By the Numbers

Communications in Espionage

Grimy Miner, Going Postal

On Going Postal we have a number of radio hams (holders of the Amateur Radio Broadcast Licence), and lots of others who have radio equipment with that tantalising logo on the tuning dial “SW”.

SW stands for Short Wave – that is, frequencies within the range of 3 MHz to 30MHz (a wavelength of 100metres to 10metres) – as the frequency increases the wavelength decreases.

Short wave is useful because, unlike AM and FM it can be received from a great distance away, it is not confined to just line of sight or little more. It uses a phenomenon called “skywave” which bounces radio waves, of the right wavelength, off the ionosphere.

Grimy Miner, Going Postal

This skywave can travel around the Earth many times and give almost universal coverage (the lack of Sunspots mentioned by some posters in the BTL comments as being responsible for some climate anomalies also affects short wave radio broadcasts, restricting the range of such broadcasts).

Usually most people listen to the FM or AM station of choice, or to a station that only broadcasts on the internet.

However, there is a band of listeners, and broadcasters, who tune into the shortwave bands. These shortwave listeners encounter a world of mostly international radio stations broadcasting from countries like China, Cuba, Iran, or Romania. These frequencies also include amateur radio and marine and air traffic.

Grimy Miner, Going Postal

Sooner or later, however, those who listen to these more off-beat wavebands will stumble across strange broadcasts repeating number groups in digitally synthesized voices. Sometimes they are read live, sometimes in Morse code, and sometimes by means of digital noise transmission.

These are the so-called numbers stations

Grimy Miner, Going Postal

Numbers stations have been in existence since World War I. Over the years they have attracted sporadic interest from journalists, video game designers, and filmmakers. (see the film, The Numbers Station)

Despite this attention, there are few explanations of what these signals actually are. Too often, they are described as spooky, creepy, or mysterious, and the discussion stops there. It may be disappointing to some, but these stations are not signals from aliens or mind control devices, nor are they dead relics of the Cold War — rather, these stations are part of the sophisticated work of intelligence agencies and militaries, and they are very much still on the air. This article will explain what they are, how to listen to them, and why they matter.

First of all, you will need a radio that tunes into the short wavebands – these radios used to be commonplace when radios were “steam driven”, but these days usually only sophisticated radios have the capability to tune these bands.

Grimy Miner, Going Postal

Then, all you have to do is tune through the wavebands and, if you are lucky, you will chance on one of these “Numbers Stations”

Here are a few sound recordings of the most common ones

OK, they ARE creepy and mysterious, but what actually are they?

To date, no-one has owned up to making any of these broadcasts. They have been going on for more than 30 years

They do this day and night on a wide range of frequencies and it’s been going on for decades, yet no single private, commercial or government agency ever stepped forward to officially confirm that they are responsible for these strange broadcasts of numbers. However, today there is enough evidence that Intelligence agencies use these numbers stations, also called one-way voice link, to send encrypted operational messages and instructions to their agents in covert operations abroad.

The numbers or letters are spoken in many different languages, usually a female voice, but sometimes male or those of children. Many of the broadcasts are mysterious mechanically or electronically generated voices. The stations often use introduction signals as a beacon, prior to a actual message. These repeating phrases, electronic sounds or music enable the receiver to adjust his radio to the desired frequency. In recent years, many numbers stations switched from voice or Morse to digital tones.

Radio amateurs monitor these broadcasts and they sometimes give nicknames to a station, according to its typical introduction music, (Swedish rhapsody or The Lincolnshire Poacher) or language of the voice (Bulgarian Betty). Some stations are called counting stations, because of their introduction signal. An example is the Cuban “Atencion 1234567890”.

Most numbers stations use a basic format to send the streams of numbers or letters. Some stations broadcast every day at a fixed hour, and disappear after a few days or weeks. Other stations have an irregular time schedules and appear and disappear over time. One of the most regular numbers stations ever was the Lincolnshire Poacher (E3 Voice), named after the English folk song that was used as its interval signal. After transmitting the very recognizable melody and a call-sign for about ten minutes, the message was sent by an electronic English-accented female voice in groups of five figures. The station aired every day from the 1970s until 2008. A simple small shortwave radio was sufficient to capture the Lincolnshire Poacher. It is believed that the station broadcast from the RAF Akrotiri basis in Cyprus and that is was operated by the British Secret Intelligence Service. Unfortunately, the world of radio waves lost a true Cold War icon when the station went off-air in 2008. Its Asian sister station Cherry Ripe however is still active.

So, these numbers are being broadcast, regularly and at a fixed time, usually on the hour at night.

We don’t really know who is sending these numbers so who are the recipients of these broadcasts?

Although no government or legal broadcaster ever acknowledged any involvement in these broadcasts, it is obvious that the costs and organization of such large-scale illegal broadcasts can only be supported and approved by government agencies. Countries like Russia, China and the United States exploit large shortwave antenna parks in their own country and at their embassies abroad.

The content of the messages appear to be a random series of numbers without any logical order or meaning. It is confirmed in several uncovered spy cases that these seemingly random numbers are actually one-time-pad encrypted messages. Numbers messages were used extensively during the Second World War. The British Special Operations Executive (SOE), the American Office of Strategic Services (OSS) and many other wartime intelligence agencies used them to communicate with their espionage and sabotage teams, operating behind enemy lines.

Grimy Miner, Going Postal

History has proven this to be a most secure method. One-time pads are sheets or booklets with keys that consist of series of truly random numbers or letters. Enciphering and deciphering a message only requires pencil and paper and some basic calculations. Each message is enciphered with a unique one-time pad which is destroyed after one-time use. If properly applied, one-time pad is the only system that is proven to be mathematically unbreakable.

I will end this article at this point and explore the use of the One Time Pad in the next article.

© Grimy Miner 2019

The Goodnight Vienna Audio file