Reference · Offline
Radio Glossary
69 plain-language terms for ham radio, GMRS, digital modes, and emcomm — search below or browse A–Z.
- Access tone
- Sub-audible tone (CTCSS or DCS) your radio transmits so a repeater opens only for stations using the correct code.
- APRS
- Automatic Packet Reporting System — ham digital mode for position reports, weather, and short messages, often on 144.390 MHz.
- ARES
- Amateur Radio Emergency Service — ARRL-sponsored volunteer emcomm program that coordinates with served agencies during disasters and exercises.
- ARRL
- American Radio Relay League — national ham radio organization; publishes band plans, runs VE exam programs, and supports ARES.
- Band plan
- Gentlemen's agreement on how ham bands are divided by mode (CW, phone, digital). Not FCC law, but good practice.
- Baofeng
- Popular low-cost dual-band handheld brand (UV-5R class). Useful for learning — program carefully and verify Part 97/95 rules.
- BrandMeister
- Worldwide DMR network. East TN repeaters like KE4CCB and KM4KT often connect here for statewide talkgroups.
- Check-in
- Announcing your presence on a net so net control can log you. Listen first, then follow the net script.
- CHIRP
- Free open-source programming software for many VHF/UHF radios. Import CSV frequency lists and clone channel memories.
- Color Code
- DMR digital equivalent of a tone — must match the repeater (often CC 1). Wrong code = no audio.
- COML
- Communications Unit Leader — ICS role that plans radio assignments, ICS-205, and frequency coordination on incidents.
- CSQ
- Carrier squelch — repeater opens on signal strength alone with no tone required.
- CTCSS
- Continuous Tone-Coded Squelch System — sub-audible tone (Hz) that opens many FM repeaters. Same idea as PL.
- CW
- Continuous wave — Morse code telegraphy. Still used on HF and for weak-signal work.
- D-Star
- Icom digital voice mode using reflectors and repeater linking. Separate from DMR.
- DCS
- Digital Coded Squelch — digital access code alternative to CTCSS on some repeaters.
- DMR
- Digital Mobile Radio — time-slot digital voice with color codes and talkgroups on networks like BrandMeister.
- Duplex
- Operating through a repeater — you transmit on one frequency and listen on another (split).
- EC
- Emergency Coordinator — ARES leader for a section or county who coordinates volunteer emcomm response.
- EchoLink
- Internet-linked ham system connecting repeaters and nodes worldwide via software or radio.
- ERP
- Effective radiated power — transmitter power plus antenna gain minus feedline loss. What the FCC limits reference.
- Extra
- Highest US amateur license class — full HF privileges and all VHF/UHF bands.
- FCC
- Federal Communications Commission — sets Part 97 (ham) and Part 95 (GMRS/FRS) rules.
- FRS
- Family Radio Service — license-free UHF walkie-talkies with low power and fixed channels. No repeaters.
- FT8
- Weak-signal digital HF mode — 15-second exchanges, popular on 20m and other bands when propagation is marginal.
- General
- Middle US ham license class — adds most HF phone and digital privileges beyond Technician.
- GMRS
- General Mobile Radio Service — licensed UHF voice service ($35 FCC fee, no exam). Repeaters and higher power than FRS.
- Go-kit
- Packed emcomm bag — radios, power, antennas, forms, and credentials ready for deployment.
- Grid square
- Maidenhead locator — two to six characters encoding latitude/longitude for contests and logging.
- HF
- High frequency — roughly 3–30 MHz; skywave propagation for regional and global contacts.
- HT
- Handheld transceiver — battery-powered portable radio, often dual-band VHF/UHF.
- ICS
- Incident Command System — FEMA/NIMS structure for managing emergencies. Radio planning uses ICS-205 and related forms.
- ICS-205
- Radio Communications Plan — lists assigned frequencies, tones, and users for an operational period.
- ICS-213
- General Message form — standard format for written traffic between ICS positions.
- ICS-214
- Unit Activity Log — chronological record of actions, locations, and messages for your assigned unit.
- Meshtastic
- Open-source LoRa mesh texting — license-free on ISM bands. Good contingency when voice repeaters fail.
- MURS
- Multi-Use Radio Service — five VHF channels, no license. Power and antenna height limits apply.
- NCS
- Net Control Station — operator who directs check-ins, traffic, and net discipline during a scheduled or emergency net.
- Net
- Scheduled on-air meeting — club net, SKYWARN training, ARES check-in, or traffic handling.
- NIMS
- National Incident Management System — federal framework ICS implements. Emcomm volunteers train to these standards.
- NVIS
- Near Vertical Incidence Skywave — HF technique using low dipoles for regional coverage (roughly 300–500 km).
- Offset
- Repeater input vs output difference — typically −600 kHz on 2m and +5 MHz on 70cm in the US.
- Op period
- Operational period — ICS time block (often 12 hours) with defined objectives, assignments, and comms plan.
- PACE
- Primary, Alternate, Contingency, Emergency — four-layer communications plan so one failure does not leave you silent.
- Part 95
- FCC rules for GMRS, FRS, and CB. GMRS license required; FRS is license-free within limits.
- Part 97
- FCC amateur radio rules — licensing, bands, power limits, and prohibited uses.
- Phonetic alphabet
- NATO spelling (Alpha, Bravo, Charlie…) used to clarify callsigns and tactical IDs on noisy channels.
- PL
- Private Line — Motorola trademark name for CTCSS tones. Hams say "PL 123.0" meaning transmit tone 123.0 Hz.
- POTA
- Parks on the Air — portable operating program activating parks worldwide for awards and practice.
- Prowords
- Standard net phrases (Roger, Say again, Over) replacing police 10-codes for clarity on ham emcomm nets.
- QSO
- A completed radio contact — conversation or exchange of signal reports between stations.
- RACES
- Radio Amateur Civil Emergency Service — state/civil-defense emcomm program operating under government authority when activated.
- Repeater
- Station that receives on one frequency and retransmits on another to extend handheld range.
- RST
- Readability-Strength-Tone report — standard signal report format, especially on CW and HF phone.
- Simplex
- Direct radio-to-radio on one frequency — no repeater in the path. National calling: 146.520 MHz (2m).
- SKYWARN
- NWS spotter program — trained volunteers report severe weather via ham, GMRS, phone, or web.
- SOTA
- Summits on the Air — portable operating from mountain summits, similar spirit to POTA.
- SSB
- Single sideband — efficient HF voice mode (USB/LSB) used on most ham phone bands below 50 MHz.
- SWR
- Standing wave ratio — measure of antenna match. High SWR can damage radios; tune or adjust antenna.
- Talkgroup
- DMR routing ID — virtual channel on a network (e.g. Tennessee statewide 3147 on BrandMeister).
- Technician
- Entry US ham license — VHF/UHF privileges plus limited HF. First step for most new operators.
- Time slot
- DMR divides each frequency into two slots (TS1/TS2). Repeater and hotspot must agree on slot.
- Tone encode
- CTCSS or DCS your radio transmits to access a repeater. Must match repeater input requirement.
- Tone squelch
- Receive filter requiring a tone before opening audio — stops hearing other users on the same output frequency.
- UHF
- Ultra high frequency — roughly 300 MHz–3 GHz; 70cm ham band (420–450 MHz) and GMRS.
- ULS
- FCC Universal Licensing System — where you look up ham and GMRS licenses and apply for new ones.
- VE
- Volunteer Examiner — licensed ham who administers FCC exam sessions with other VEs.
- VHF
- Very high frequency — roughly 30–300 MHz; 2m ham band (144–148 MHz) and many repeaters.
- Winlink
- Ham email over radio — RMS gateways on HF/VHF connect to internet when infrastructure is down.
Related tools
Go deeper
CTCSS DecoderTone tables and encode/decode.
Repeater OffsetCalculate input frequency.
Simplex CallingNational calling frequencies.
GMRS ChannelsRepeater pairs and power.
DMR & DigitalTalkgroups and color codes.
PACE PlannerFour-layer comms plan.
CHIRP Cheat SheetProgramming workflow.
NVIS AdvisorRegional HF technique.
FAQ