Abbreviations and acronyms

This is a non-exhaustive list of acronyms, abbreviations and conventions used in RadCom.

Towards the bottom of the page you will also find an explanation of common symbols plus some of the conventions used in GB2RS Local News and RadCom Club Calendar.

We welcome any suggested amateur radio-related additions to this list: if you would like to contribute new entries (or corrections) please email with the subject line Acronyms and format your additions as acronym <tab> expansion.


Abbreviations and acronyms list

Note: the abbreviations are capitalised correctly as they should appear and the expansions use capitals only where they are technically required – eg

k                  kilo (multiplier, x 1,000)
K                  kelvin
RSGB           Radio Society of Great Britain


A                 amp (ampere)

AC               activity contest

AC               alternating current

ADC            analogue to digital converter

AF               audio frequency (about 20Hz to about 20kHz)

AFS             Affiliated Society (contest)

AGC            automatic gain control

AGL            above ground level

Ah               amp-hour (eg battery capacity)

ALC             automatic level control

ALE             automatic link establishment

AM              amplitude modulation

AMTOR        amateur teleprinting over radio

AMU            antenna matching unit

APF             all pass filter

APRS          automatic packet reporting system

APSK          amplitude and phase shift keying

ARA            amateur radio association

ARC            amateur radio club

ARDF          amateur radio direction finding

ARG            amateur radio group

ARI              Associazione Radioamatori Italiani (Italian national society)

ARISS         Amateur Radio on the International Space Station

ARRL           American Radio Relay League

ARS            amateur radio society

AS               aircraft scatter

ASCII           American Standard Code for Information Interchange

ASK            amplitude shift keying

ASL            above sea level

ATS             amateur transmitting society

ATT            attenuator (radio panel marking)

ATU             antenna tuning unit

ATV             amateur television

b                   bit

B                   byte

BARTG        British Amateur Radio Teledata Group

BATC           British Amateur Television Club

BC               broadcast

BCI              broadcast interference

BERU          British Empire Radio Union (contest) (now known as the Commonwealth Contest)

BM              balanced modulator or balanced mixer

BNC            Bayonet Neill-Concelman (connector)

BPF             band pass filter

BPSK          binary phase shift keying

BVWS         British Vintage Wireless Society

BW              bandwidth

BWO          backward-wave oscillator

BWO          Bridge Wireless Office (eg aboard HMS Belfast)

C                 Celsius (centigrade)

C                 coulomb (unit of electric charge)

C&G            City and Guilds

CAR            carrier [level] (radio panel marking)

CASHOTA    Castles and Stately Homes on the Air

CAT             computer-assisted transceiver (or computer-aided)

CB               Citizen’s Band

CC               club contest

CC               Contest Committee

CCC            Commonwealth Century Club (operating award)

CDXC          Chiltern DX Club

CEPT          European Conference of Postal and Telecommunications Administrations

CHU           Canadian government standard time station on 3330, 7850 and 14670kHz

CLAR          clarifier (radio panel marking)

cm               centimetre (0.01m)

CoTY          Club of the Year

cps              characters per second

CQWW       CQ worldwide (contest programme)

CSC            Contest Support Committee

CTCSS        continuous tone coded squelch system

CV               curriculum vitae

CW              continuous wave (usually meaning Morse code)

DAC            digital to analogue converter

DARC          (and) district amateur radio club

DARC          Deutscher Amateur-Radio-Club (German national society)

DARS          (and) district amateur radio society

DATV           digital amateur television

dB               decibel

dBd             decibels relative to a dipole

dBi              decibels relative to an isotropic radiator

dBm            decibels relative to one milliwatt

DBM            double-balanced mixer

dBW            decibels relative to one watt

DC               direct current

DCC            Data Communications Committee

DCS            digital coded squelch

DDS            direct digital synthesiser

DIN             Deutsches Institut für Normung (German standards institute)

DMR           Digital Mobile Radio

DNR           digital noise reduction

DSB             double sideband

DSB-SC       double sideband suppressed carrier

DSP            digital signal processing

DSSC          dual sideband suppressed carrier

DSSS          direct sequence spread spectrum

D-Star          Digital Smart Technologies for Amateur Radio

DTMF          dual tone multi frequency (Touch-Tone)

DVB-S         digital video broadcasting – satellite

DVB-S2       digital video broadcasting – satellite, second generation

DX               long distance

DXCC           DX Century Club (award programme)

e                   base of the natural logarithm (2.71828…)

EIRP            effective isotropic radiated power

ele               [antenna] element(s)

ELF             extremely low frequency (300Hz to 3kHz)

EMC            electromagnetic compatibility

EME            earth-moon-earth (Moonbounce)

EEPROM     electrically erasable programmable read-only memory

EHF             extremely high frequency (30GHz to 300GHz)

EPROM       erasable programmable read-only memory

EQAM         Examination Quality Assurance Manager

ERP            effective radiated power

Es               Sporadic-E (propagation)

ESC            Examination Standards Committee

ESM            Examinations Standards Manager

ETCC          Emerging Technology Co-ordination Committee

EZNEC®    NEC-based antenna modelling software

F                 farad

F                 noise factor (note italic F)

f                  frequency (general)

FAQ           frequently asked questions

FCC            Federal Communications Commission (USA regulator)

FDM           frequency division multiplexing

FDIM          Four Days In May

FEC             forward error correction

FET             field-effect transistor

FH               frequency hopping

FM              frequency modulation

FMAC         FM activity contest

fps               feet per second

fps               frames per second

FS               full scale

FS               field strength

FSD             full scale deflection

FSK             frequency shift keying

FSTV          fast scan television

ft                 foot (about 305mm)

FWHM        full width half maximum

G                  giga (multiplier, x 1,000,000,000)

g                   gram

GAREC      Global Amateur Radio Emergency Communications Conference

Gb                gigabit (conventionally 1,073,741,824 bits or 1024Mb)

GB               gigabyte (conventionally 1,073,741,824 bytes or 1024MB)

GHz             gigahertz (thousand million cycles per second)

GMDX        Scottish DX Association

GP               ground plane

GPIO           general purpose input / output

H                 henry

h                  hour

HAAT        height above average terrain

HAREC      Harmonised Amateur Radio Examination Certificate

HF               high frequency (3MHz to 30MHz)

HFC            HF Convention (now RSGB Convention)

HFCC         HF Contest Committee

HPF            high pass filter

HVDC         high voltage direct current

Hz               hertz (cycles per second)

I                  current (A)

I                  in-phase component of a signal or magnitude

I/O             input / output

I/Q             in-phase and quadrature components of a signal

IC               integrated circuit

Ic                collector current

ISB              independent sideband

I2C               inter integrated circuit (digital communication)

IARP           International Amateur Radio Permit

IARU          International Amateur Radio Union

IF                intermediate frequency

ILLW          International Lighthouses and Lightships Week(end)

IMD             intermodulation distortion

in                 inch (about 25.4mm)

IOTA          Islands On The Air (awards programme and contest)

IP3              third-order intercept

IPO             intercept point optimisation

IRLP           Internet Radio Linking Project

IRQ              interrupt request

ISB              independent sideband

ISCAT        ionospheric scattering

ISS              International Space Station

ITU             International Telecommunications Union

J                   joule

JARL           Japan Amateur Radio League

JFET            junction field effect transistor

JOTA           Jamboree on the Air

JTDX          [K1]JT modes for DXing

K                  kelvin (NB: never °K)

K                 (Morse) invitation to transmit

k                  kilo (multiplier, x 1,000)

kb               kilobit  (conventionally 1024 bits)

kB               kilobyte (conventionally 1024 bytes)

kc/s             kilocycles per second (kilohertz)

kg                kilogram (1000g)

kHz              kilohertz (thousand cycles per second)

km               kilometre

ksps            kilosymbols per second

kW               kilowatt

kWh            kilowatt-hour (3,600,000 joules)

LAN             local area network

LCD             liquid crystal display

LED             light-emitting diode

LF               low frequency (30kHz to 300kHz)

LiFePO4    lithium iron phosphate (battery technology)

Li-ion         lithium-ion (battery technology)

LiPo           (also Li-Po) lithium-polymer (battery technology)

LO               local oscillator

LotW           Logbook of the World

LPF             low pass filter

LSB             least significant bit

LSB             lower sideband

LW              long wave (about 150kHz to 300kHz)

M                mega (multiplier, x 1,000,000)

m                metre

mA              milliamp (0.001A, 1000µA)

mAh           milliamp-hour (eg battery capacity)

MARL        Malta Amateur Radio League

Mb               megabit (conventionally 1048576 bits or 1024kb)

MB              megabyte (conventionally 1048576 bytes or 1024kB)

Mc/s            megacycles per second (megahertz)

MER            modulation error rate

MF              medium frequency (300kHz to 3MHz)

MFSK          multiple frequency shift keying

MHz            megahertz (million cycles per second)

mm              millimetre (0.001m)

MoD            Ministry of Defence

MOSFET     metal oxide semiconductor field effect transistor

MOTA          Museums on the Air

MOTA          Mills on the Air

MPEG         Moving Picture Experts Group

MR              moonrise

MS              meteor scatter

MS              moonset

MSF           UK NPL standard time service broadcast on 60kHz

MSHV        meteor scatter [software by LZ2]HV

Msps           megasymbols per second

MSB            most significant bit

MUF           maximum usable frequency

mult             multiplier (contesting)

MW             medium wave (roughly 525-1600kHz)

MW             megawatt

n                 nano (multiplier, x 0.000,000,001)

NB              noise blanker

NB              nota bene (note well)

NEC            Numerical Electromagnetics Code

NF               noise figure

NF               noise floor

NOAA         National Oceanic and Atmospheric Administration (USA)

NFD             National Field Day

NiCd            nickle-cadmium (battery technology)

NiFe            nickle-ion (battery technology)

NiMH         nickle-metal hydride (battery technology)

NPL            National Physical Laboratory (UK)

NRC            National Radio Centre

NRRL           Norsk Radio Relæ Liga

NVIS            near vertical incidence skywave

NZART        New Zealand Association of Radio Transmitters

OCXO          oven controlled crystal oscillator

OCFD          off-centre fed dipole

ODX             longest distance (best DX)

OEM           original equipment manufacturer

OLED          organic light-emitting diode

OOK            on-off keying

OQRS          online QSL request

OTA             on the air

p                  pico (multiplier, x 0.000,000,000,001)

PA               power amplifier

PCM            pulse code modulation

PD               potential difference

PD               product detector

pk                peak

pk-pk           peak to peak

PLL             phase-locked loop

PM              phase modulation

PMR            private mobile radio

PN               phase noise

PRNG         pseudo-random noise generator

PROM         programmable read-only memory

pp                peak to peak

p-p               peak to peak

PPM            pulse position modulation

PSK            phase shift keying

PTT           push to talk

PV               photovoltaic

PW              Practical Wireless

PZK             Polski Zwi?zek Krótkofalowców (Polish national society)

Q                 quadrature component of a signal or magnitude

Q                 quality factor

QAM            quadrature amplitude modulation

QPSK          quadrature phase shift keying

QRA            callsign

QRM            interference from artificial sources

QRN            interference from natural sources

QRO            high power

QRP            low power (usually ?5W)

QRPp          very low power (often well under 1W)

QRS            please send slower

QRS            slow Morse code

QRSs          extremely slow Morse code (seconds to hours per dit)

QRT             cease operating

QRV            (ready to) operate

QRX            wait

QRZ            who is calling me?

QSB            fading

QSK            listening (or interrupting) between transmissions

QSL             confirmation of contact

QSO            communication

QST             general call to all stations (also, ARRL monthly magazine)

QSX             I am listening on [frequency]

QSY            change frequency

QTH             position (eg address)

QTHR          ‘registered’ position (eg, address as listed in callbook)

Qu               unloaded quality factor

QUCS          Quite Universal Circuit Simulator

RAC            Radio Amateurs of Canada

RadCom      RSGB monthly magazine for Members

RBN            reverse beacon network

RBTV           reduced bandwidth television

RC               radio club

RC               resistor-capacitor (network, time constant etc)

RCF             Radio Communications Foundation

REF               Réseau des Émetteurs Français (French national society)

REP            Rede dos Emissores Portugueses (Portuguese national society)

RF               radio frequency

RFI              radio frequency interference

RIT             receiver incremental tuning

RL               return loss

RMDR        reciprocal mixing dynamic range

RMS            root mean square

RNLI           Royal National Lifeboat Institution

ROA            Radio Officers’ Association

RoLo            Rolling Locators (contest)

ROM           read-only memory

RS               readability, signal

RSARS       Royal Signals Amateur Radio Society

RSGB          Radio Society of Great Britain

RST             readability, signal, tone

RTTY           radio teletype

Rx               receive (or receiver)

s                 second

S                 siemens (unit of conductance)

SCART        Syndicat des Constructeurs d’Appareils Radiorécepteurs et Téléviseurs (French Radio and Television Receiver Manufacturers’ Association)

SCC            special contest callsign

SDR            software defined radio

SFDR         spurious-free dynamic range

SFI            solar flux index

SHF             super high frequency (3GHz to 30GHz)

SK               silent key (the person is dead)

SMA            sub miniature version A connector

SMB            sub miniature version B connector

SMC            sub miniature version C connector

SMD            surface mount device

SMT            surface mount technology

S/N             signal to noise (ratio)

S/N             serial number

SNR            signal to noise ratio

SO2R          single operator two radios

SO2V          single operator two VFOs

SOTA          Summits on the Air (awards programme)

SPI              serial peripheral interface

SR               symbol rate

SS               spread spectrum

SSB            single sideband

SSTV           slow scan television

SWR           standing wave ratio

T                 tera (multiplier, x 1,000,000,000,000)

T                 turns (on an inductor)

TCXO           temperature compensated crystal oscillator

TD               time division

TDM            time division multiplexing

TEC            Training and Education Committee

TEC            total electron content (propagation)

TL                transmission line

TNC             threaded Neill-Concelman (connector)

TNC             terminal node controller

TOR             teleprinter over radio

TOR            The Onion Router (internet anonymity network)

TS               transport stream

Tx                transmit (or transmitter)

µ                 micro (multiplier, x 0.000,001)

µA               microamp (0.000,001A)

UBA            Royal Union of Belgian Radio Amateurs

UHF             ultra high frequency (300MHz to 3GHz)

UKAC          UK Activity Contest

UKSMG      United Kingdom Six Metre Froup

UKuG          United Kingdom Microwave Group

URE            Unión de Radioaficionados Españoles

US               United States

USA            United States of America

USB            Universal Serial Bus

USB            upper sideband

UTC             Coordinated Universal Time

V                 volt

VCO            voltage controlled oscillator

VERON        Vereniging voor Experimenteel Radio Onderzoek Nederland (Dutch national society)

VFO            variable frequency oscillator

VHF             very high frequency (30MHz to 300MHz)

VHFCC        VHF Contest Committee

VLF             very low frequency (3kHz to 30kHz)

VoIP            voice over internet protocol

VOX             voice operated switch

VXO             variable crystal oscillator

W                watt

WAB           Worked All Britain (awards programme)

WAC           Worked All Continents (award programme)

WAS           Worked All States (awards programme)

WARC         World Administrative Radio Congress

WAZ            Worked All Zones (award programme)

WDM           wavelength division multiplexing

Wi-Fi           type of wireless networking

WIA             Wireless Institute of Australia

WLAN          wireless local area network

WPM           words per minute

WPS           Wi-Fi Protected Setup

WRC           World Radiocommunication Conference

WSPR         Weak Signal Propagation Reporter

WWV          US Government standard frequency and time station on 2.5, 5, 10, 15, 20 and 25MHz

X                 impedance

xcvr             transceiver

xtal              crystal

XYL             ex YL (wife)

yd                yard (about 0.914m)

YL               young lady

YOTA        Youth on the Air

Z                 impedance

Zo                characteristic impedance



Common symbols

~                 approximately (or almost) equal to

?                 approximately (or almost) equal to

?                 not equal to

?                 identical to (or, in logic expressions, iff)

±                 plus or minus

?                 difference (among other meanings)

?                 less than or equal to

?                 greater than or equal to

°                  degree (eg temperature or angle)

µ                 micro (multiplier, x 0.000,001)

?                 infinity (or infinite)

?                 wavelength

?                 pi (3.14159…)

?                 frequency in radians (equal to 2 x ? x frequency in Hz)

?                 ohm

”                  inch (25.4mm)

”                  second (time or angle)

‘                  foot (12in, ~305mm)

‘                  minute (time or angle)

?                 square root



GB2RS Local News and RadCom Club Calendar conventions

Club net       Members of a club having a turns-based conversation under a Net Controller

Club night     General, un-themed meeting at normal club meeting-place

On the air     Club members operating the club radio equipment, normally on club premises unless specified otherwise

Open net      Open to all turns-based conversation under a Net Controller

Radio night   Club members operating the club radio equipment, normally on club premises



We apologise for the poor formatting of these lists; work is underway to improve their presentation.