Numbers Stations

Numbers Stations Deze pagina in het Nederlands

Numbers stations are mysterious shortwave radio stations, broadcasting streams of numbers or letters using the phonetic alphabet, by voice or Morse signals. Although the source of these broadcasts is unknown, there is no doubt that they are used by government agencies to send encrypted messages to secret agents in covert operations.

Numbers in the air

Most of these numbers stations use a basic format to send the streams of numbers or letters. Some stations start broadcasting every day on a fixed hour, and disappear after a few days or weeks, others have irregular time schedules and appear and disappear over time. The messages are broadcasted on very powerful shortwave transmitters with frequencies ranging from 3,000 to 30,000 Khz and are received all over the world.

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-generated voices. The messages are usually groups of four or five numbers or letters and are typically repeated by reading each group twice or repeating the entire message. Introduction signals are used as a beacon, prior to a message. These are repeating phrases or musical or electronic sounds, enabling the receiver to adjust his radio to the desired frequency. Radio amateurs monitor these broadcasts and they sometimes give nicknames to stations, according to the introduction phrase (e.g. DFD21 or the Cuban "Atencion" station) or the prelude music (e.g. Swedish rhapsody). Some stations are called counting stations, because of their introduction signal. An example is the Cuban "Atencion 1234567890".

There were more numbers stations in the period of the Cold War. Many of the broadcasts came from the Eastern-block countries, Cuba and South-America. After the fall of the Berlin Wall the number of stations significantly decreased from countries like East-Germany, Yugoslavia, or Hungary. Most of these voices were Russian or German. However, there are still numbers stations active in the former Soviet-Union, Europe and even North and South America, and new stations continue to appear.

Evidence for use as Spy Stations

Numbers stations are a secure way to communicate with secret agents in the field and the letters or numbers are encrypted messages. These stations are unlicensed high power HF transmitters, broadcasting worldwide in various formats and languages. They do this day and night on a wide range of frequencies and it's been going on for decades. No single private, commercial or government agency has ever stepped forward to simply explain these transmissions. However, the costs and organisation of such large-scale illegal broadcasts can only be supported or approved by government agencies. Also, it is publicly known that embassies and intelligence services of countries like the United States or Russia have large shortwave antenna parks. Although no government or legal broadcaster has acknowledged the existence of numbers stations or admitted any involvement with these stations, there is enough evidence that shows clearly that these stations are indeed used by intelligence services to transmit secret messages:

The content and structure of the messages are identical to cryptographically encrypted messages. The groups appear to be totally random and without any logical order or meaning. It is assumed that a one-time-pad encryption is used. One-time-pad is a system where the message is encrypted with a unique key. The key is only used once and has the same length as the message. One-time-pad is the only system, proven mathematically unbreakable if properly used. Secret agents can carry a large number of one-time-pads keys on small booklets or microfilm and although the one-time-pad method is slow and elaborate, it requires only pencil and paper to decipher a messages.

Spies have been caught in possession of shortwave radios and one time pads. In 1988 Vaclav Jelinek, a Czech StB spy who operated under the false identity of Erwin van Haarlem, was arrested by British Special Branch detectives while receiving a numbers message on a shortwave radio in his London apartment. One-time pads were found on microfilm, hidden in bars of soap. The pads enabled the detectives to decipher some of the received messages, which were later used in court. Jelinek was sentenced to ten years of imprisonment. Documents of the East German Ministerium fur Staatssicherheit, the Stasi, describe in detail intercepted packets, destined for German CIA agents that lived in the former DDR, with one-time pads, instructions on how to receive numbers messages on shortwave radio and the deciphering procedures for these messages. These ar published on the SAS und Chiffrierdienst website. Michael Michnowski defected together with Stasi agent Werner Stiller from East Germany in 1979. He published his story about the preparations and the defection. In that story he describes the covert communications with the Bundes Nachrichten Dienst, West-German intelligence, and how they used a shortwave radio to receive one-time pad encrypted instructions, sent by BND numbers stations. A video of a device, used by the Stasi, to convert numbers into voice or morse, is available on this page.

More recently, there were several spy cases in the United States, related to Cuban numbers stations . In the 1998, the so-called Cuban Five from the Wasp Network spy ring, agents of the Cuban DGI (Dirección General de Inteligencia), received instructions by encrypted messages that were sent each day by the Cuban HF numbers station "Atencion". Another one was the Ana Belen Montes case, a senior US Defense Intelligence Agency analyst, spying for Cuba. She was arrested in 2001 and the federal prosecutors stated: "Montes communicated with the Cuban Intelligence Service through encrypted messages and received her instructions through encrypted shortwave transmissions from Cuba". More on the Belen Montes case in this FBI affidavit (pdf) and the Court Indictment (CI Centre pdf). Carlos Alvarez, a Florida International University professor was arrested in 2006 on spying for Cuban Intelligence. He also used a shortwave radio to receive five-digit numbers messages which were decrypted using computer disks. US State Department official Walter Kendall Myers and his wife Gwendolyn Steingraber Myers were arrested in 2009 on charges of serving as illegal agents of the Cuban government for nearly 30 years. They acknowledged having received encrypted messages from the Cuban Intelligence via a shortwave radio they possessed. The Columbia State District Court indictment stated that "Cuban intelligence broadcasts encrypted shortwave radio messages in Morse Code or by a voice reading numbers" and also that "It was part of the conspiracy that Cuban Intelligence would and did broadcast shortwave messages in Morse Code which were receive by Kendall Myers". More about this case on CI Centre and the zip file with court indictment and FBI reports.

And still, every day, numbers messages are transmitted all over the world, spoken in English, Russian, Spanish, Chinese and many other languages. Who's listening to them?

Why Numbers Stations

The method of broadcasting has many advantages to intelligence services. Shortwave transmitters reflect their signal many times between the earth surface and the ionosphere, carrying them over very long distances. This enables them to send messages to far away located agents in foreign countries. Because of the many reflections of shortwave signals it is much harder to locate the transmitter. As it is impossible to find out who is sending the message and because it's unknown who receives the message it is an ideal way to communicate in a secure way with secret agents without taking any risks. The agent doesn't need any special equipment to receive or decipher a message since anyone with a simple commercial shortwave world-receiver can pick up these messages and decipher them with pencil and paper. This avoids being caught with compromising communications equipment.

Are numbers stations still useful in this age of global communications, Internet and satellite links? Yes! All modern communication systems are controlled by computers. Telephone, Internet and even satellite transmissions can be monitored. E-mails can be intercepted and read. Government agencies have the money and resources to monitor communications and trace sender and receiver. An example is the hugh ECHELON project which globally intercepts all kinds of communications. In times of conflict, countries can simply block all Internet or other data traffic, or even simply switch off satellites. Also, there have been several successful test to destroy satellites with missiles. Or do you really believe you could continue to telephone or chat over the Internet during a serious conflict between, let's say, Russia and the United States? Imagine a war broke out and intelligence personnel is operating behind enemy lines. The only way to communicate with them would be the good old-fashion long distance Short Wave radio. And most important, no one can tell who is receiving these broadcastings. But even in times of peace some covert operations are so sensitive that discovering them would bring governments or countries in big problems. It is believed that some numbers stations continuously send fake messages, just to keep the lines active, ready for use when required. Those who monitor these stations are unable to notice when a station suddenly starts sending operational coded traffic instead of random garbage. A good example of this is the Lincolnshire Poacher, sending messages of exactly 200 groups, every single day since the 1970's. So, reasons enough why numbers stations are still useful and active.

Listen to the Lincolnshire Poacher yourself

One of the most regular numbers stations is the Lincolnshire Poacher (classification E3 Voice), named after the English folk song that is used as interval signal. The station is in the air since the 1970's. A small shortwave radio is sufficient to capture the Lincolnshire Poacher. You may need to try out different frequencies, locations and directions for good reception. A five meter long electric wire, connected to the antenna, can be useful to boost the signal. Evening hours will give more interferences, but the signal often travels longer distances. Here in central Europe I have the best results at 17.00 and 18.00 UTC on 6.959 and 12.603 Mhz (last check June 2008). The station transmits from the RAF Akrotiri basis in Cyprus and is believed to be operated by the British Secret Intelligence Service . It broadcasts each day on fixed hours and starts by repeating the melody and a call-sign for about ten minutes. Next, the message is sent by an electronic English-accented female voice in groups of five figures. At the bottom of this page there's a Lincolnshire Poacher recording with its very recognizable melody. Most recent info on the Lincolnshire Poacher on Simon Mason's website or SpyNumbers.com.

The Lincolnshire Poacher is off-air! Help tracking him again. After decades of broadcasting, the station is last heard end June 2008. Whether the station will return and continue its broadcasting is unknown. Its Asian sister station Cherry Ripe is still active. More here. Any change in its status will be posted here. Did you capture the Lincolnshire Poacher again on the old or some new frequencies, please e-mail me!

Broadcast schedule: each hour from 12.00 until 22.00 Hr. UTC.

Currently used frequencies in Khz: 5422 - 5746 - 6485 - 6900 - 6959 - 7337 - 7755 - 8464 - 9251 - 10426 - 11545 - 12603 - 13375 - 14487 - 15682 - 16084

Some recordings

Lincolnshire Poacher (1724 Kb) English female voice, MI6, introduced by a melody
Swedish Rhapsody Child (188 Kb) This is a mechanical child voice, introduced by an 'ice cream man' melody
Yankee Bravo (131 Kb) German female voice, probably of KGB origin, introduced by the call sign YB
Russian Male (83 Kb) Russian male voice, KGB

Right-click the icon and select 'save target as' to download the mp3 file.

Numbers on the Internet

Numbers messages can also be distributed through the Internet. The Numbers Relay Page (NRP) is an online method to post numbers messages. The NRP is an easy way to exchange encrypted messages without disclosing the sender or receiver and requires only a computer with Internet browser. More about the NRP on this page.