A numbers station is a shortwave radio station characterized by broadcasts of formatted numbers, which are believed to be addressed to intelligence officers operating in foreign countries. Most identified stations use speech synthesis to vocalize numbers, although digital modes such as phase-shift keying and frequency-shift keying, as well as Morse code transmissions, are not uncommon. Most stations have set time schedules, or schedule patterns; however, other stations appear to have no discernible pattern and broadcast at unpredictable times. Stations may or may not have set frequencies in the high frequency band. The first known use of numbers stations was during World War I, with the numbers transmitted in Morse code. Numbers stations were most prolific during the Cold War era, yet many continue to broadcast and some long-time stations may have been taken over by different operators. The Czech Ministry of the Interior and the Swedish Security Service have both acknowledged the use of numbers stations by Czechoslovakia for espionage, with declassified documents proving the same. Few QSL responses have been received from numbers stations by shortwave listeners who sent reception reports to stations that identified themselves or to entities the listeners believed responsible for the broadcasts, which is the expected behaviour of a non-clandestine station. One well-known numbers station was the E03 “Lincolnshire Poacher”, which is thought to have been run by the British Secret Intelligence Service. It was first broadcast from Bletchley Park in the mid-1970s but later was broadcast from RAF Akrotiri in Cyprus. It ceased broadcasting in 2008. In 2001, the United States tried the Cuban Five on the charge of spying for Cuba. The group had received and decoded messages that had been broadcast from the “Atención” number station in Cuba. Monitoring and chronicling transmissions from numbers stations has become a hobby for shortwave and ham radio enthusiasts dating from the 1970s, though it is reported that Archduke Anton of Austria in his youth during World War I used to listen in to their transmissions, writing them down and passing them on to the Austrian military intelligence.
Appearance List Book: Secret Signals: The Euronumbers Mystery (1988) by Simon Mason — one of the earliest systematic hobbyist studies of numbers stations. Podcast: Astonishing Legends: Episode 240 Numbers Stations
Description A numbers station is a shortwave radio station characterized by broadcasts of formatted numbers, which are believed to be addressed to intelligence officers operating in foreign countries. Most identified stations use speech synthesis to vocalize numbers, although digital modes such as phase-shift keying and frequency-shift keying, as well as Morse code transmissions, are not uncommon. Most stations have set time schedules, or schedule patterns; however, other stations appear to have no discernible pattern and broadcast at unpredictable times. Stations may or may not have set frequencies in the high frequency band. The first known use of numbers stations was during World War I, with the numbers transmitted in Morse code. Numbers stations were most prolific during the Cold War era, yet many continue to broadcast and some long-time stations may have been taken over by different operators. The Czech Ministry of the Interior and the Swedish Security Service have both acknowledged the use of numbers stations by Czechoslovakia for espionage, with declassified documents proving the same. Few QSL responses have been received from numbers stations by shortwave listeners who sent reception reports to stations that identified themselves or to entities the listeners believed responsible for the broadcasts, which is the expected behaviour of a non-clandestine station. One well-known numbers station was the E03 “Lincolnshire Poacher”, which is thought to have been run by the British Secret Intelligence Service. It was first broadcast from Bletchley Park in the mid-1970s but later was broadcast from RAF Akrotiri in Cyprus. It ceased broadcasting in 2008. In 2001, the United States tried the Cuban Five on the charge of spying for Cuba. The group had received and decoded messages that had been broadcast from the “Atención” number station in Cuba. Monitoring and chronicling transmissions from numbers stations has become a hobby for shortwave and ham radio enthusiasts dating from the 1970s, though it is reported that Archduke Anton of Austria in his youth during World War I used to listen in to their transmissions, writing them down and passing them on to the Austrian military intelligence.
