4 = Amateur Extra. |
| Question pool | The public set of questions each exam is drawn from; pools are replaced on a fixed schedule. Practice in Ticket to Talk. |
| VE / VEC | Volunteer Examiner — a licensed ham who gives exams. Volunteer Examiner Coordinator — the organization that accredits VEs and files results with the FCC. |
| CSCE | Certificate of Successful Completion of Examination — the paper you get for passing an element; good for exam credit for 365 days. |
| FRN / CORES | FCC Registration Number, obtained in the FCC's CORES system. You need one before your exam. |
| ULS | The FCC's Universal Licensing System, where licenses and call signs are recorded and publicly searchable. |
| Call sign | Your station's identifier, assigned by the FCC (e.g., a prefix such as K, N, W or A, a digit, and a suffix). See What a license costs. |
| Sequential call sign | The call assigned automatically from the next available in line. |
| Vanity call sign | A specific available call sign you request (FCC fee applies). |
| Grace period | The 2 years after a license expires during which it can still be renewed, but you may not transmit. |
| Control operator | The licensed person responsible for a station's transmissions at a given moment. |
| Third-party communications | A message on behalf of someone who is not the control operator — including an unlicensed person speaking under supervision (§97.115). |
| Third-party agreement | A treaty arrangement letting US stations pass third-party messages to a given country. |
| Station identification (ID) | Giving your call sign at least every 10 minutes and at the end of a contact (§97.119). |
| Band plan | Voluntary agreements on what modes go where within a band, on top of the legal rules. |
| PEP | Peak envelope power — the measure FCC power limits use for transmitter output. |
| RF exposure | The requirement that stations keep people below FCC radio-frequency exposure limits (§97.13). |
On the air
| Term | Meaning |
|---|---|
| QSO | A contact — a two-way exchange between stations. |
| CQ | A general call meaning "calling any station." |
| 73 | "Best regards" — a common sign-off (already plural, so no "s" needed). |
| DX | Distant stations, usually in other countries; "working DX." |
| QTH | Location. "My QTH is Lancaster." |
| QRZ? | "Who is calling me?" Also the name of a popular call sign lookup site. |
| QSL | "I confirm receipt." A QSL card (or electronic QSL) confirms a contact. |
| QRP / QRO | Low power (often 5 W or less) / high power. |
| QRM / QRN | Interference from other stations / natural noise such as static. |
| QSY | Change frequency. |
| QRT | Stop transmitting; going off the air. |
| Q signals | Three-letter codes starting with Q, from Morse practice, used as shorthand. |
| Signal report / RST | Readability, Strength and (for CW) Tone — e.g., "59" on voice. |
| Phonetic alphabet | Standard words for letters (Alpha, Bravo, Charlie…) to make call signs clear. |
| Simplex | Talking directly radio-to-radio on one frequency. |
| Repeater | A station, usually on a high site, that receives on one frequency and retransmits on another to extend range. |
| Offset / split | The difference between a repeater's input and output frequencies. |
| CTCSS / PL tone | A sub-audible tone some repeaters require before they will retransmit. |
| Net / net control | A scheduled on-air meeting / the station running it. See First net. |
| Check-in | Announcing yourself to a net. |
| Pileup | Many stations calling one station at once. See Pileups. |
| Split operation | A busy station listening on a different frequency than it transmits. |
| Elmer | A mentor. See Clubs and Elmers. |
| Log / logbook | Your record of contacts (date, UTC time, frequency, mode, call). See Logging. |
| UTC / Zulu | Coordinated Universal Time, the standard for logs. "1800Z" = 18:00 UTC. |
| ADIF | The standard file format for exchanging logs between programs. |
| Cabrillo | The standard file format for submitting contest logs. |
Modes
| Term | Meaning |
|---|---|
| Mode | How information is carried: voice, Morse, data, image. |
| FM | Frequency modulation — standard for VHF/UHF voice and repeaters. |
| SSB (USB/LSB) | Single sideband — efficient voice mode for HF; upper or lower sideband. |
| AM | Amplitude modulation — older voice mode, still enjoyed by some. |
| CW | Continuous wave — Morse code. See CW. |
| Digital modes | Text or data sent by computer and radio: FT8, FT4, RTTY, PSK31, packet and more. |
| FT8 / FT4 | Weak-signal digital modes with short fixed exchanges, run in programs like WSJT-X. |
| RTTY | Radioteletype — an older, still-popular keyboard digital mode. |
| Packet / APRS | Packet radio sends data in addressed bursts; APRS uses it for positions, messages and telemetry. |
| SSTV | Slow-scan television — still images over a voice channel. See SSTV. |
| Winlink | Email over radio, widely used for emergency messaging. |
| DMR / D-STAR / System Fusion | Digital voice systems common on VHF/UHF repeaters. |
Equipment and antennas
| Term | Meaning |
|---|---|
| HT | Handheld transceiver — a walkie-talkie-style ham radio. |
| Transceiver | A radio that both transmits and receives. |
| Mobile / base | A radio for a vehicle / for a fixed station. |
| SDR | Software-defined radio — much of the signal processing done in software. See SDR. |
| Feed line / coax | The cable from radio to antenna; coaxial cable is most common. |
| SWR | Standing wave ratio — how well the antenna system is matched to the radio. 1:1 is perfect; lower is better. |
| Antenna tuner (ATU) | A device that matches the radio to an antenna system that is not resonant. |
| Dipole | A basic antenna of two equal wires fed in the middle. |
| EFHW | End-fed half-wave antenna — popular for portable work. See EFHW. |
| Vertical | An antenna with a vertical radiator, usually with radials. See Verticals. |
| Yagi | A directional beam antenna with multiple elements. |
| Radials / counterpoise | Wires that form the "other half" of a vertical or end-fed antenna system. |
| Balun / unun | Transformers that connect balanced or unbalanced antennas to coax. |
| Choke | A device that keeps RF current off the outside of the coax. |
| Ground (station / safety) | Bonding and grounding for electrical safety and lightning protection; not the same as an RF counterpoise. |
| Dummy load | A resistor that absorbs transmitter power so you can test without radiating. |
| CAT | Computer control of a radio over a cable. |
| Digirig / sound-card interface | Hardware connecting radio audio to a computer for digital modes. |
Bands and propagation
| Term | Meaning |
|---|---|
| Band | A range of frequencies, often named by wavelength: 2 m, 70 cm, 20 m. |
| HF / VHF / UHF | 3–30 MHz / 30–300 MHz / 300–3,000 MHz. |
| Propagation | How radio signals travel between stations. See Technician HF & propagation. |
| Ionosphere | Ionized upper-atmosphere layers that can bend HF signals back to Earth. |
| Skip / sky wave | A signal returned by the ionosphere, landing far away. |
| Ground wave / line of sight | Short-range paths along the ground / direct visual-range paths typical of VHF/UHF. |
| MUF | Maximum usable frequency for a given path at a given time. |
| Solar cycle | The roughly 11-year rise and fall of solar activity that drives HF conditions. |
| SFI / K index / A index | Solar flux (higher helps upper HF) / short-term and daily geomagnetic disturbance (lower is better). |
| Sporadic E | Patchy, intense ionization that can briefly open 10 m, 6 m and 2 m over 500–1,500 miles. |
| Gray line | The twilight band around the Earth, often good for long paths. |
| Tropospheric ducting | Weather-driven VHF/UHF propagation over hundreds of miles. |
Satellites and space
| Term | Meaning |
|---|---|
| AOS / LOS | Acquisition of signal (satellite rises) / loss of signal (it sets). |
| Pass | One trip of a satellite across your sky. |
| Doppler shift | Frequency change caused by the satellite's motion; you retune during the pass. |
| Uplink / downlink | The frequency you transmit on / the one you listen on. |
| FM bird / linear transponder | A satellite acting like a single-channel FM repeater / one that relays a slice of spectrum (SSB, CW). |
| TLE / Keplerian elements | Orbit data that tracking apps use to predict passes. |
| ARISS | Amateur Radio on the International Space Station. See Satellites. |
| AMSAT | Organizations that build and support amateur satellites. |
Events, awards and programs
| Term | Meaning |
|---|---|
| Contest | A timed on-air event to make as many contacts as possible. See Contesting. |
| Exchange | The specific information sent in a contest contact (e.g., class and section on Field Day). |
| Field Day | The annual June operating event focused on portable and emergency-capable stations. See Field Day. |
| GOTA station | "Get On The Air" — a Field Day station for new and unlicensed operators. |
| QSO party | A contest centered on one state, province or region. |
| Special event station | A station operating for a celebration or anniversary, often with a short call sign. |
| POTA / SOTA / WWFF | Parks on the Air / Summits on the Air / World Wide Flora and Fauna — programs for operating from parks and summits. See Programs. |
| Activator / hunter (chaser) | The station at the park or summit / the station contacting them. |
| Park-to-park (P2P) | A contact between two activators. |
| Spot / spotting | Posting a station's frequency so others can find it. |
| DXCC / WAS | Popular awards for confirming contacts with many countries / all 50 US states. |
| JOTA | Jamboree on the Air — the October worldwide Scouting radio event. See Scouting & ham radio. |
Emergency and public service
| Term | Meaning |
|---|---|
| Emcomm | Emergency communications. See Emergency communications. |
| ARES | Amateur Radio Emergency Service — ARRL's volunteer emergency program. |
| RACES | Radio Amateur Civil Emergency Service — amateur operation for a government emergency-management agency (§97.407). |
| AUXCOMM | Auxiliary emergency communications volunteers working within incident command. |
| ICS / ICS-213 | Incident Command System / its standard general message form. |
| NTS / radiogram | National Traffic System / its formal message format. |
| Tactical call | A function name ("Aid 3", "Net Control") used alongside legal IDs during events. |
| Go-kit | A ready-packed radio kit for deployments. |
| SKYWARN | The National Weather Service storm-spotter program — no license required. See SKYWARN. |
Related
v1.0, 2026-10-08. Spotted an error or a missing term? Comment or propose an edit.
Notes & edits
Comments and proposed markdown sit in a queue. Nothing is public until it is reviewed. How this works.