Numbers station
Encyclopedia
A numbers station is a shortwave
radio station of uncertain origin. In the 1950s, Time magazine reported that the numbers stations first appeared shortly after World War II
and were using a format that had been used to send weather data during that war.
Numbers stations generally broadcast artificially generated voices
reading streams of numbers, words, letters (sometimes using a spelling alphabet
), tunes or Morse code
. They are in a wide variety of languages and the voices are usually female, although sometimes men's or children's voices are used.
Evidence supports popular assumptions that the broadcasts are used to send messages to spies
. This usage has not been publicly acknowledged by any government that may operate a numbers station, although two QSL
s have been received from numbers stations by shortwave listeners
who sent reception reports to said stations, which is the expected behaviour of a non-clandestine station.
In 2001, the United States tried the Cuban Five on the charge of spying for Cuba. That group had received and decoded messages that had been broadcast from a Cuban numbers station. Also in 2001, Ana Belen Montes, a senior US Defense Intelligence Agency
analyst, was arrested and charged with espionage. The federal prosecutors stated: "Montes communicated with the Cuban Intelligence Service through encrypted messages and received her instructions through encrypted shortwave transmissions from Cuba." In 2006, Carlos Alvarez
and his wife, Elsa
, were arrested and charged with espionage. The U. S. District Court
Florida stated: "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 Service to further that conspiracy.
It has been reported that the United States uses numbers stations to communicate encoded information to persons in other countries. The State Department operated several stations, such as KKN50, that broadcast similar "numbers" messages.
, which has compiled recordings of these transmissions, numbers stations have been reported since World War I
. If accurate, this would make numbers stations among the earliest radio broadcasts.
It has long been speculated, and was argued in court in one case, that these stations operate as a simple and foolproof method for government agencies to communicate with spies
working undercover. According to this theory, the messages are encrypted with a one-time pad
, to avoid any risk of decryption by the enemy. As evidence, numbers stations have changed details of their broadcasts or produced special, nonscheduled broadcasts coincident with extraordinary political events, such as the August Coup
of 1991 in the Soviet Union.
Number Stations are also acknowledged for espionage purposes in Robert Wallace and H. Keith Melton's Spycraft (p. 438):
Others speculate that some of these stations may be related to illegal drug smuggling
operations. Unlike government stations, smugglers' stations would need to be lower powered and irregularly operated, to avoid location by triangulated direction finding
, followed by government raids. However, numbers stations have transmitted with impunity for decades, so they are generally presumed to be operated or sponsored only by governments. Also, numbers station transmissions in the international shortwave bands typically transmit high power levels that might be unavailable to ranches, farms, or plantations in isolated drug-growing regions. However, if the intended recipient has the space for an outdoor long wire antenna, and can afford to wait to the correct time of day for propagation to 'open' then the transmitter power requirement would be modest, a few tens of watts .
High frequency
radio signals transmitted at relatively low power can travel around the world under ideal propagation
conditions, which are affected by local RF noise
levels, weather, season, and sunspots, and can then be received with a properly tuned antenna of adequate size, and a good receiver. However, spies often have to work only with available hand held receivers, sometimes under difficult local conditions, and in all seasons and sunspot cycles. Only very large transmitters, perhaps up to 500,000 watts, are guaranteed to get through to nearly any basement-dwelling spy, nearly any place on earth, nearly all of the time. Some governments may not need a numbers station with global coverage if they only send spies to nearby countries.
Although no broadcaster or government has acknowledged transmitting the numbers, a 1998 article in The Daily Telegraph quoted a spokesperson for the Department of Trade and Industry (the government department that, at that time, regulated radio broadcasting in the United Kingdom
) as saying, "These [numbers stations] are what you suppose they are. People shouldn't be mystified by them. They are not for, shall we say, public consumption."
On some stations, tones can be heard in the background. It has been suggested that in such cases the voice may be an aid to tuning to the correct frequency, with the coded message being sent by modulating
the tones, perhaps using a technology such as burst transmission
.
The use of number stations as a method of espionage is discussed in Spycraft (p. 37):
. For example, the "Lincolnshire Poacher
", formerly one of the best known numbers stations (generally thought to be run by SIS
, as its transmissions have been traced to RAF Akrotiri
in Cyprus
), played the first two bars of the folk song "The Lincolnshire Poacher
" before each string of numbers. "Magnetic Fields" plays music from French electronic music
ian Jean Michel Jarre
before and after each set of numbers. The "Atención" station begins its transmission with the Spanish
word "¡Atención!"
Although it is time-consuming and may require costly global travel to pinpoint the source of a radio transmission in the shortwave band, errors at the transmission site, radio direction-finding, and a knowledge of shortwave radio propagation have provided armchair detective
s clues to some number station locations.
For example, the "Atención" station was thought to be from Cuba
, as a supposed error allowed Radio Habana Cuba to be carried on the frequency. Whether the frequency of Radio Habana Cuba and the frequency of the "Atención" station merely interfered with each other or whether the operator of the station was listening to the radio and it accidentally ended up on the air is unclear.
Also, several articles in the radio magazine Popular Communications
published in the 1980s and early 1990s described hobbyists using portable radio direction-finding equipment to locate numbers stations in Florida and in the Warrenton
, Virginia
, areas of the United States. From the outside, they spotted the station's antenna inside a military facility. The station hunter speculated that the antenna's transmitter at the facility was connected by a telephone wire pair to a source of spoken numbers in the Washington, D.C.
, area. The author said the Federal Communications Commission
would not comment on public inquiries about American territory numbers stations.
United States government evidence included the following three examples of decoded Atención messages. (Not reported whether the original clear texts were in Spanish, although the phrasing of "Day of the Woman" would indicate so.):
At the rate of one spoken number per character per second, each of these sentences takes a minute or more to transmit.
The moderator of an e-mail list for global numbers station hobbyists claimed "Someone on the Spooks list had already cracked the code for a repeated transmission [from Havana to Miami] if it was received garbled." Such code-breaking is possible if a one-time pad
decoding key is used more than once.
The prelude or introduction of a transmission (from which stations' informal nicknames are often derived) includes some kind of identifier, either for the station itself and/or for the intended recipient. This can take the form of numeric or radio-alphabet "code names" (e.g. "Charlie India Oscar", "250 250 250"), characteristic phrases (e.g. "¡Atención!", "1234567890"), and sometimes musical or electronic sounds (e.g. "The Lincolnshire Poacher", "Magnetic Fields"). Sometimes, as in the case of the Israel
i radio-alphabet stations, the prelude can also signify the nature or priority of the message to follow (e.g.(hypothetically) "Charlie India Oscar-2", indicating that no message follows). Often the prelude repeats for a period before the body of the message begins.
There is usually an announcement of the number of number-groups in the message, then the groups are recited. Groups are usually either four or five digits or radio-alphabet letters. The groups are typically repeated, either by reading each group twice, or by repeating the entire message as a whole.
Some stations send more than one message during a transmission. In this case, some or all of the above process is repeated, with different contents.
Finally, after all the messages have been sent, the station will sign off in some characteristic fashion. Usually it will simply be some form of the word "end" in whatever language the station uses (e.g. "end of message, end of transmission"; "Ende"; "fini"; "final"; "конец"). Some stations, especially those thought to originate from the former Soviet Union
, end with a series of zeros, e.g. "000 000"; others end with music or other sundry sounds.
Because of the secretive nature of the messages, the cryptographic function
employed by particular stations is not publicly known, except in one or possibly two cases. It is assumed that most stations use a one-time pad
that would make the contents of these number groups indistinguishable from randomly generated numbers or digits. In one definitely known case, West Germany did use a one-time pad for numbers transmissions.
s using powers from 10 kW to 100 kW.
Amplitude modulated
(AM) transmitters with optionally variable frequency, using class-C power output stages with plate modulation, are the workhorses of international shortwave broadcasting, including numbers stations.
Application of spectrum analysis
to number station signals has revealed the presence of data bursts, RTTY
-modulated subcarrier
s, phase-shifted carriers
, and other unusual transmitter modulations like polytones
. (RTTY-modulated subcarriers were also present on some U.S. commercial radio transmissions during the Cold War.)
The frequently reported use of high tech modulations like data bursts
, in combination or sequence with spoken numbers, suggest transmissions for differing intelligence operations.
For spies in the field, low tech spoken number transmissions continue to have advantages in the 21st century. High tech data receiving equipment is difficult to obtain, and being caught with more than a civilian shortwave news radio could be construed as evidence of spying. Yet governments' embassies, aircraft, and ships at sea are known to possess complex receiving equipment that could make regular use of encrypted data transmissions from the home country. These probably include charts and photos that require more transmitted data than can be sent efficiently using spoken numbers.
there was substantial evidence from the amateur radio community that the USSR may have been using transmitters to reach agents in Western Europe, North Africa, and possibly North America with output power ranging up to 500 kW. HF
direction finding evidence that was collected by many different sets of amateurs in Europe, Africa, and the Americas during the Cold War substantiates number stations broadcasting from the East of the Urals
.
USSR technical literature shows that the USSR pioneered HRS 8/8/1 directional HF antennas for shortwave news and information broadcasting in the late 1960s–mid 1970s. Thus it is possible that lower transmitter powers (like 100 kW) were used in the 1980s (late Cold War) for numbers station use.
n foreign language service Voice of Korea
began to broadcast on the Lincolnshire Poacher's
former frequency, 11545 kHz, in 2006, possibly to deliberately interfere with its propagation. This clash can be viewed in video format. The apparent target zone for the Lincolnshire Poacher signals originating in Cyprus was the Middle East
, not the Far East
which is covered by its sister station Cherry Ripe
.
On 27 September 2006, amateur radio transmissions in the 30 m band were affected by an E7 "Russian Man" number station at 1740 UTC. The interference can be heard here.
The late "Havana Moon" reported in his own publication "The Numbers Factsheet" in October 1990 that "one particularly dangerous station has been interfering with air to ground traffic on 6577 kHz, a frequency allocated to international aeronautical communications in the busy Caribbean
sector". "On at least one monitored transmission, the air traffic controller at ARINC moved the pilot to an alternate frequency as the numbers transmission was totally blocking the frequency from effective use".
A station operated by the West German BND agency
whose callsign was "Hotel Kilo" used to transmit on 9450 kHz, interfering with Radio Moscow (now The Voice of Russia
) which used the same frequency. A tape recording of the interference was submitted to Radio Moscow which prompted this response.
SW Radio Africa transmits from Meyerton, South Africa, on 4880 kHz and is the "Independent Voice of Zimbabwe". A video of the Mossad E10 station "Uniform Lima X-Ray" interfering with the African station.
The religious station WYFR
transmits from Okeechobee, Florida
, USA, on 6855 kHz. It is regularly affected by a Cuban Spanish number station using V2. [NOTE: V2, E7, and other such identifiers used here are part of the "Enigma" taxonomy, which can be found at http://www.spynumbers.com/profiles/enigma.html, identifying the types of numbers stations]. A video shows the V2 interfering with the American station.
A BBC
frequency, 7325 kHz, has also been used. This prompted a letter to the BBC from a listener in Andorra
. She wrote to the World Service
"Waveguide" programme complaining that her listening had been spoiled by a female voice reading out numbers in English and she asked the announcer what this interference was. The BBC presenter laughed at the suggestion of spy activity. He had consulted the experts at Bush House (BBC World Service headquarters) who declared that the voice was reading out nothing more sinister than snowfall figures for the ski-slopes near the listener's home. With more research into this case, short wave enthusiasts are fairly sure that this was a numbers station being broadcast on a random frequency. The likelihood of the broadcast being snow readings is in doubt because it would have been illegal to broadcast on an already used frequency.
Radio Ukraine International uses 9950 kHz in the 31 metre band. At 1610 UTC on Thursday 22 November 2007, the powerful S06 Russian number station transmitted a call up of "425".
Radio Mediterranee Int. (Medi 1) transmits on 9575 kHz from Nador, Morocco. On 11 September 2008, the English language number station E11a sent a message on 9576 kHz, which was hidden in the upper sideband of the Moroccan station.
" in place; i.e. "We won't jam yours if you don't jam ours". In addition, the haphazard nature of some stations, e.g. not having a fixed schedule or frequency, also makes jamming more difficult because the broadcast may go undetected.
Historical examples of jamming:
For example, the well known, defunct Lincolnshire Poacher
station has the designation E3 (or E03), the Cuban "Atención" station has designation V2 (or V02). The most recent station to be given a designation is the Vietnamese Language
station V30.
Some stations have also been stripped of their designation if they are discovered not to be a numbers station. This was the case for E22 which was discovered in 2005 to be test transmissions for All India Radio
.
Shortwave
Shortwave radio refers to the upper MF and all of the HF portion of the radio spectrum, between 1,800–30,000 kHz. Shortwave radio received its name because the wavelengths in this band are shorter than 200 m which marked the original upper limit of the medium frequency band first used...
radio station of uncertain origin. In the 1950s, Time magazine reported that the numbers stations first appeared shortly after World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
and were using a format that had been used to send weather data during that war.
Numbers stations generally broadcast artificially generated voices
Speech synthesis
Speech synthesis is the artificial production of human speech. A computer system used for this purpose is called a speech synthesizer, and can be implemented in software or hardware...
reading streams of numbers, words, letters (sometimes using a spelling alphabet
Spelling alphabet
A spelling alphabet, radio alphabet, or telephone alphabet is a set of words which are used to stand for the letters of an alphabet. Each word in the spelling alphabet typically replaces the name of the letter with which it starts...
), tunes or Morse code
Morse code
Morse code is a method of transmitting textual information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment...
. They are in a wide variety of languages and the voices are usually female, although sometimes men's or children's voices are used.
Evidence supports popular assumptions that the broadcasts are used to send messages to spies
Espionage
Espionage or spying involves an individual obtaining information that is considered secret or confidential without the permission of the holder of the information. Espionage is inherently clandestine, lest the legitimate holder of the information change plans or take other countermeasures once it...
. This usage has not been publicly acknowledged by any government that may operate a numbers station, although two QSL
QSL
QSL is one of the Q codes used in radiocommunication and radio broadcasting. A Q code message can stand for a statement or a question . In this case, QSL? means "do you confirm receipt of my transmission?" while QSL means "I confirm receipt of your transmission". Some also take it to mean "Query...
s have been received from numbers stations by shortwave listeners
Shortwave listening
Shortwave listening is the hobby of listening to shortwave radio broadcasts located on frequencies between 1700 kHz and 30 MHz. Listeners range from casual users seeking international news and entertainment programming to hobbyists immersed in the technical aspects of radio reception and DXing...
who sent reception reports to said stations, which is the expected behaviour of a non-clandestine station.
In 2001, the United States tried the Cuban Five on the charge of spying for Cuba. That group had received and decoded messages that had been broadcast from a Cuban numbers station. Also in 2001, Ana Belen Montes, a senior US Defense Intelligence Agency
Defense Intelligence Agency
The Defense Intelligence Agency is a member of the Intelligence Community of the United States, and is the central producer and manager of military intelligence for the United States Department of Defense, employing over 16,500 U.S. military and civilian employees worldwide...
analyst, was arrested and charged with espionage. The federal prosecutors stated: "Montes communicated with the Cuban Intelligence Service through encrypted messages and received her instructions through encrypted shortwave transmissions from Cuba." In 2006, Carlos Alvarez
Carlos Alvarez (professor)
Carlos M. Alvarez is an associate professor of educational leadership and policy studies at Florida International University who, along with his second wife Elsa, was charged in January 2006 with speaking with Cuba on things that were happening in the United States.Alvarez was born in Cárdenas,...
and his wife, Elsa
Elsa Alvarez
Elsa Alvarez , along with her husband Carlos Alvarez, is accused of spying on Cuban exile groups in the United States on behalf of the Cuban government....
, were arrested and charged with espionage. The U. S. District Court
Florida stated: "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 Service to further that conspiracy.
It has been reported that the United States uses numbers stations to communicate encoded information to persons in other countries. The State Department operated several stations, such as KKN50, that broadcast similar "numbers" messages.
Suspected origins and use
According to the notes of The Conet ProjectThe Conet Project
The Conet Project: Recordings of Shortwave Numbers Stations is a four-CD set of recordings of numbers stations, mysterious shortwave radio stations of uncertain origin believed to be operated by government agencies to communicate with spies "in the field"...
, which has compiled recordings of these transmissions, numbers stations have been reported since World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
. If accurate, this would make numbers stations among the earliest radio broadcasts.
It has long been speculated, and was argued in court in one case, that these stations operate as a simple and foolproof method for government agencies to communicate with spies
SPY
SPY is a three-letter acronym that may refer to:* SPY , ticker symbol for Standard & Poor's Depositary Receipts* SPY , a satirical monthly, trademarked all-caps* SPY , airport code for San Pédro, Côte d'Ivoire...
working undercover. According to this theory, the messages are encrypted with a one-time pad
One-time pad
In cryptography, the one-time pad is a type of encryption, which has been proven to be impossible to crack if used correctly. Each bit or character from the plaintext is encrypted by a modular addition with a bit or character from a secret random key of the same length as the plaintext, resulting...
, to avoid any risk of decryption by the enemy. As evidence, numbers stations have changed details of their broadcasts or produced special, nonscheduled broadcasts coincident with extraordinary political events, such as the August Coup
Soviet coup attempt of 1991
The 1991 Soviet coup d'état attempt , also known as the August Putsch or August Coup , was an attempt by a group of members of the Soviet Union's government to take control of the country from Soviet president Mikhail Gorbachev...
of 1991 in the Soviet Union.
Number Stations are also acknowledged for espionage purposes in Robert Wallace and H. Keith Melton's Spycraft (p. 438):
Others speculate that some of these stations may be related to illegal drug smuggling
Smuggling
Smuggling is the clandestine transportation of goods or persons, such as out of a building, into a prison, or across an international border, in violation of applicable laws or other regulations.There are various motivations to smuggle...
operations. Unlike government stations, smugglers' stations would need to be lower powered and irregularly operated, to avoid location by triangulated direction finding
Direction finding
Direction finding refers to the establishment of the direction from which a received signal was transmitted. This can refer to radio or other forms of wireless communication...
, followed by government raids. However, numbers stations have transmitted with impunity for decades, so they are generally presumed to be operated or sponsored only by governments. Also, numbers station transmissions in the international shortwave bands typically transmit high power levels that might be unavailable to ranches, farms, or plantations in isolated drug-growing regions. However, if the intended recipient has the space for an outdoor long wire antenna, and can afford to wait to the correct time of day for propagation to 'open' then the transmitter power requirement would be modest, a few tens of watts .
High frequency
High frequency
High frequency radio frequencies are between 3 and 30 MHz. Also known as the decameter band or decameter wave as the wavelengths range from one to ten decameters . Frequencies immediately below HF are denoted Medium-frequency , and the next higher frequencies are known as Very high frequency...
radio signals transmitted at relatively low power can travel around the world under ideal propagation
Radio propagation
Radio propagation is the behavior of radio waves when they are transmitted, or propagated from one point on the Earth to another, or into various parts of the atmosphere...
conditions, which are affected by local RF noise
Electromagnetic interference
Electromagnetic interference is disturbance that affects an electrical circuit due to either electromagnetic induction or electromagnetic radiation emitted from an external source. The disturbance may interrupt, obstruct, or otherwise degrade or limit the effective performance of the circuit...
levels, weather, season, and sunspots, and can then be received with a properly tuned antenna of adequate size, and a good receiver. However, spies often have to work only with available hand held receivers, sometimes under difficult local conditions, and in all seasons and sunspot cycles. Only very large transmitters, perhaps up to 500,000 watts, are guaranteed to get through to nearly any basement-dwelling spy, nearly any place on earth, nearly all of the time. Some governments may not need a numbers station with global coverage if they only send spies to nearby countries.
Although no broadcaster or government has acknowledged transmitting the numbers, a 1998 article in The Daily Telegraph quoted a spokesperson for the Department of Trade and Industry (the government department that, at that time, regulated radio broadcasting in the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
) as saying, "These [numbers stations] are what you suppose they are. People shouldn't be mystified by them. They are not for, shall we say, public consumption."
On some stations, tones can be heard in the background. It has been suggested that in such cases the voice may be an aid to tuning to the correct frequency, with the coded message being sent by modulating
Modulation
In electronics and telecommunications, modulation is the process of varying one or more properties of a high-frequency periodic waveform, called the carrier signal, with a modulating signal which typically contains information to be transmitted...
the tones, perhaps using a technology such as burst transmission
Burst transmission
In telecommunication, the term burst transmission or data burst has the following meanings:# Any relatively high-bandwidth transmission over a short period of time...
.
The use of number stations as a method of espionage is discussed in Spycraft (p. 37):
Identifying and locating
Numbers stations are often given nicknames by enthusiasts, often reflecting some distinctive element of the station such as their interval signalInterval signal
An interval signal, or tuning signal, is a characteristic sound or musical phrase used in international broadcasting and by some domestic broadcasters...
. For example, the "Lincolnshire Poacher
Lincolnshire Poacher (numbers station)
"The Lincolnshire Poacher" was the nickname of a mysterious, powerful shortwave numbers station that used two bars from the English folk song "The Lincolnshire Poacher" as an interval signal. The radio station was believed to be operated by the British Secret Intelligence Service and emanated from...
", formerly one of the best known numbers stations (generally thought to be run by SIS
Secret Intelligence Service
The Secret Intelligence Service is responsible for supplying the British Government with foreign intelligence. Alongside the internal Security Service , the Government Communications Headquarters and the Defence Intelligence , it operates under the formal direction of the Joint Intelligence...
, as its transmissions have been traced to RAF Akrotiri
RAF Akrotiri
Royal Air Force Station Akrotiri, more commonly known as RAF Akrotiri , is a large Royal Air Force station, on the Mediterranean island of Cyprus. It is located in the Western Sovereign Base Area, one of two areas which comprise Akrotiri and Dhekelia, a British Overseas Territory, administered as a...
in Cyprus
Cyprus
Cyprus , officially the Republic of Cyprus , is a Eurasian island country, member of the European Union, in the Eastern Mediterranean, east of Greece, south of Turkey, west of Syria and north of Egypt. It is the third largest island in the Mediterranean Sea.The earliest known human activity on the...
), played the first two bars of the folk song "The Lincolnshire Poacher
The Lincolnshire Poacher
"The Lincolnshire Poacher" is a traditional English folk song.The Lincolnshire Poacher can also refer to:*Lincolnshire Poacher , a numbers station*Lincolnshire Poacher , a type of cheese...
" before each string of numbers. "Magnetic Fields" plays music from French electronic music
Electronic music
Electronic music is music that employs electronic musical instruments and electronic music technology in its production. In general a distinction can be made between sound produced using electromechanical means and that produced using electronic technology. Examples of electromechanical sound...
ian Jean Michel Jarre
Jean Michel Jarre
Jean Michel André Jarre is a French composer, performer and music producer. He is a pioneer in the electronic, ambient and New Age genres, and known as an organiser of outdoor spectacles of his music featuring lights, laser displays, and fireworks.Jarre was raised in Lyon by his mother and...
before and after each set of numbers. The "Atención" station begins its transmission with the Spanish
Spanish language
Spanish , also known as Castilian , is a Romance language in the Ibero-Romance group that evolved from several languages and dialects in central-northern Iberia around the 9th century and gradually spread with the expansion of the Kingdom of Castile into central and southern Iberia during the...
word "¡Atención!"
Although it is time-consuming and may require costly global travel to pinpoint the source of a radio transmission in the shortwave band, errors at the transmission site, radio direction-finding, and a knowledge of shortwave radio propagation have provided armchair detective
Armchair detective
Armchair detective is a term used for a fictional investigator who does not personally visit a crime scene or interview witnesses; instead, he or she either reads the story of the crime in a newspaper, or has it recounted to him by another person. As the armchair detective never sees any of the...
s clues to some number station locations.
For example, the "Atención" station was thought to be from Cuba
Cuba
The Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...
, as a supposed error allowed Radio Habana Cuba to be carried on the frequency. Whether the frequency of Radio Habana Cuba and the frequency of the "Atención" station merely interfered with each other or whether the operator of the station was listening to the radio and it accidentally ended up on the air is unclear.
Also, several articles in the radio magazine Popular Communications
Popular Communications
Popular Communications is a magazine with content relating to the radio hobby, including scanners, shortwave radio, CB, amateur radio, AM and FM broadcast band listening, radio history, and vintage radio restoration...
published in the 1980s and early 1990s described hobbyists using portable radio direction-finding equipment to locate numbers stations in Florida and in the Warrenton
Warrenton, Virginia
Warrenton is a town in Fauquier County, Virginia, United States. The population was 6,670 at the 2000 census, and 14,634 at the 2010 estimate. It is the county seat of Fauquier County. Public schools in the town include Fauquier High School, Warrenton Middle School, Taylor Middle School and two...
, Virginia
Virginia
The Commonwealth of Virginia , is a U.S. state on the Atlantic Coast of the Southern United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there...
, areas of the United States. From the outside, they spotted the station's antenna inside a military facility. The station hunter speculated that the antenna's transmitter at the facility was connected by a telephone wire pair to a source of spoken numbers in the Washington, D.C.
Washington, D.C.
Washington, D.C., formally the District of Columbia and commonly referred to as Washington, "the District", or simply D.C., is the capital of the United States. On July 16, 1790, the United States Congress approved the creation of a permanent national capital as permitted by the U.S. Constitution....
, area. The author said the Federal Communications Commission
Federal Communications Commission
The Federal Communications Commission is an independent agency of the United States government, created, Congressional statute , and with the majority of its commissioners appointed by the current President. The FCC works towards six goals in the areas of broadband, competition, the spectrum, the...
would not comment on public inquiries about American territory numbers stations.
The Atención spy case evidence
Atención 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.United States government evidence included the following three examples of decoded Atención messages. (Not reported whether the original clear texts were in Spanish, although the phrasing of "Day of the Woman" would indicate so.):
- "prioritize and continue to strengthen friendship with Joe and Dennis" [68 characters]
- "Under no circumstances should [agents] German nor Castor fly with BTTR or another organization on days 24, 25, 26, and 27." [112 characters] (BTTR is the anti-Castro airborne group Brothers to the RescueBrothers to the RescueBrothers to the Rescue is a Miami-based activist organization headed by José Basulto. Formed by Cuban exiles, the group is widely known for its opposition to the Cuban government and, then President, Fidel Castro...
) - "Congratulate all the female comrades for International Day of the Woman." [71 characters] (Probably a simple greeting for March 8, International Women's DayInternational Women's DayInternational Women's Day , originally called International Working Women’s Day, is marked on March 8 every year. In different regions the focus of the celebrations ranges from general celebration of respect, appreciation and love towards women to a celebration for women's economic, political and...
)
At the rate of one spoken number per character per second, each of these sentences takes a minute or more to transmit.
The moderator of an e-mail list for global numbers station hobbyists claimed "Someone on the Spooks list had already cracked the code for a repeated transmission [from Havana to Miami] if it was received garbled." Such code-breaking is possible if a one-time pad
One-time pad
In cryptography, the one-time pad is a type of encryption, which has been proven to be impossible to crack if used correctly. Each bit or character from the plaintext is encrypted by a modular addition with a bit or character from a secret random key of the same length as the plaintext, resulting...
decoding key is used more than once.
Formats
Generally, numbers stations follow a basic format, although there are many differences in details between stations. Transmissions usually begin on the hour or half-hour.The prelude or introduction of a transmission (from which stations' informal nicknames are often derived) includes some kind of identifier, either for the station itself and/or for the intended recipient. This can take the form of numeric or radio-alphabet "code names" (e.g. "Charlie India Oscar", "250 250 250"), characteristic phrases (e.g. "¡Atención!", "1234567890"), and sometimes musical or electronic sounds (e.g. "The Lincolnshire Poacher", "Magnetic Fields"). Sometimes, as in the case of the Israel
Israel
The State of Israel is a parliamentary republic located in the Middle East, along the eastern shore of the Mediterranean Sea...
i radio-alphabet stations, the prelude can also signify the nature or priority of the message to follow (e.g.(hypothetically) "Charlie India Oscar-2", indicating that no message follows). Often the prelude repeats for a period before the body of the message begins.
There is usually an announcement of the number of number-groups in the message, then the groups are recited. Groups are usually either four or five digits or radio-alphabet letters. The groups are typically repeated, either by reading each group twice, or by repeating the entire message as a whole.
Some stations send more than one message during a transmission. In this case, some or all of the above process is repeated, with different contents.
Finally, after all the messages have been sent, the station will sign off in some characteristic fashion. Usually it will simply be some form of the word "end" in whatever language the station uses (e.g. "end of message, end of transmission"; "Ende"; "fini"; "final"; "конец"). Some stations, especially those thought to originate from the former Soviet Union
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
, end with a series of zeros, e.g. "000 000"; others end with music or other sundry sounds.
Because of the secretive nature of the messages, the cryptographic function
Cryptography
Cryptography is the practice and study of techniques for secure communication in the presence of third parties...
employed by particular stations is not publicly known, except in one or possibly two cases. It is assumed that most stations use a one-time pad
One-time pad
In cryptography, the one-time pad is a type of encryption, which has been proven to be impossible to crack if used correctly. Each bit or character from the plaintext is encrypted by a modular addition with a bit or character from a secret random key of the same length as the plaintext, resulting...
that would make the contents of these number groups indistinguishable from randomly generated numbers or digits. In one definitely known case, West Germany did use a one-time pad for numbers transmissions.
Transmission technology
Although few numbers stations have been tracked down by location, the technology used to transmit the numbers has historically been clear — stock shortwave transmitterTransmitter
In electronics and telecommunications a transmitter or radio transmitter is an electronic device which, with the aid of an antenna, produces radio waves. The transmitter itself generates a radio frequency alternating current, which is applied to the antenna. When excited by this alternating...
s using powers from 10 kW to 100 kW.
Amplitude modulated
Amplitude modulation
Amplitude modulation is a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. AM works by varying the strength of the transmitted signal in relation to the information being sent...
(AM) transmitters with optionally variable frequency, using class-C power output stages with plate modulation, are the workhorses of international shortwave broadcasting, including numbers stations.
Application of spectrum analysis
Spectrum analyzer
A spectrum analyzer measures the magnitude of an input signal versus frequency within the full frequency range of the instrument. The primary use is to measure the power of the spectrum of known and unknown signals...
to number station signals has revealed the presence of data bursts, RTTY
Radioteletype
Radioteletype is a telecommunications system consisting originally of two or more electromechanical teleprinters in different locations, later superseded by personal computers running software to emulate teleprinters, connected by radio rather than a wired link.The term radioteletype is used to...
-modulated subcarrier
Subcarrier
A subcarrier is a separate analog or digital signal carried on a main radio transmission, which carries extra information such as voice or data. More technically, it is an already-modulated signal, which is then modulated into another signal of higher frequency and bandwidth...
s, phase-shifted carriers
Phase-shift keying
Phase-shift keying is a digital modulation scheme that conveys data by changing, or modulating, the phase of a reference signal ....
, and other unusual transmitter modulations like polytones
Multiple frequency-shift keying
Multiple frequency-shift keying is a variation of frequency-shift keying that uses more than two frequencies. MFSK is a form of M-ary orthogonal modulation, where each symbol consists of one element from an alphabet of orthogonal waveforms...
. (RTTY-modulated subcarriers were also present on some U.S. commercial radio transmissions during the Cold War.)
The frequently reported use of high tech modulations like data bursts
Burst transmission
In telecommunication, the term burst transmission or data burst has the following meanings:# Any relatively high-bandwidth transmission over a short period of time...
, in combination or sequence with spoken numbers, suggest transmissions for differing intelligence operations.
For spies in the field, low tech spoken number transmissions continue to have advantages in the 21st century. High tech data receiving equipment is difficult to obtain, and being caught with more than a civilian shortwave news radio could be construed as evidence of spying. Yet governments' embassies, aircraft, and ships at sea are known to possess complex receiving equipment that could make regular use of encrypted data transmissions from the home country. These probably include charts and photos that require more transmitted data than can be sent efficiently using spoken numbers.
The USSR and superpower number stations
During the Cold WarCold War
The Cold War was the continuing state from roughly 1946 to 1991 of political conflict, military tension, proxy wars, and economic competition between the Communist World—primarily the Soviet Union and its satellite states and allies—and the powers of the Western world, primarily the United States...
there was substantial evidence from the amateur radio community that the USSR may have been using transmitters to reach agents in Western Europe, North Africa, and possibly North America with output power ranging up to 500 kW. HF
High frequency
High frequency radio frequencies are between 3 and 30 MHz. Also known as the decameter band or decameter wave as the wavelengths range from one to ten decameters . Frequencies immediately below HF are denoted Medium-frequency , and the next higher frequencies are known as Very high frequency...
direction finding evidence that was collected by many different sets of amateurs in Europe, Africa, and the Americas during the Cold War substantiates number stations broadcasting from the East of the Urals
Ural Mountains
The Ural Mountains , or simply the Urals, are a mountain range that runs approximately from north to south through western Russia, from the coast of the Arctic Ocean to the Ural River and northwestern Kazakhstan. Their eastern side is usually considered the natural boundary between Europe and Asia...
.
USSR technical literature shows that the USSR pioneered HRS 8/8/1 directional HF antennas for shortwave news and information broadcasting in the late 1960s–mid 1970s. Thus it is possible that lower transmitter powers (like 100 kW) were used in the 1980s (late Cold War) for numbers station use.
Documented instances of interference to broadcasts
The North KoreaNorth Korea
The Democratic People’s Republic of Korea , , is a country in East Asia, occupying the northern half of the Korean Peninsula. Its capital and largest city is Pyongyang. The Korean Demilitarized Zone serves as the buffer zone between North Korea and South Korea...
n foreign language service Voice of Korea
Voice of Korea
Voice of Korea is the international broadcasting service of the Democratic People's Republic of Korea. It broadcasts primarily information in Korean, Chinese, Spanish, German, English, French, Russian, Japanese, and Arabic...
began to broadcast on the Lincolnshire Poacher's
Lincolnshire Poacher (numbers station)
"The Lincolnshire Poacher" was the nickname of a mysterious, powerful shortwave numbers station that used two bars from the English folk song "The Lincolnshire Poacher" as an interval signal. The radio station was believed to be operated by the British Secret Intelligence Service and emanated from...
former frequency, 11545 kHz, in 2006, possibly to deliberately interfere with its propagation. This clash can be viewed in video format. The apparent target zone for the Lincolnshire Poacher signals originating in Cyprus was the Middle East
Middle East
The Middle East is a region that encompasses Western Asia and Northern Africa. It is often used as a synonym for Near East, in opposition to Far East...
, not the Far East
Far East
The Far East is an English term mostly describing East Asia and Southeast Asia, with South Asia sometimes also included for economic and cultural reasons.The term came into use in European geopolitical discourse in the 19th century,...
which is covered by its sister station Cherry Ripe
Cherry Ripe (numbers station)
Cherry Ripe was the nickname of a mysterious, powerful shortwave numbers station that used several bars from the English folk song "Cherry Ripe" as an interval signal. The station was believed to be operated by the British Secret Intelligence Service and to have emanated from Australia. It was...
.
On 27 September 2006, amateur radio transmissions in the 30 m band were affected by an E7 "Russian Man" number station at 1740 UTC. The interference can be heard here.
The late "Havana Moon" reported in his own publication "The Numbers Factsheet" in October 1990 that "one particularly dangerous station has been interfering with air to ground traffic on 6577 kHz, a frequency allocated to international aeronautical communications in the busy Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
sector". "On at least one monitored transmission, the air traffic controller at ARINC moved the pilot to an alternate frequency as the numbers transmission was totally blocking the frequency from effective use".
A station operated by the West German BND agency
Bundesnachrichtendienst
The Bundesnachrichtendienst [ˌbʊndəsˈnaːχʁɪçtnˌdiːnst] is the foreign intelligence agency of Germany, directly subordinated to the Chancellor's Office. Its headquarters are in Pullach near Munich, and Berlin . The BND has 300 locations in Germany and foreign countries...
whose callsign was "Hotel Kilo" used to transmit on 9450 kHz, interfering with Radio Moscow (now The Voice of Russia
Voice of Russia
Voice of Russia is the Russian government's international radio broadcasting service owned by the All-Russia State Television and Radio Company. Its predecessor Radio Moscow was the official international broadcasting station of the Union of Soviet Socialist Republics.-Early years:Radio Moscow...
) which used the same frequency. A tape recording of the interference was submitted to Radio Moscow which prompted this response.
SW Radio Africa transmits from Meyerton, South Africa, on 4880 kHz and is the "Independent Voice of Zimbabwe". A video of the Mossad E10 station "Uniform Lima X-Ray" interfering with the African station.
The religious station WYFR
WYFR
WYFR is a shortwave radio station located in Okeechobee, Florida, United States. The station is owned by Family Stations, Inc., as part of the Family Radio network, and broadcasts traditional Christian radio programming to international audiences....
transmits from Okeechobee, Florida
Okeechobee, Florida
Okeechobee is a city in Okeechobee County, Florida, United States. The population was 5,376 at the 2000 census. As of 2004, the population recorded by the U.S. Census Bureau is 5,784. It is the county seat of Okeechobee County. The Speckled Perch Festival is held annually in honor of the most...
, USA, on 6855 kHz. It is regularly affected by a Cuban Spanish number station using V2. [NOTE: V2, E7, and other such identifiers used here are part of the "Enigma" taxonomy, which can be found at http://www.spynumbers.com/profiles/enigma.html, identifying the types of numbers stations]. A video shows the V2 interfering with the American station.
A BBC
BBC
The British Broadcasting Corporation is a British public service broadcaster. Its headquarters is at Broadcasting House in the City of Westminster, London. It is the largest broadcaster in the world, with about 23,000 staff...
frequency, 7325 kHz, has also been used. This prompted a letter to the BBC from a listener in Andorra
Andorra
Andorra , officially the Principality of Andorra , also called the Principality of the Valleys of Andorra, , is a small landlocked country in southwestern Europe, located in the eastern Pyrenees mountains and bordered by Spain and France. It is the sixth smallest nation in Europe having an area of...
. She wrote to the World Service
BBC World Service
The BBC World Service is the world's largest international broadcaster, broadcasting in 27 languages to many parts of the world via analogue and digital shortwave, internet streaming and podcasting, satellite, FM and MW relays...
"Waveguide" programme complaining that her listening had been spoiled by a female voice reading out numbers in English and she asked the announcer what this interference was. The BBC presenter laughed at the suggestion of spy activity. He had consulted the experts at Bush House (BBC World Service headquarters) who declared that the voice was reading out nothing more sinister than snowfall figures for the ski-slopes near the listener's home. With more research into this case, short wave enthusiasts are fairly sure that this was a numbers station being broadcast on a random frequency. The likelihood of the broadcast being snow readings is in doubt because it would have been illegal to broadcast on an already used frequency.
Radio Ukraine International uses 9950 kHz in the 31 metre band. At 1610 UTC on Thursday 22 November 2007, the powerful S06 Russian number station transmitted a call up of "425".
Radio Mediterranee Int. (Medi 1) transmits on 9575 kHz from Nador, Morocco. On 11 September 2008, the English language number station E11a sent a message on 9576 kHz, which was hidden in the upper sideband of the Moroccan station.
Attempted jamming of number stations
Numbers station transmissions have often been the target of jamming attempts. Despite this targeting, many number stations continue to broadcast unhindered. Several theories exist that aid in explaining the inability to effectively jam the transmissions. With only a finite number of jamming transmitters available at any given time, it may be more efficient to block clandestine stations intended for a large audience rather than a message intended for a single person. Another theory is that there may be a "gentlemen's agreementGentlemen's agreement
A gentlemen's agreement is an informal agreement between two or more parties. It may be written, oral, or simply understood as part of an unspoken agreement by convention or through mutually beneficial etiquette. The essence of a gentlemen's agreement is that it relies upon the honor of the parties...
" in place; i.e. "We won't jam yours if you don't jam ours". In addition, the haphazard nature of some stations, e.g. not having a fixed schedule or frequency, also makes jamming more difficult because the broadcast may go undetected.
Historical examples of jamming:
- The E10 YHF being jammed by the mysterious "Chinese Music Station". This jammer has been dubbed the Chinese Fire Dragon Jammer and purportedly comes from Hainan Island which is located in the Gulf of TonkinGulf of TonkinThe Gulf of Tonkin is an arm of the South China Sea, lying off the coast of northeastern Vietnam.-Etymology:The name Tonkin, written "東京" in Hán tự and Đông Kinh in romanised Vietnamese, means "Eastern Capital", and is the former toponym for Hanoi, the capital of Vietnam...
and is a part of the People's Republic of ChinaPeople's Republic of ChinaChina , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...
. - The E3 Lincolnshire Poacher station was at one time in the early 1990s the target for "bubble" or "warble" jammers. In this example, the jammer appears to be in some difficulty.
- The E5 CIA station dubbed "Cynthia" by number station monitors has also been the target of the same type of jamming as the above example.
- On 2 September 2008 at 1700 UTC on 9130 kHz, the E10 Mossad station EZI 1 was being jammed whereas its parallel frequency of 6840 kHz was in the clear.
Classification
Although most number stations have various nicknames which usually describe some aspect of the station itself, M. Gauffman of the E.N.I.G.M.A. number stations monitoring group originally assigned a code to each known station. This takes the form of a letter followed by a number (or, in the case of some "X" stations, more letters). The letter indicates the language used by the station in question:- E indicates a station broadcasting in EnglishEnglish languageEnglish is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria...
. - G indicates a station broadcasting in GermanGerman languageGerman is a West Germanic language, related to and classified alongside English and Dutch. With an estimated 90 – 98 million native speakers, German is one of the world's major languages and is the most widely-spoken first language in the European Union....
. - S indicates a station broadcasting in a SlavicSlavic languagesThe Slavic languages , a group of closely related languages of the Slavic peoples and a subgroup of Indo-European languages, have speakers in most of Eastern Europe, in much of the Balkans, in parts of Central Europe, and in the northern part of Asia.-Branches:Scholars traditionally divide Slavic...
language. - V indicates all other languages.
- M is a station broadcasting in Morse CodeMorse codeMorse code is a method of transmitting textual information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment...
. - X indicates all other transmissions such as polytones in addition to some unexplained broadcasts which may not actually be numbers stations.
- T indicates a station broadcasting in an unknown language.
For example, the well known, defunct Lincolnshire Poacher
Lincolnshire Poacher (numbers station)
"The Lincolnshire Poacher" was the nickname of a mysterious, powerful shortwave numbers station that used two bars from the English folk song "The Lincolnshire Poacher" as an interval signal. The radio station was believed to be operated by the British Secret Intelligence Service and emanated from...
station has the designation E3 (or E03), the Cuban "Atención" station has designation V2 (or V02). The most recent station to be given a designation is the Vietnamese Language
Vietnamese language
Vietnamese is the national and official language of Vietnam. It is the mother tongue of 86% of Vietnam's population, and of about three million overseas Vietnamese. It is also spoken as a second language by many ethnic minorities of Vietnam...
station V30.
Some stations have also been stripped of their designation if they are discovered not to be a numbers station. This was the case for E22 which was discovered in 2005 to be test transmissions for All India Radio
All India Radio
All India Radio , officially known since 1956 as Akashvani , is the radio broadcaster of India and a division of Prasar Bharati. Established in 1936, it is the sister service of Prasar Bharati's Doordarshan, the national television broadcaster. All India Radio is one of the largest radio networks...
.
Recordings
- The Conet ProjectThe Conet ProjectThe Conet Project: Recordings of Shortwave Numbers Stations is a four-CD set of recordings of numbers stations, mysterious shortwave radio stations of uncertain origin believed to be operated by government agencies to communicate with spies "in the field"...
: Recordings of Shortwave Numbers Stations is a four-CDCompact DiscThe Compact Disc is an optical disc used to store digital data. It was originally developed to store and playback sound recordings exclusively, but later expanded to encompass data storage , write-once audio and data storage , rewritable media , Video Compact Discs , Super Video Compact Discs ,...
set of recordings of numbers stations. It was first released in 1997 by the Irdial-Discs record label.
See also
- ShortwaveShortwaveShortwave radio refers to the upper MF and all of the HF portion of the radio spectrum, between 1,800–30,000 kHz. Shortwave radio received its name because the wavelengths in this band are shorter than 200 m which marked the original upper limit of the medium frequency band first used...
- RadioteletypeRadioteletypeRadioteletype is a telecommunications system consisting originally of two or more electromechanical teleprinters in different locations, later superseded by personal computers running software to emulate teleprinters, connected by radio rather than a wired link.The term radioteletype is used to...
- Secret broadcastSecret broadcastA secret broadcast is, simply put, a broadcast that is not for the consumption of the general public. The invention of the wireless was initially greeted as a boon by armies and navies. Units could now be coordinated by nearly instant communications. It soon became clear that radio was a double...
- Letter beaconLetter beaconLetter beacons are radio transmissions of uncertain origin and unknown purpose, consisting of only a single repeating Morse code letter. They have been classified into a number of groups according to transmission code and frequency, and it is supposed that the source for most of them is Russia.They...
- Lincolnshire Poacher (numbers station)Lincolnshire Poacher (numbers station)"The Lincolnshire Poacher" was the nickname of a mysterious, powerful shortwave numbers station that used two bars from the English folk song "The Lincolnshire Poacher" as an interval signal. The radio station was believed to be operated by the British Secret Intelligence Service and emanated from...
- Cherry Ripe (numbers station)Cherry Ripe (numbers station)Cherry Ripe was the nickname of a mysterious, powerful shortwave numbers station that used several bars from the English folk song "Cherry Ripe" as an interval signal. The station was believed to be operated by the British Secret Intelligence Service and to have emanated from Australia. It was...
- Yosemite Sam (shortwave)Yosemite Sam (shortwave)Yosemite Sam is the nickname given by DXers to a mysterious number station that first surfaced on December 19, 2004. It transmits on several shortwave frequencies in dual side band: 3700 kHz, 4300 kHz, 6500 kHz, and 10500 kHz...
- UVB-76
- One-way voice link
External links
- All about number stations
- Welcome to number stations Overview of number stations with recordings and schedules
- Global Frequency Database Contains several number stations and much more
- Esquire.com's article about number stations
- Counting Spies – Salon.com's Article on Numbers Stations
- Dark Side of the Band – Wired.com's article about Numbers Stations
- Espionage Is in the Air – Miami New Times, 2001-02-08. Backgrounder to trial of Wasp Network of Cuban spies accused of receiving instructions from the ¡Atención! numbers station.
- Priyom.org – Detailed research with large database of number station messages and frequencies.
- ENIGMA 2000 Number Stations Monitoring Group – expert discussion group with documents and newsletters – best available info about a subject with no official existence
- Numbers & Oddities – detailed information, recordings and database
- Shortwave Espionage – a large amount of information, including sound recordings. Read the book "Secret Signals – The Euronumbers Mystery"
- Numbers Stations Detailed information, images and samples of Numbers Stations
- Numbers Relay Page Internet alternative to Numbers Stations
- Theoretical ECM model for Agent -> HQ messaging
- The Conet Project from Irdial, and MP3s of the 4 CD set at hyperreal.org and archive.org
- NPRNPRNPR, formerly National Public Radio, is a privately and publicly funded non-profit membership media organization that serves as a national syndicator to a network of 900 public radio stations in the United States. NPR was created in 1970, following congressional passage of the Public Broadcasting...
's Lost and Found Sound, 26 May 2000: The Shortwave Numbers Mystery - NPRNPRNPR, formerly National Public Radio, is a privately and publicly funded non-profit membership media organization that serves as a national syndicator to a network of 900 public radio stations in the United States. NPR was created in 1970, following congressional passage of the Public Broadcasting...
's All Things ConsideredAll Things ConsideredAll Things Considered is the flagship news program on the American network National Public Radio. It was the first news program on NPR, and is broadcast live worldwide through several outlets...
, 12 November 2004: Music By The 'Number Stations' - Tracking The Lincolnshire Poacher BBC Radio 4 programme on Number Stations – Streaming audio.
- KUTV video about Numbers Stations
- Numbers Monitoring, A website containing .wav recordings of transmissions from Number Stations.
- The Numbers Game, another site offering mp3 recordings including that of voices and songs played.
- The Richard Syrett show on 1010 CFRB Toronto Canada 27 May 2008.
- Fringe: Season 3, Episode 6: '6955 kHz'Fringe (season 3)The third season of the American science fiction television series Fringe premiered on Fox on September 23, 2010, and concluded on May 6, 2011, consisting of 22 episodes. The series is produced by Bad Robot Productions in association with Warner Bros...
. This science-fiction television show speculates that numbers stations emanate from an ancient, pre-human civilization. In the episode, the stations are used to transmit a signal that wipes the memory of certain listeners.