According to the notes of
The Conet Project, which has compiled recordings of these transmissions, number stations have been reported since with the numbers transmitted in Morse code. 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. Numbers stations were most abundant during the
Cold War era. According to an internal Cold War-era report of the Polish Ministry of the Interior, numbers stations DCF37 (3.370 MHz) and DFD21 (4.010 MHz) were transmitted from
West Germany beginning in the early 1950s. Many stations from this era 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. In rare cases,
shortwave listeners who sent reception reports to stations that identified themselves received
QSL responses, an unusual occurrence for a clandestine operation. 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.
Atención spy case The "Atención" station of Cuba became the world's first numbers station to be officially and publicly accused of transmitting to spies. It was the centerpiece of a United States federal court espionage trial, following the arrest of the
Wasp Network of Cuban spies in 1998. The U.S. prosecutors claimed the accused were writing down number codes received from Atención, using Sony hand-held shortwave receivers, and typing the numbers into
laptop computers to decode spying instructions. The FBI testified that they had entered a spy's apartment in 1995, and copied the computer decryption program for the Atención numbers code. They used it to decode Atención spy messages, which the prosecutors unveiled in court. stated that "defendants would receive assignments via shortwave radio transmissions". In June 2009, the United States similarly charged
Walter Kendall Myers with conspiracy to spy for Cuba, and receiving and decoding messages broadcast from a numbers station operated by the Cuban Intelligence Directorate to further that conspiracy. As discovered by the FBI up to 2010, one way that Russian agents of the
Illegals Program were receiving instructions was via coded messages on shortwave radio.
North Korea revived number broadcasts in July 2016 after a hiatus of sixteen years, a move which some analysts speculated was
psychological war; sixteen such broadcasts occurred in 2017, including unusually timed transmissions in April. In late February 2026, coinciding with the outbreak of the
2026 Iran war and subsequent
internet blackouts, a new
Farsi-language numbers station began broadcasting on 7910
kHz (
USB). The station, designated V32 by the
ENIGMA 2000 monitoring group on March 3, 2026, features a male voice reading structured numeric groups in Farsi, frequently repeating the word "Tavajjoh" (Persian for "Attention"). == Suspected use for espionage ==