The most famous numbers stations

Enthusiasts often gave numbers stations names, usually derived from some permanent element of their broadcasts. For example, the now-defunct station "Lincolnshire Poacher" (according to researchers, sponsored by the British government agency MI6 – the station broadcast from a British military base in Cyprus) always played the folk tune "The Lincolnshire Poacher" at the beginning of its transmissions; the station "Magnetic Fields" played music by Jean Michel Jarre at the beginning and end of its broadcasts; and "Atención" began its broadcasts with the Spanish word "Atención."

Although attempts to locate and pinpoint the source of numbers stations can be quite time-consuming, it is sometimes possible to determine the origin of a given station based on an error made by the broadcasters. Such a mistake was made by the broadcaster "Atención" – a few years ago, the station mistakenly "jammed" onto the frequency of Cuban Radio Havana. Thanks to this, in 2000, the US military was able to identify "Atención" as a station broadcasting from Cuba.

The American magazine "Popular Communications" published several articles in the 1980s and 1990s in which hobbyists described portable equipment they used to locate numbers stations broadcasting in Florida and Warrenton, Virginia. In several cases, radio amateurs managed to spot small transmitters hidden inside military equipment. The devices were connected to telephone lines via cable. The author of the "Popular Communications" articles wrote that the Federal Communications Commission never responded to any of the inquiries about numbers stations.

With some numbers stations, background tones can be heard. Some researchers suggest that in such cases, a human voice could be used to help tune the receiver to the appropriate frequency. A coded message could then be transmitted using modulated tones. This technology could be similar to packet transmission.