Short Wave Frequency Bands

Introduction

The frequencies and bands used for short-wave radio broadcasting are agreed internationally by an agency of the United Nations known as the International Telecommunications Union (ITU), and all countries should adhere to the ITU's rules. However, not all stations stick within the agreed bands, indeed many choose to use frequencies just outside the official bands where there are fewer competing broadcast stations and thus less interference (this is known as 'out-of-band broadcasting'), but most do remain within the agreed limits. If you're just tuning around short wave and looking for stations, the official bands are definitely the place to start. Also remember, radio frequencies below around 12000 kHz work best when it's dark (at night!) and those above around 9000 kHz work best during daylight hours. Most short-wave radio stations are on a 5 kHz raster meaning that their frequency in kHz will either end with a '5' or a '0' (eg 15205 or 6110 kHz).

The Short Wave Broadcasting Bands

There are fourteen discrete bands which are allocated by the ITU for broadcasting over the short wave frequency range:

Note that on the main short-wave.info web-site, the range of frequencies listed for these bands in the pull-down menu are somewhat wider to ensure that transmissions from any of the aforementioned out-of-band broadcasters are also captured.

Radio Amateurs

Radio Amateurs (fondly referred to as 'hams') use a different set of frequencies to broadcasters and also use a different form of modulation for speech called single side band (SSB) instead of amplitude modulation (AM) used by international broadcasters. Receiving SSB needs specialist equipment but even relatively low cost receivers will often do the job. Using a normal AM receiver, SSB sounds as if someone is talking with several socks stuffed in their mouth. Radio hams use morse code (CW) and digital transmission modes as well, which require additional equipment to decode.

Radio amateur transmissions are not listed in the short-wave.info database, but the frequencies to listen out on are listed below.

Other Short Wave Frequencies

There are lots of other short-wave frequencies which are used for all manner of purposes including ship-to-shore communications (maritime), air traffic control (aeronautical), military and defence, weather information and even spy stations and radio pirates. Broadcasters normally use AM (though some are now digital), whereas most of the other users are either digital or use SSB as with the radio hams. It therefore requires specialist receivers to listen to these other services and indeed under some jurisdictions it is illegal to do so, however there is a world of fun to be had on short wave if you have the time and patience.

The only other short-wave frequencies which it is usually legal to receive and which require no specialist equipment are 'time and frequency standard stations'. These are stations which use very accurate transmitters controlled by atomic clocks, and thus serve as highly accurate references. They are therefore very useful for checking the accuracy of your receiver. They also transmit time information, usually as a series of 'ticks' each second plus spoken messages each minute. The following stations are believed to be on-air:

Note that time signal stations are not generally listed in the main short-wave.info database and that you won't necessarily hear all of them. Some have much higher transmitter powers than others, and propagation and your distance from the various stations means that some will be received better at your location than others.