Number stations

If you have a shortwave radio with continuous tuning then you have the ability to listen to frequencies between the standard broadcast and amateur radio bands.

Whilst listening between the regular bands you may sometimes hear something a little odd. Perhaps you will hear a female with a slightly mechanical voice. Instead of reading the news or introducing a piece of music all you will hear from this sultry maiden are numbers or NATO call signs (alpha, bravo, charlie etc).

If you listen over many weeks you will realise there are schedules, set frequencies and a certain style in the reading of the numbers and call signs. You will notice that the voice is emotionless and never falters.

These broadcasts are from Number Stations and they have been broadcasting for decades. Number stations are government security departments sending messages to spies out in the field. The messages are generated electronically hence the monotone voices. There is no lady reading from a script.

You will ask, "Why use an 'old fashioned' technology like shortwave broadcasts when everyone uses the Internet to send messages?" Well, the drawback with the Internet is that you have to go online to read an e-mail and, as soon as you do go online, counter-espionage forces will know exactly where you are. With a shortwave broadcast nobody knows to whom the message is for. The spy may be anywhere within range of the transmitter.

The spy can use a tiny receiver, especially made for the task, to listen to the message. The message is encoded using an unbreakable one-time pad, which uses a never-ending random encryption algorithm that can never be broken. Only the spy in the field can decode the message with his copy of the one-time pad. Number stations offer a clean and efficient way to send messages to spies.

One transmitter has been traced to a British military base on the island of Cyprus. It is believed to be sending messages to people spying for British intelligence in the Middle East. The Lincolnshire Poacher, as the number station is known, broadcasts a piece from the folk song The Lincolnshire Poacher to alert spies that a message is imminent. A message is then sent in groups of five numbers.

Another spy service run by Israel's Mossad sends NATO call-signs in groups of five NATO call-signs to its agents. In Cuba, Spanish messages are sent to spies in the US, Carribean, Central and South America.

If you want to listen to Number Stations then any shortwave radio with continuous tuning and SSB will pick up messages. Don't expect to decode the messages as one-time pads are the only truly unbreakable encryption methods. Number station listening is a hobby in itself and there are a band of dedicated listeners logging messages, transmitter locations and regularity of messages during times of strife.

Why listen to shortwave?

I get asked this question quite frequently. People tell me that I can listen to any station in the world online. That's not true, there are many stations that are not online. And what if the Internet fails one day? It takes a lot of energy and technology to run the Internet that might not be around in the future. Who knows.

I do listen to radio on the Internet but I enjoy being able to turn the tuning knob and happen upon a programme by accident. You can't do that online, you have to know what you are looking and then type in an address. There is excitement from finding something new online.

There is a lot more going on in shortwave. You can listen in as radio hams talk about everyday things, something you can't do online unless you are invited into an online chat. You can listen to the strange world of espionage through number stations and listen to their lists of numbers and call-signs. There are people sending fax and teletype messages. Diplomats sending encrypted messages. Weather stations sending reports. You can practice learning a new language. Many stations have language lessons. There is a lot going on in the shortwave and it is a joy to happen upon it during an evening.

Shortwave equipment is a lot more approachable, a lot more simple and a lot cheaper than computing equipment. You are reliant on yourself and can make a lot of equipment yourself. With a computer you are dependent on others to connect you to the Internet. In many countries, governments restrict access to the Internet but can't jam every of shortwave band.

In areas of the world where computers and the Internet have not reached you can be sure there is a shortwave radio. There will be a need for shortwave for many years to come.

DX Report - May 9th 2008

19:30 / Radio Kuwait / Kuwait City, Kuwait / 11990 / English / History of Art

19:40 / Voice of Nigeria / Lagos, Nigeria / 15120 / English / Nigerian popular music

Grundig Satellit 500

My own receiver is a Grundig Satellit 500, which was produced from 1989-1991. Though it was improved upon by later models I find it more than adequate for listening to shortwave broadcasts.

There are a few variants to the model. If you buy one then make sure it is the international version with full coverage from 1612-30000 KHz. The radio also covers LW, MW and FM. There is also an SSB mode for listening to those broadcasts using it.

The radio comes with a continuous digital tuner so that all amateur and utility bands are covered. Frequencies can either be entered on a keypad or an analogue style knob can be rotated for rapidly scanning through a band. An LCD readout tells you exactly which frequency you are tuned to. There is a memory function for storing up to 42 frequencies.

There is a switch to chose between the telescoping aerial inside the radio or an external antenna. I made my own antenna, which is permanently connected to the radio.

Though the radio is no longer manufactured, fine examples are often sold on eBay. Expect to pay about £80 ($160), which will give you a cheaper and better radio than many of the new shortwave radios that have lesser capabilities.

Shortwave listening equipment

As with any hobby, you can spend as little or as much as you want. Needless to say, the more you spend on shortwave equipment the more you will hear. However, even with quite modest equipment from second-hand sources you can get good results.

Here is my set-up, all of which was either bought second-hand on eBay or made by myself.

The radio is a Grundig Satellit 500 bought on eBay for less than £80. It's most important feature is the digital tuner. You can get cheaper radios with analogue dials. The problem with an analogue dial is that you have no idea what the exact frequency is.

If you want to be able to be able to log your listening sessions and revisit favourite stations then you will need a digital tuner with an LCD readout.

Shortwave can be heard on frequencies between 1612 and 30000 KHz. A radio with continuous tuning between those frequencies is desirable so that all bands, including amateur and utility bands can be received. Also, you will need Single Side Band (SSB) capabilities for those broadcasting (usually Radio Hams) on this variation of AM broadcasting.

This is an example of a cheap radio with an analogue tuner. There is no continuous tuning through the shortwave bands so you can't receive any utility or amateur signals. Even if you could pick up amateur signals they would be unintelligible because there is no SSB mode. I bought this radio because I knew to see if shortwave listening was for me. It was £30 ($60) not well spent. Still, it is fine for packing a small FM receiver for camping.

These two pieces of equipment are not essential but enhance your shortwave listening greatly. The lowermost is an antenna tuner. I built it myself from plans I found on the Internet. It cost me about £30 to buy the parts, some of which were bought second-hand on eBay. A tuner helps you to get the most from your antenna.

Sitting on top of the tuner is a digital signal processor (DSP). If a signal is very weak or there is a lot of interference then it will be hard to understand what you are hearing. The DSP provides various filters for removing noise.

My antenna is an indoor loop, made from a 25-feet long piece of telephone cable. The cable consists of the usual four cores. By using a terminal block I linked each of the four cores together to create a 100-feet long loop. Look carefully at the terminal block and you will see that the black wire is joined to the red wire, which is connected to the green wire, which is connected to the yellow wire. The light green wire at top right leads to my antenna tuner.

What is shortwave radio?

Shortwave radio was so-called during the early days of radio because the wavelengths used were shorter than the prevalent longer wavelengths used at the time. Such wavelengths can travel much further than FM, MW and LW by bouncing off the ionosphere.
This permits the listener to pick up radio stations beyond the horizon and from across the globe.

Shortwave radio is used for international broadcasting with many governments using it as a way of putting forward their view on world affairs. Amateurs or Radio Hams can often be heard chatting on wavebands reserved for amateur use. There are utility stations broadcasting weather reports and coded diplomatic messages between embassies. Number stations can also be heard on shortwave. These stations broadcast numbers or NATO call-signs at regular points during the day and are believed to be coded messages broadcast to spies on active service in foreign lands.

Shortwave radio can be heard on frequencies between 1612 and 30000 KHz. A radio with continuous tuning between those frequencies is desirable so that all bands, including amateur and utility bands can be received. Also, you will need Single Side Band (SSB) capabilities for those broadcasting (usually Radio Hams) on this variation of AM broadcasting.