Radio glossary

44 terms

Allstar

Software that links radio nodes together over the internet.

Antenna gain

How much an antenna focuses signal in one direction, measured in dB.

Band

A range of frequencies set aside for a radio service.

Base station

A radio set up at a fixed place such as a home, usually with a good antenna.

Call sign

Your station's unique ID, given by the FCC.

Carrier

The radio signal itself before voice is added.

Channel

A specific frequency or pair of frequencies you tune to.

Coax

The cable that carries signal between a radio and its antenna.

Courtesy tone

A short beep that signals the end of a transmission.

CTCSS

Continuous Tone Coded Squelch System, the technical name for a PL tone.

dB

Decibel, a way to measure changes in signal strength.

DCS

Digital Coded Squelch, a digital version of a tone that opens a repeater.

Duplex

Transmitting on one frequency and receiving on another, as repeaters do.

Duty cycle

How much of the time a radio can transmit without overheating.

FCC

The Federal Communications Commission, which licenses radio in the United States.

FM

Frequency modulation, the mode used for most VHF and UHF voice.

Frequency

How many times a radio wave cycles each second, measured in hertz.

FRS

Family Radio Service, a no-license service on shared channels.

GMRS

General Mobile Radio Service, a licensed UHF personal radio service.

Handheld

A portable radio you carry in your hand, also called an HT.

HF

High frequency, the shortwave bands used for long-distance ham contacts.

Hotspot

A small personal node that links a radio to the internet.

Input

The frequency a repeater listens on.

Line of sight

A clear path between two antennas with nothing blocking it.

Mobile

A radio installed in a vehicle.

Monitor

Listening to a channel without transmitting.

MURS

Multi-Use Radio Service, a no-license service on five VHF channels.

Net

A scheduled on-air meeting where operators check in.

Node

A radio station tied into a network, often with a simplex channel.

Offset

The gap between a repeater's input and output frequencies.

Output

The frequency a repeater transmits on.

PL tone

A quiet tone sent with your voice so the repeater knows to listen.

Polarization

The direction an antenna's signal is oriented, usually vertical.

PTT

Push to talk, the key you hold to transmit.

Repeater

A station on high ground that receives a signal and retransmits it farther.

Roll call

A net in which each station is called in turn.

Simplex

Two radios talking directly on a single frequency.

Squelch

A control that mutes the speaker when nobody is transmitting.

SWR

Standing wave ratio, a measure of how well an antenna matches a radio.

Talk-around

Using the repeater's output frequency for direct radio-to-radio chat.

Timeout timer

A limit that cuts a transmission that goes on too long.

UHF

Ultra high frequency, about 300 MHz to 3 GHz. GMRS lives here.

VHF

Very high frequency, about 30 to 300 MHz.

VOX

Voice-activated transmit, so you do not have to press a key.