Amateur Radio Glossary

Traditional radio transmission where audio is carried as a continuous signal. FM voice on VHF/UHF repeaters is analogue. Contrasted with digital modes like DMR.

A device used to transmit or receive radio signals. Ranges from a simple wire dipole to a complex beam antenna. One of the most important parts of any station. See the antenna calculators for element length calculations.

Automatic Packet Reporting System. A digital system used for GPS position reporting, short messaging and telemetry over amateur radio.

A range of radio frequencies allocated for a specific use. Common amateur bands include 2m (144–146 MHz), 70cm (430–440 MHz), and HF bands from 1.8 MHz upwards.

A fixed radio setup operated from home or a permanent location, as opposed to a mobile or portable setup.

One of the two main DMR networks used in the UK. Widely used for personal hotspots. More at brandmeister.network. See also: DMR guide.

Your unique amateur radio identification, issued with your licence by Ofcom. UK callsigns follow patterns like M7ABC (Foundation), 2E0ABC (Intermediate), and G0ABC (Full).

A configuration file for a DMR radio. Contains channels, frequencies, talkgroups, colour codes, and your DMR ID. See the DMR guide for more.

Cable used to connect a radio to an antenna. Has a centre conductor surrounded by insulation and a braided outer shield. Common types include RG-58, RG-213 and LMR-400.

A number (0–15) used by DMR repeaters as a filter — similar to CTCSS on FM. Your radio must be set to the matching colour code to access a DMR repeater. GB7AL uses CC2, GB7MK uses CC13.

A general call meaning "calling anyone". Used on HF and occasionally on VHF/UHF to invite a response from any listening station.

Continuous Tone-Coded Squelch System. A sub-audible tone transmitted along with your voice that opens the squelch on FM repeaters. Most Suffolk FM repeaters use 110.9 Hz. Must be set correctly or the repeater won't respond.

Digital Mobile Radio. A digital voice mode widely used on amateur radio. Offers cleaner audio than FM and connects to worldwide networks via linked repeaters. See the DMR guide.

A unique numeric identifier linked to your callsign. Required to use DMR repeaters and networks. Register free at radioid.net.

Digital Smart Technology for Amateur Radio. A digital voice and data mode developed by Icom. Used on the local REF079C net — see the nets page.

Using separate transmit and receive frequencies. All repeaters work in duplex — you transmit on the input frequency and receive on the output.

Frequency Modulation. The most common analogue voice mode on VHF and UHF. All the FM repeaters listed on the repeaters page use FM voice.

The entry-level UK amateur radio licence. M7 prefix callsign, up to 25 watts. Enough to use all local Suffolk repeaters. See the getting started guide.

The highest UK amateur radio licence. G prefix callsign, up to 1000 watts, all bands, worldwide operating privileges.

A measure of how effectively an antenna focuses radio energy in a particular direction, compared to a reference antenna. Higher gain in one direction means less coverage in others. Use the ERP/EIRP calculator to see how gain affects your effective radiated power.

A small personal device that connects a radio to DMR (or other digital mode) networks over broadband. Lets you use DMR from home without a local repeater. See the DMR guide.

Handheld Transceiver. A portable battery-powered radio — the most common starting point for new amateurs. See the equipment guide.

Long Range radio technology. Uses spread-spectrum modulation to achieve long range at low power. Used by MeshCore and Meshtastic for mesh networking.

An open-source encrypted mesh messaging system running on LoRa hardware. No internet or phone signal required. Local community at ipnt.uk. See the MeshCore page.

A radio designed for use in a vehicle or as a compact home station. Higher power and better performance than a handheld.

A scheduled on-air meeting between amateur radio operators. Nets typically run at a fixed time on a set frequency or repeater, with a net control station managing who speaks. A great way to practise operating, make contacts, and meet other local amateurs. See the local nets page for what's active in Suffolk.

The difference between a repeater's transmit (input) and receive (output) frequencies. Standard offsets are –600 kHz on 2m and –7.6 MHz on 70cm in the UK.

A licensed person using amateur radio equipment. You must hold a valid licence to transmit.

One of the two main DMR networks in the UK. Used by the local SARG repeaters GB7AL and GB7MK.

How radio signals travel through the atmosphere. On VHF/UHF, signals are mostly line-of-sight. On HF bands, signals can bounce off the ionosphere to reach enormous distances.

A radio contact or conversation between operators. "I had a QSO with G0ABC on the repeater" means you had a radio conversation with them.

Your location. "My QTH is Ipswich" means you're operating from Ipswich. Operators often exchange their Maidenhead locator alongside their QTH — use the QTH Locator tool to find yours.

"Who is calling?" Also the name of the popular amateur radio callsign lookup website at qrz.com.

Radio Amateurs' Emergency Network. Volunteers who provide radio communication support during emergencies and public events in the UK.

A radio system that receives your signal and retransmits it from a high site to extend coverage. You transmit on the input frequency and listen on the output. See the repeaters page for all local repeaters.

Radio Frequency. A general term for the radio signals used in amateur radio and other wireless communication.

The informal term for an amateur radio operating space — whether that's a dedicated room, a corner of a bedroom, or the kitchen table.

Direct radio communication between two stations without using a repeater. Both stations use the same frequency. Range is limited by line of sight between the two radios.

Standing Wave Ratio. A measure of how well your antenna is matched to your radio and coax. A high SWR means energy is being reflected back into the radio — not ideal. Aim for 1.5:1 or better.

A virtual channel or group used on DMR networks. TG9 is typically local, TG235 is UK-wide, TG91 is worldwide. You select which talkgroup to monitor on your DMR radio. See DMR guide.

DMR splits a single frequency into two time slots (TS1 and TS2), allowing two simultaneous conversations. Different talkgroups are typically assigned to different timeslots.

Ultra High Frequency. Generally refers to the 70cm amateur band (430–440 MHz). Shorter range than VHF but better building penetration in some situations.

Variable Frequency Oscillator. A radio mode that lets you tune directly to any frequency, as opposed to stepping through pre-programmed memory channels.

Very High Frequency. Generally refers to the 2m amateur band (144–146 MHz). The most commonly used band for local FM voice in the UK.