Abbreviations and acronyms
This is a non-exhaustive list of acronyms, abbreviations and conventions used in RadCom.
At the bottom of the page you will also find some of the conventions used in GB2RS Local News and RadCom Club Calendar plus an explanation of common symbols used in RadCom and other RSGB publications. Some of the definitions may vary slightly from those published elsewhere: the meanings listed here reflect their usage in RadCom.
(As time permits, I am slowly going through the list and adding links to relevant definitions and/or organisations etc. Whilst many of the subjects, for example ARDF, are covered on the RSGB website I have elected to use Wikipedia as the primary reference source, at least for the initial run-through. The exception to this is organisations, such as ARRL, where I link to their home page. You’re welcome to open a discussion with me about this via the email address below. Giles, G1MFG, 29 July 2021)
We welcome any suggested amateur radio-related additions to this list: if you would like to contribute new entries (or corrections), please email radcom@rsgb.org.uk with the subject line Acronyms and if possible 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 where they are properly required – eg
k kilo (multiplier, x 1,000)
K kelvin (temperature)
RSGB Radio Society of Great Britain
A amp (ampere)
AC activity contest
ADC analogue to digital converter
ADIF Amateur Data Interchange Format
ADSL asymmetric digital subscriber line
AF audio frequency (about 20Hz to about 20kHz)
AFS Affiliated Society (contest)
Ah amp-hour (eg battery capacity)
ALE automatic link establishment
AMBE Advanced Multi-Band Excitation
AMBE+ more advanced version of AMBE
AMTOR amateur teleprinting over radio
AOTA Airfields on the Air
APF all pass filter
APRS automatic packet reporting system
APSK amplitude and phase shift keying
APT automatic picture transmission
APT Asia-Pacific Telecommunity
ARA amateur radio association
ARC amateur radio club
ARDF amateur radio direction finding
AREDN Amateur Radio Emergency Data Network
ARG amateur radio group
ARI Associazione Radioamatori Italiani (Italian national society)
ARISS Amateur Radio on the International Space Station
AROS Amateur Radio Observation Service (replaced by RSGB OAS)
ARRL American Radio Relay League
ARS amateur radio society
ASCII American Standard Code for Information Interchange
ASL above sea level
ASTU antenna system tuning unit
ATA AT attachment (now PATA (qv))
ATC amateur transmitting club
ATNO all-time new one
ATS amateur transmitting society
ATT attenuator (radio panel marking)
Az azimuth
b bit
B byte
BARTG British Amateur Radio Teledata Group
BATC British Amateur Television Club
BC broadcast
BCI broadcast interference
BEAMA British Electrotechnical and Allied Manufacturers’ Association
BERU British Empire Radio Union (contest) (now known as the Commonwealth Contest)
BLM Board liaison member
BM balanced modulator or balanced mixer
BNC Bayonet Neill-Concelman (connector)
BPF band pass filter
BPSK binary phase shift keying
BT Bluetooth
BVWS British Vintage Wireless Society
BW bandwidth
BWO Bridge Wireless Office (eg aboard HMS Belfast)
C Celsius (centigrade)
C coulomb (unit of electric charge)
C&G City and Guilds
CAN controller area network (bus)
CAPEX capital expenditure
CAR carrier [level] (radio panel marking)
CASHOTA Castles and Stately Homes on the Air
CAT computer-assisted transceiver (or computer-aided)
CATV Community Access Television (or Community Antenna Television) (cable TV)
CB Citizen’s Band
CC club contest
CC Contest Committee
CCC Commonwealth Century Club (operating award)
CDXC Chiltern DX Club
CE chip enable (control signal)
CEPT European Conference of Postal and Telecommunications Administrations
CFL compact fluorescent lamp
CHU Canadian government standard time station on 3330, 7850 and 14670kHz
CIGRÉ Conseil International des Grands Réseaux Électriques (Council for Large Electrical Systems)
CITEL Comisión Interamericana de Telecomunicaciones (Inter-American Telecommunication Commission)
CLAR clarifier (radio panel marking)
CLK clock (control signal)
cm centimetre (0.01m)
CMOS complementary metal-oxide-semiconductor
Codec2 Family of audio vocoders created by VK5DGR, also the basis of FreeDV on HF
condx condition(s)
CoTY Club of the Year
cps characters per second
cps cycles per second (Hz) (deprecated)
CQWW CQ worldwide (contest programme)
CRC cyclic redundancy check
CRT cathode ray tube
CSC Contest Support Committee
CTCSS continuous tone coded squelch system
CTS clear to send
CV curriculum vitae
c/w complete with
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
dBc decibels relative to carrier
dBd decibels relative to a dipole
dBFS decibels relative to full scale
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
DFIG doubly fed induction generator
DIN Deutsches Institut für Normung (German standards institute)
DMA direct memory access
DMR Digital Mobile Radio
DNR digital noise reduction
DOCSIS Data Over Cable Service Interface Specification
DORA Directory Of Resources and Advice
dPMR Digital Private Mobile Radio
DSB double sideband
DSC digital selective calling
DSB-SC double sideband suppressed carrier
DSL digital subscriber line
DSP digital signal processing (or processor)
DSSC dual sideband suppressed carrier
DSSS direct sequence spread spectrum
D-Star Digital Smart Technologies for Amateur Radio
DTL diode-transistor logic
DTMF dual tone multi frequency (Touch-Tone)
DUT device under test
DV digital voice
DVB-S digital video broadcasting – satellite
DVB-S2 digital video broadcasting – satellite, second generation
DVB-T digital video broadcasting – terrestrial
DVB-T2 digital video broadcasting – satellite, second generation
DVSI Digital Voice Systems Inc, USA-based creators of IMBE and AMBE
DX long distance
DXCC DX Century Club (award programme)
DXpedition one or more amateurs going to an (usually infrequently activated) location to activate the square, country, island (or whatever) for a short time for the benefit of those wanting to work that place
e base of the natural logarithm (2.71828…)
ECSS exalted-carrier selectable-sideband (zero beat tuning to receive AM on SSB mode)
EDR Experimenterende Danske Radioamatører (Danish national society)
EEPROM electrically erasable programmable read-only memory
EG Examinations Group
EIRP effective isotropic radiated power
El elevation
ele [antenna] element(s)
ELF extremely low frequency (300Hz to 3kHz)
EMC electromagnetic compatibility
EME earth-moon-earth (Moonbounce)
EMR enhanced monitor request
EHF extremely high frequency (30GHz to 300GHz)
EMP electromagnetic pulse
ENA enable
ENR excess noise ratio
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
EU European Union
EUDXF European DX Foundation
EUT equipment under test
EUV extreme ultraviolet
EW electronic warfare
EZNEC® NEC-based antenna modelling software
F farad
F noise factor (note italic F)
f frequency (general)
foF2 critical frequency (highest frequency returned by the F2 layer)
FAQ frequently asked questions
FCC Federal Communications Commission (USA regulator)
FDD frequency division duplexing
FDM frequency division multiplexing
FDIM Four Days In May
FEC forward error correction
FET field-effect transistor
FFT Fast Fourier Transform
FFTW fastest Fourier Transform in the West
FH frequency hopping
FIR far infrared
FM frequency modulation
FMAC FM activity contest
FOSS free open-source software
FP floating point
FPGA field programmable gate array
fps feet per second
fps frames per second
FPV first person view (or video)
FS full scale
FS field strength
FSD full scale deflection
FSK frequency shift keying
FSTV fast scan television
ft foot (about 305mm) (or feet)
FTTP fibre to the premises
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)
GC good condition
GE General Electric (business)
GEC General Electric Company
GHz gigahertz (thousand million cycles per second)
GIRO Global Ionospheric Research Organisation
GLS general lighting service
GM General Manager (RSGB)
GM group mode
GMDX Scottish DX Association
GMRT Scottish Microwave Round Table
GNSS global navigation satellite system
GNU GNU’s Not Unix! [sic – Ed]
GP ground plane
GPIO general purpose input / output
GPO General Post Office
GPRS general packet radio service
GPS Global Positioning System
GSM Global System for Mobile communications
GWO good working order
H henry
h hour
HAAT height above average terrain
HAREC Harmonised Amateur Radio Examination Certificate
HD high definition
HDTV high definition television
HEVC high efficiency video coding
HF high frequency (3MHz to 30MHz)
HFC HF Convention (now RSGB Convention)
HFC hybrid fibre coaxial
HFCC HF Contest Committee
hFE bipolar transistor DC current gain
HPF high pass filter
HPWPT high power wireless power transfer
HS heatsink
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
ICAS intermittent commercial / amateur service
Ic collector current
ICE in-circuit emulation
Id drain current
ID (or id) inside diameter
IDE integrated development environment
IDE integrated drive electronics
ISB independent sideband
I2C inter integrated circuit (digital communication)
IARP International Amateur Radio Permit
IARU International Amateur Radio Union
ICNIRP International Commission on Non-Ionizing Radiation Protection
IF intermediate frequency
IGBT insulated-gate bipolar ransistor
ILLW International Lighthouses and Lightships Week(end)
IMBE Improved Multi-Band Excitation
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
IR infrared
IRC international reply coupon
IRC internet relay chat
IRLP Internet Radio Linking Project
IRQ interrupt request
ISB independent sideband
ISBN international standard book number
ISCAT ionospheric scattering
ISM Industrial, Scientific and Medical
ISP internet service provider
ISS International Space Station
ITU International Telecommunications Union
ITS Institute for Telecommunication Sciences (USA)
J joule
JARL Japan Amateur Radio League
JFET junction field effect transistor
JOTA Jamboree on the Air
JPL Jet Propulsion Laboratory (NASA)
JTAG Joint Test Action Group
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) (deprecated)
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
lb pound
LCD liquid crystal display
LDO low dropout
LDPC low density parity check
LED light-emitting diode
LF low frequency (30kHz to 300kHz)
LHS left hand side
LISN line impedance stabilisation network
LiFePO4 lithium iron phosphate (battery technology)
Li-ion lithium-ion (battery technology)
LiPo (also Li-Po) lithium-polymer (battery technology)
LNA low noise amplifier
LNTA low noise transconductance amplifier
LO local oscillator
LotW Logbook of the World
LP log periodic
LPF low pass filter
LSB least significant bit
LSB lower sideband
LVD Low Voltage Directive
LVDS low voltage differential signalling
LW long wave (about 150kHz to 300kHz)
LWIR long wavelength infrared
M mega (multiplier, x 1,000,000)
m metre
M17 an open source DV mode
mA milliamp (0.001A, 1000µA)
mAh milliamp-hour (eg battery capacity)
MARC Marconi Amateur Radio Circle (Malta)
MARL Malta Amateur Radio League
Mb megabit (conventionally 1048576 bits or 1024kb)
MB megabyte (conventionally 1048576 bytes or 1024kB)
MC master of ceremonies
Mc/s megacycles per second (megahertz) (deprecated)
MER modulation error rate
MF medium frequency (300kHz to 3MHz)
MFSK multiple frequency shift keying
MGM machine-generated mode
MHz megahertz (million cycles per second)
MIMO multiple input multiple output
MLS maximum (or maximal) length sequence
ML&S Martin Lynch & Sons (retailer)
mm millimetre (0.001m)
MMDVM Multi-Mode Digital Voice Modem
MO multiple operator
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
MSK minimum-shift keying
Msps megasymbols per second
MSB most significant bit
MTBF mean time before failure
MUF maximum usable frequency
mult multiplier (contesting)
MW medium wave (roughly 525-1600kHz)
MW megawatt
MWIR medium wavelength infrared
n nano (multiplier, x 0.000,000,001)
NAND not-AND (logic function)
NASA National Aeronautics and Space Administration (USA)
NB noise blanker
NB nota bene (note well, take note of)
NDB non-directional beacon
NEC Numerical Electromagnetics Code
NEC National Exhibition Centre
NF noise figure
NF noise floor
NFD National Field Day
NMEA National Marine Electronics Association (USA)
NOAA National Oceanic and Atmospheric Administration (USA)
NOR not-OR (logic function)
NiCd nickel-cadmium (battery technology)
NiFe nickel-ion (battery technology)
NiMH nickle-metal hydride (battery technology)
NIR near infrared
nm nanometre (1×10-9m)
NMOS N-type metal-oxide-semiconductor
NPL National Physical Laboratory (UK)
NRC National Radio Centre
NRRL Norsk Radio Relæ Liga (Norwegian national society)
NSD noise spectral density
NTP network time protocol
NTSC National Television Standards Committee (USA)
NVIS near vertical incidence skywave
NXDN DV mode created by Icom and Kenwood
Nyquist (also Nyquist rate or Nyquist Frequency) refers to sampling rates; see links for details
NZART New Zealand Association of Radio Transmitters
OAS (RSGB) Operating Advisory Service
OBO on behalf of
OBO or best offer
OCXO oven controlled crystal oscillator
OCFD off-centre fed dipole
OD (or od) outside diameter
ODX longest distance (best DX)
OEM original equipment manufacturer
OIRO offer(s) in the region of
OLED organic light-emitting diode
ONO or near offer
OOK on-off keying
OPEX operational expenditure
OQPSK offset quadrature phase-shift keying
OQRS online QSL request
osc oscillator
OTA on the air
OVNO or very near offer
oz ounce, about 28.3g
p pico (multiplier, x 0.000,000,000,001)
P25 Phase 1 Project 25 Phase 1, an early DV mode used by public services in the USA
P25 Phase 2 Project 25 phase 2, similar to Phase 1 in usage but is a TDMA system
PA power amplifier
PAL phase alternating line (analogue TV colour encoding system)
PATA parallel ATA, an interface standard for disk drives
PBT passband tuning
PD product detector (frequency mixing demodulator for AM and SSB)
PE protective earth (note that requirements vary between and even inside jurisdictions)
pk peak
pk-pk peak to peak
PLC powerline communication (eg domestic internet extenders that run signals through existing mains wiring)
PMOS P-type metal-oxide-semiconductor
PMR private (or professional) mobile radio
PN phase noise
POTS plain old telephone system (or service)
PPR pulses per revolution
PPR prior permission required
PRNG pseudo-random noise generator
PROM programmable read-only memory
pp peak to peak
p-p peak to peak
P&P packing and postage
PSTN public switched telephone network
PTT push to talk
PV photovoltaic
PZK Polski Zwiazek Krótkofalowców (Polish national society)
Q quadrature component of a signal or magnitude
QAM quadrature amplitude modulation
QP quasi-peak (detector for EMC measurements)
QPSK quadrature phase shift keying
QRA callsign
QRA Q-ary repeat-accumulate
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,
QST ARRL monthly magazine for members
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
RA Radiocommunications Agency (superseded by Ofcom in 2003)
RadCom RSGB monthly magazine for Members
RAF RadioAmateurs France (Société nationale française)
RAF Royal Air Force
RAFARS Royal Air Force Amateur Radio Society
RAOTA Radio Amateurs Old Timers’ Association
R&TTE Radio Equipment and Telecommunications Terminal Equipment
RAYNET UK Radio Amateurs’ Emergency Network
RBN reverse beacon network
RBTV reduced bandwidth television
RC radio club
RC resistor-capacitor (network, time constant etc)
RCF Radio Communications Foundation
RDRc Russian Digital Radioamateur Club
RED Radio Equipment Directive
REF Réseau des Émetteurs Français (French national society)
REIN repetitive electrical impulse noise
REP Rede dos Emissores Portugueses (Portuguese national society)
RF radio frequency
RFI radio frequency interference
RHS right hand side
RIT receiver incremental tuning
RL return loss
RMDR reciprocal mixing dynamic range
RMS root mean square
RNAS Royal Naval Air Station
RNLI Royal National Lifeboat Institution
ROA Radio Officers’ Association
RoLo Rolling Locators (contest)
ROM read-only memory
RP reverse polarity (eg RP-SMA)
RS readability, signal
RS register slect
RSARS Royal Signals Amateur Radio Society
RSGB Radio Society of Great Britain
RST readability, signal, tone
RTL resistor-transistor logic
RTO regional telecommunication organisation
RTS request to send
RTTY radio teletype
RW read / write
R/W read / write
Rx receive (or receiver)
s second
S siemens (unit of conductance)
S&P search and pounce
SAW surface acoustic wave
SCART Syndicat des Constructeurs d’Appareils Radiorécepteurs et Téléviseurs (French Radio and Television Receiver Manufacturers’ Association)
SCC special contest callsign
SCL serial clock (I2C)
SD Secure Digital
SD standard definition
SDA serial data (I2C)
SDR software defined radio
SECAM Séquentiel couleur à mémoire
SFDR spurious-free dynamic range
SFI solar flux index
SHF super high frequency (3GHz to 30GHz)
SI Système international (d’unités) (international system of units)
sic sic erat scriptum, “thus was it written” (meaning “this is an exact quotation, not a transcription error”)
SISO single input single output
SK silent key (the person is dead)
sked scheduled contact (eg Alice calls Bob every Monday at 2pm on 145.450MHz)
SLALIB Subprogram Library A
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
SO single operator
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
SSN smoothed sunspot number
SSPA solid state power amplifier
SSTV slow scan television
STARS Support to the Amateur Radio Service (IARU programme)
STEM science, technology, engineering and mathematics
STL small transmitting loop
SW short wave (roughly 2-30MHz)
SWL short wave listener
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
TDD time division duplexing
TDM time division multiplexing
TEC Training and Education Committee
TEC total electron content (propagation)
TL transmission line
TLA three-letter acronym (or abbreviation)
TNC threaded Neill-Concelman (connector)
TNC terminal node controller
TOR teleprinter over radio
TOR The Onion Router (internet anonymity network)
TRF tuned radio frequency
tropo tropospheric propagation
TRRG Tenby Radio Repeater Group
TS transport stream
TTL transistor-transistor logic
TV television
TWG technical working group
Tx transmit (or transmitter)
µ micro (multiplier, x 0.000,001)
µA microamp (0.000,001A)
UBA Royal Union of Belgian Radio Amateurs
UBN Unique, Busted or Not-in-the-log (contesting)
UHF ultra high frequency (300MHz to 3GHz)
UK United Kingdom of Great Britain and Northern Ireland
UK&CD United Kingdom [of Great Britain and Northern Ireland] and Crown Dependencies
UKAC UK Activity Contest
UKSMG United Kingdom Six Metre Group
UKuG United Kingdom Microwave Group
uPVC unplasticised polyvinyl chloride
URE Unión de Radioaficionados Españoles (Spanish national society)
USB upper sideband
UTC Temps Universel Coordonné (Coordinated Universal Time)
V volt (unit for electric potential)
VCO voltage controlled oscillator
VCXO voltage controlled crystal oscillator
VDSL very high bit-rate digital subscriber line
VERON Vereniging voor Experimenteel Radio Onderzoek Nederland (Dutch national society)
VFO variable frequency oscillator
VGC very good condition
VHF very high frequency (30MHz to 300MHz)
VHFCC RSGB VHF Contest Committee
VLF very low frequency (3kHz to 30kHz)
VLNA very low noise amplifier
VOACAP Voice of America Coverage Analysis Program
VoIP voice over internet protocol
VPL visual programming language
Vs supply voltage
VSWR voltage standing wave ratio
VXO variable crystal oscillator
WAB Worked All Britain (awards programme)
WAC Worked All Continents (award programme)
WAS Worked All States (awards programme)
WARC World Administrative Radio Congress (or Conference)
WAZ Worked All Zones (award programme)
WDM wavelength division multiplexing
WHY what have you? (what do you have [to offer])
Wi-Fi type of wireless networking
WIA Wireless Institute of Australia
WKD (or wkd) worked
WLAN wireless local area network
WPM words per minute
WRC World Radiocommunication Conference
WRPSA World Radio Propagation Study Association
W&S Waters and Stanton (retailer)
WSPR Weak Signal Propagation Reporter
WWV US Government standard frequency and time station on 2.5, 5, 10, 15, 20 and 25MHz
WX weather
X (electrical) impedance (also, Z)
xcvr transceiver
XFC transmit frequency check
XIT transmit incremental tuning
xmtr transmitter
XOR exclusive-OR (logic)
xtal crystal
XTLA eXtended three-letter acronym (or abbreviation) (ie four letters)
XYL ex YL (wife)
yd yard (3 feet, or about 0.914m)
YL young lady
YMMV your mileage may vary (ie, the results you get may be different from the results given as an example)
YOTA Youth on the Air
Z (electrical) impedance (also, X)
ZHR zenithal hourly rate (of meteors)
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
Final note: the ‘right’ way to express a figure and a unit puts a space between them, eg length of eight and a half metres should be written as 8.5 m. However, RadCom does not include a space, partly for typesetting reasons, so we would print it as 8.5m. We know we’re wrong – but at least we are consistently wrong.
