Jargon BusteR

Like many activities in this world the hobby of radio listening has acquired its own language, or Jargon. Some dates back to the earliest days of wireless communications but each generation of technology has spawned its own slang and technical terms.

In the early days of wireless radio operators generated a a large vocabulary of abbreviations and codes that were easier and quicker to transmit using Morse code than the full phrase they represented. Some of these codes are widely used by radio enthusiasts today, whereas other remain the preserve of those radio amateurs who still operate with Morse code.


73 A short hand code from the earliest days of telegraphy & wireless meaning “best wishes”. Still used by radio enthusiasts today.

A-index A daily index of geomagnetic activity derived as the average of the eight 3-hourly a indices. This is an indicator of how MW signals will propagate or travel around the world. Example

AM Amplitude modulation. The main method of transmitting signals in the long and medium wave bands. Often used in the North America to mean “medium wave”.

AM DX Often used in North America to mean MW DX - see MW DX.

BCB Broadcast band. An older North American term refering to the MW band.

CW Continuous Wave. But this actually describes a transmission where a continuous carrier is switched on & off to send Morse code characters. Sometimes more loosely applied to any means of transmitting Morse code. Used by NDB's.

DRM Digital Radio Mondiale. A new form of digital modulation being used by some stations in the MW band instead of AM. Currently used mostly in Europe. More information

DX Literally “Distance”. A code from the earliest days of radio meaning a far away signal. Sometimes used to mean anything that is normally difficult to hear.

DXer A radio hobbiest interested in DXing.

DX-ing The art or activity of listening to distant signals.

DX-pedition An expedition to a location by DXers specifically to listen to DX signals. Usually involves a trip to a site where interference is less or where there is space for advanced aerials. Further information

IBOC In Band On Carrier. A new proprietory form of hybrid modulation that combines AM and digital modulation on one carrier. Now quite widely used in the USA. IBOC and DRM are not compatible.

ID Identification. More information

Ionosphere The region of the earth's upper atmosphere containing a small percentage of free electrons and ions produced by photoionization of the constituents of the atmosphere by solar ultraviolet radiation at very short wavelengths (<1000 angstroms). The ionosphere significantly influences radiowave propagation of MW & LW frequencies. Further reading

IRC International Reply Coupon. A coupon that can be purchased from a post office and may be exchanged in any member country of the Universal Postal Union for the minimum postage payable on international unregistered airmail letters; often used by DXers along with their reception reports as means to cover return postage for the radio station.

An International Reply Coupon (IRC) is used when you send mail to a country other than your own and you want to pay for return postage. It is redeemable in any country which participates in the Universal Postal Union. Think of it as "Stamp Currency".

Actually it would be more appropriate to call them "CRIs" (Coupon Réponse International), since the official language of the UPU is French.


The person who you send them to can take them to their local post office, and trade them in for the equivalent amount of non-registered air mail postage. This will allow them the courtesy of providing you a reply.

The main part of the coupon is printed in French, regardless of the country where it was purchased. The English translation on the reverse side reads "This coupon is exchangeable in any country of the Universal Postal Union for for the minimum postage for an unregistered priority item or an unregistered letter sent by air to a foreign country."

IRC back

IRCs are available from your local post office. Check with them for your cost locally. You may also want to check your country's online postal resources, if available.

To visit the website of the Universal Postal Union click here.

kHz kilohertz. A unit of measurement of frequency. 1kHz = 1000Hz.

K-index A 3-hourly quasi-logarithmic local index of geomagnetic activity relative to an assumed quiet-day curve for the recording site. Range is from 0 to 9. This is an indicator of how MW signals will propagate or travel around the world.

LF Low Frequencies: 30kHz-300kHz.

Long Wave Refers to the band of frequencies between 148.5 - 283.5kHz used for broadcasting in Europe & Asia.

LW See Long Wave.

Medium Frequency A term used to define the radio spectrum between 300kHz and 3000kHz

Medium Wave Refers to the band of frequencies between approximately 520kHz and 1700kHz, though the definition depends on frequency allocations that differ slightly in different parts of the world.

MG Middengolf. Dutch for “Medium Wave”.

MW See Medium Wave.

MWC Medium Wave Circle.

MW DX "Long distance medium wave listening" (verb) or "medium wave signals from far away" (noun)

MWN Medium Wave News. More information

Navtex A digital transmission method used for maritime information transmissions on 518 and 490kHz.

NDB Non directional beacon. A radio navigation beacon that mostly operate between 280-500kHz but some are in the MW band. Most continuously transmit a simple callsign in Morse code.

OM Ondes Moyennes. French for “Medium Wave”. Onda Media. Spanish for “Medium Wave”.

QRM An old radio code meaning “interference” from one radio signal degrading reception of another. Further reading

QRN An old radio code meaning “noise”. Usually refers to natural noise such as static or thunderstorm noise, but can also mean man-made electrical noise. More information

QSL A card or letter (or now an e-mail) sent by a station to a listener to confirm that the listener heard the station. More information

QTH An old abbreviation for location of the radio transmitter (or the listener).

UTC Coordinated Universal Time is a high-precision atomic time standard which approximately tracks Universal Time (UT). It is the basis for legal civil time all over the Earth: time zones around the world are expressed as positive and negative offsets from UTC. In this role it is also referred to as Zulu time (Z), or using the historical term "Greenwich Mean Time" (GMT). http://www.npl.co.uk/time/

VLF Very Low Frequencies: 3kHz-30kHz.

X-Band Extended mediumwave band; an addition to the traditional MW broadcast band introduced in some countries in the 1990's (1610-1700 kHz in the Western hemisphere, 1611-1702 kHz in the Eastern hemisphere) Not allocated for broadcasting in Europe or Africa.