Numbers station

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"Lincolnshire Poacher"
Recording of the E03 "Lincolnshire Poacher" interval signal, followed by a coded transmission of five numbers, 0-2-5-8-8.
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Cuban numbers station HM01
A recording of The Gong numbers station, run by the National People's Army of the German Democratic Republic, from 1988.

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. [1] 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, some appear to have no discernible pattern and broadcast at random times. Stations may have set frequencies in the high-frequency band. [2]

Contents

Numbers stations have been reported since at least the start of World War I and continue in use today. Amongst amateur radio enthusiasts there is an interest in monitoring and classifying numbers stations, with many being given nicknames to represent their quirks or origins.

History

According to the notes of The Conet Project , [3] [4] which has compiled recordings of these transmissions, number stations have been reported since World War I 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. [5]

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. [6]

Many stations from this era continue to broadcast and some long-time stations may have been taken over by different operators. [7] [8] The Czech Ministry of the Interior and the Swedish Security Service have both acknowledged the use of numbers stations by Czechoslovakia for espionage, [9] [10] [11] with declassified documents proving the same. Few QSL responses have been received from numbers stations [12] by shortwave listeners [13] 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. [14] [15]

One well-known numbers station was the E03 "Lincolnshire Poacher", [16] which is thought to have been run by the British Secret Intelligence Service. [17] 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. [18]

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. [19]

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. [19]

The United States government's evidence included the following three examples of decoded Atención messages. [19]

The moderator of an e-mail list for global numbers station hobbyists claimed that "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 may be possible if a one-time pad decoding key is used more than once. [19] If used properly, however, the code cannot be broken.

Recent cases

In 2001, Ana Belén Montes, a senior US Defense Intelligence Agency analyst, was arrested and charged with espionage. The federal prosecutors alleged that Montes was able to communicate with the Cuban Intelligence Directorate through encoded messages, with instructions being received 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 for the Southern District of Florida [20] [ which? ] stated that "defendants would receive assignments via shortwave radio transmissions".[ citation needed ]

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. [21] [22] 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. [18] It has been reported that the United States has used number stations to communicate encoded information to persons in other countries. [19] There are also claims that State Department-operated stations, such as KKN50 and KKN44, used to broadcast similar "numbers" messages or related traffic, although these radio stations have been off the air for many years. [23] [24]

North Korea revived number broadcasts in July 2016 after a hiatus of sixteen years, a move which some analysts speculated was psychological war; [25] sixteen such broadcasts occurred in 2017, including unusually timed transmissions in April. [26]

Suspected use for espionage

It has long been speculated, and was argued in one court case, that these stations operate as a simple and fool-proof method for government agencies to communicate with spies working undercover. [27] According to this hypothesis, the messages must have been encrypted with a one-time pad to avoid any risk of decryption by the enemy. Writing in 2008, Wallace & Melton described how numbers stations could be used in this way for espionage: [28]

The one-way voice link (OWVL) described a covert communications system that transmitted messages to an agent's unmodified shortwave radio using the high-frequency shortwave bands between 3 and 30 MHz at a predetermined time, date, and frequency contained in their communications plan. [28]
The transmissions were contained in a series of repeated random number sequences and could only be deciphered using the agent's one-time pad. If proper tradecraft was practised and instructions were precisely followed, an OWVL transmission was considered unbreakable. As long as the agent's cover could justify possessing a shortwave radio and he was not under technical surveillance, high-frequency OWVL was a secure and preferred system for the CIA during the Cold War. [28]

Evidence to support this theory includes the fact that numbers stations have changed details of their broadcasts or produced special, nonscheduled broadcasts coincident with extraordinary political events, such as the attempted coup of August 1991 in the Soviet Union. [29]

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." [30]

Formats

The "Russian Man" station signing off. The numbers read: 83912 83912 10080 10080 46543 46543 –257 257 143 143 –000 00

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.[ citation needed ]

The prelude, introduction, or call-up of a transmission (from which stations' informal nicknames are often derived) includes some kind of identifier, [31] for the station itself, the intended recipient, or both. This can take the form of numeric or radio-alphabet "code names" (e.g. "Charlie India Oscar", "250 250 250", "Six-Niner-Zero-Oblique-Five-Four"), characteristic phrases (e.g. "¡Atención!", "Achtung!", "Ready? Ready?", "1234567890"), and sometimes musical or electronic sounds (e.g. "The Lincolnshire Poacher", "Magnetic Fields"). Sometimes, as in the case of radio-alphabet stations, the prelude can also signify the nature or priority of the message to follow (e.g., it may indicate that no message follows). Often the prelude repeats for a period before the body of the message begins.[ citation needed ]

After the prelude, there is usually an announcement of the number of number-groups in the message, [31] the page to be used from the one-time pad, or other pertinent information. The groups are then 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.[ citation needed ]

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.[ citation needed ]

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., "00000" "000 000"; others end with music or other sounds. [31]

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 [32] ) 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 confirmed case, West Germany did use a one-time pad for numbers transmissions. [33]

Transmission technology

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 best received with a properly tuned antenna (of adequate, possibly conspicuous size) and a good receiver. [19]

Although few numbers stations have been tracked down by location, the technology used to transmit the numbers has historically been clear—stock shortwave transmitters using powers from 10 kW to 100 kW.[ citation needed ]

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.[ citation needed ]

Application of spectrum analysis to numbers station signals has revealed the presence of data bursts, radioteletype-modulated subcarriers, phase-shifted carriers, and other unusual transmitter modulations like polytones. [34] (RTTY-modulated subcarriers were also present on some U.S. commercial radio transmissions during the Cold War. [35] )

The frequently reported use of high-tech modulations like data bursts, in combination or in sequence with spoken numbers, suggests varying transmissions for differing intelligence operations. [36]

The Speech/Morse generator (pictured here) is a machine that has been used for many well-known numbers stations Sprach-Morse-Generator.jpg
The Speech/Morse generator (pictured here) is a machine that has been used for many well-known numbers stations

Those receiving the signals often have to work only with available hand-held receivers, sometimes under difficult local conditions, and in all reception conditions (such as sunspot cycles and seasonal static). [19] However, in the field low-tech spoken number transmissions continue to have advantages even in the 21st century. High-tech data-receiving equipment can be difficult to obtain and even a non-standard civilian shortwave radio can be difficult to obtain in a totalitarian state. [37] Being caught with just a shortwave radio has a degree of plausible deniability, for example, that no spying is being conducted.[ citation needed ]

Interference

Interfering with other broadcasts

The North Korean foreign language service Voice of Korea began to broadcast on the E03 Lincolnshire Poacher's former frequency, 11545 kHz, in 2006, possibly to deliberately interfere with its propagation.[ citation needed ] However, Lincolnshire Poacher broadcasts on three different frequencies, and the remaining two have not been interfered with. 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, E03a Cherry Ripe. [38] [39]

On 27 September 2006, amateur radio transmissions in the 30 m band were affected by an S06 "Russian Man" [40] numbers station at 17:40 UTC. [39]

In October 1990, it was reported that a numbers station had been interfering with communications on 6577 kHz, a frequency used by air traffic in the Caribbean. The interference was such that on at least one monitored transmission, it blocked the channel entirely and forced the air traffic controller to switch the pilot to an alternative frequency. [39]

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 in 1983 complaining that her listening had been spoiled by a female voice reading out numbers in English and 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. After more research into this case, shortwave enthusiasts are fairly certain that this was a numbers station being broadcast on a random frequency. [41]

The Cuban numbers station "HM01" has been known to interfere with shortwave broadcaster Voice of Welt on 11530 kHz. [42]

Attempted jamming

Numbers station transmissions have often been the target of intentional jamming attempts. Despite this targeting, many numbers stations continue to broadcast unhindered. Historical examples of jamming include the E10 (a station thought to originate from Israel's Mossad intelligence agency) being jammed by the "Chinese Music Station" (thought to originate from the People's Republic of China and usually used to jam "Sound of Hope" radio broadcasts which are anti-CCP in nature). [43]

Identification and classification

Monitoring and chronicling transmissions from numbers stations has been a hobby for shortwave and ham radio enthusiasts from as early as the 1970s. [44] Numbers stations are often given nicknames by enthusiasts, often reflecting some distinctive element of the station such as the interval signal. For example, the "Lincolnshire Poacher" station played the first two bars of the folk song "The Lincolnshire Poacher" before each string of numbers. [45] Sometimes these traits have helped to uncover the broadcast location of a station. The "Atención" station was thought to be from Cuba, because a supposed error allowed Radio Havana Cuba to be carried on the frequency. [46] [ full citation needed ]

Although many numbers stations have nicknames which usually describe some aspect of the station itself, these nicknames have sometimes led to confusion among listeners, particularly when discussing stations with similar traits. M. Gauffman of the ENIGMA numbers stations monitoring group originally assigned a code to each known station. [47]

Portions of the original ENIGMA group moved on to other interests in 2000 and the classification of numbers stations was continued by the follow-on group ENIGMA 2000. [48] The document containing the description of each station and its code designation was called the "ENIGMA Control List" until 2016, after which it was incorporated into the "ENIGMA 2000 Active Station List"; the latest edition of the list was published in September 2017. [49] This classification scheme takes the form of a letter followed by a number (or, in the case of some "X" stations, more numbers). [50] The letter indicates the language used by the station in question:

There are also a few other stations [31] with a specific classification:

Some stations have also been stripped of their designation when they were 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. [51]

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References

  1. ↑ Olivia Sorrel-Dejerine (16 April 2014). "The spooky world of the 'numbers stations'". BBC News.
  2. ↑ "Number stations". Priyom.
  3. ↑ Segal, David (3 August 2004). "The shortwave and the calling: For Akin Fernandez, cryptic messages became music to his ears". The Washington Post . p. C01.
  4. ↑ Mason 1991 , pp. 5–6
  5. ↑ Schaum, Ryan (30 November 2014). "The First Numbers Stations". NSRIC.
  6. ↑ Bury, Jan (October 2007). "From the archives: The U.S. and West German agent radio ciphers". Cryptologia. 31 (4): 343–357. doi:10.1080/01611190701578104. ISSN   0161-1194. S2CID   205487634.
  7. ↑ "The spooky world of the 'numbers stations'". BBC News. 16 April 2014. Retrieved 12 July 2021.
  8. ↑ "Numbers Stations Research". Numbers Stations Research.
  9. ↑ "Lyssna på ett hemligt telegram" [Listen to a secret telegram] (in Swedish). Säkerhetspolisen. 23 January 2015. Archived from the original on 8 March 2016. Retrieved 12 March 2016.
  10. ↑ "The Swedish Security Service Releases Info on a Numbers Station". NSRIC. 24 July 2015. Retrieved 12 March 2016.
  11. ↑ Catinka Mannerfelt Agneskog. "Säpos hemliga radiotelegram" (in Swedish). SvD Nyheter. Retrieved 23 January 2015.
  12. ↑ stations KKN44, BFBX and OLX Mason, Simon. "Shortwave Espionage". Archived from the original on 3 December 2011. Retrieved 28 October 2011.
  13. ↑ AMARAL, Cristiano Torres (2021). Guia Moderno do Radioescuta. Brasília: Amazon. p. 333. ISBN   978-65-00-20800-9.
  14. ↑ "OLX". 24 January 2015. Archived from the original on 24 January 2015. Retrieved 23 September 2020.
  15. ↑ Helms, Harry L. (1981). "Espionage Radio Activity". How to Tune the Secret Shortwave Spectrum. Blue Ridge Summit, Pennsylvania: TAB Books. p. 52. ISBN   0-8306-1185-1.
  16. ↑ "E03". Priyom.org. Retrieved 17 June 2017.
  17. ↑ "E03 The LincolnShire Poacher" . Retrieved 6 September 2014.
  18. 1 2 Gorvett, Zaria (15 July 2020). "The ghostly radio station that no one claims to run". BBC Future. Retrieved 12 July 2021.
  19. 1 2 3 4 5 6 7 Sokol, Brett (8 February 2001). "Espionage Is in the Air". Miami New Times. Archived from the original on 21 February 2001.
  20. ↑ United States v. Alvarez, 506 F. Supp. 2d 1285 (S.D. Fla. 2007)
  21. ↑ Rijmenants, Dirk (2013). "Cuban Agent Communications" (PDF). Cipher Machines & Cryptology (PDF). Retrieved 30 December 2013.
  22. ↑ "United States v. Walter Kendall Myers, United States District Court, District of Columbia, no. xxx" (PDF). Retrieved 26 August 2010.
  23. ↑ Helms, Harry L. (1981). "Government and Military Communications". How to Tune the Secret Shortwave Spectrum. Blue Ridge Summit, Pennsylvania: TAB Books]. p. 58. ISBN   0-8306-1185-1.
  24. ↑ Schimmel, Donald W. (1994). The Underground Frequency Guide: A Directory of Unusual, Illegal, and Covert Radio Communications (3 ed.). Solana Beach, California: High Text Publications. pp. 88–95. ISBN   1-878707-17-5.
  25. ↑ Choe, Sang-Hun (21 July 2016). "North Korea revives coded spy broadcasts after 16 year silence". The New York Times . Retrieved 30 July 2016.
  26. ↑ Osbourne, Simon (12 May 2017). "North Korea sends chilling coded radio messages to South Korea amid fears of WW3". Daily Express .
  27. ↑ Wagner, Thomas (2004). "Chapter 6 – So here she was, with a pillow over her head and over the radio ...". If it had Not Been for Fifteen Minutes: A true account of espionage and hair-raising adventure. Retrieved 30 October 2013.
  28. 1 2 3 Wallace & Melton 2008 , p. 438
  29. ↑ Irdial-Discs, included booklet (PDF). hyperreal.org (Report). The Conet Project. p. 59.
  30. ↑ Pescovitz, David (16 September 1999). "Counting spies". Salon. Archived from the original on 19 January 2000. Retrieved 12 March 2016.
  31. 1 2 3 4 "Intro to Numbers Stations". NSRIC. 8 February 2016. Retrieved 12 March 2016.
  32. ↑ In the possible case, the underlying type of encryption might have been stated in the court record of the Atención case when the secretly copied decryption software was introduced into evidence.
  33. ↑ Wagner, Thomas (8 December 2012). "If it had not been for 15 Minutes, Chapter 7". Radio Weblogs. Archived from the original on 2 November 2013. Retrieved 18 March 2022.
  34. ↑ Schimmel, Donald W. (1994). The Underground Frequency Guide: A Directory of Unusual, Illegal, and Covert Radio Communications (3 ed.). Solana Beach, California: High Text Publications, Inc. pp. 27–28. ISBN   1-878707-17-5.
  35. ↑ Collins, Barry W. (July 1997). "The day the U.S. Army invaded W4TLV". QST. 81: 48–49. ISSN   0033-4812.
  36. ↑ "NSNL 15: Voice stations". Cvni.net. 3 July 1999. Archived from the original on 26 January 2021. Retrieved 26 August 2010.
  37. ↑ Wagner, Thomas (24 April 2002). "If it had not been for 15 Minutes, Chapter 6". Radio Weblogs. Archived from the original on 1 November 2014. Retrieved 18 March 2022.
  38. ↑ "E03a". Priyom.org. Retrieved 17 June 2017.
  39. 1 2 3 "Secret Signals". Simonmason.karoo.net. Retrieved 7 November 2015.
  40. ↑ "S06". Priyom.org. Retrieved 17 June 2017.
  41. ↑ "Secret Signals". Simonmason.karoo.net. Archived from the original on 20 February 2007. Retrieved 26 August 2010.
  42. ↑ Anthony Spinelli (18 October 2018), HM01 and Voice of Welt 11530 AM 10 18 2018 1743z, archived from the original on 11 December 2021, retrieved 26 November 2018
  43. ↑ "Chinese Music Station". Archived from the original (Windows Media Audio) on 8 March 2012. Retrieved 16 July 2012.
  44. ↑ Māris Goldmanis, Before enigma; the early numbers stations, monitors NSRIC; retrieved 13 December 2019
  45. ↑ Mason 1991 , pp. 20–21
  46. ↑ Poundstone, William. Big Secrets. p. 197.
  47. ↑ "ENIGMA: The European Numbers Information Gathering and Monitoring Association". NSRIC. Retrieved 24 February 2015.
  48. ↑ "ENIGMA 2000" . Retrieved 1 March 2015.
  49. ↑ "ENIGMA 2000 Active Station List" (PDF). signalshed.com (Booklet). 1.3. ENIGMA 2000. September 2017. Retrieved 25 August 2020.
  50. ↑ Friesen, Christopher (2014). "Spy 'Numbers Stations' still enthrall". Radio World . 38 (2): 14. ISSN   0274-8541.
  51. ↑ "E2K 32 – E22 is not what it seems". www.cvni.net. Archived from the original on 17 November 2007. Retrieved 5 April 2016.
  52. ↑ Dowd, A. A. (25 April 2013). "Movie Review: The Numbers Station". The A.V. Club. Chicago. Archived from the original on 12 March 2016.
  53. ↑ Harvey, Dennis (8 January 2014). "Film Review: 'Banshee Chapter'". Variety . Retrieved 28 December 2023.
  54. ↑ Murray, Noel (12 November 2010). "Fringe: '6995 kHz'". The A.V. Club. Retrieved 1 October 2012.
  55. ↑ "Quartet". Endeavour. Series 5. Episode 5. At 1:09:00. PBS.
  56. ↑ "The truth is way, way out there: how Cold War radio signals inspired new series Truth Seekers". The Guardian . 29 October 2020. Archived from the original on 25 October 2022. Retrieved 1 November 2020.
  57. ↑ Forbes, Malcolm (27 August 2015). "Book review: Mai Jia's In the Dark shines a light on China's secret world". The National . Archived from the original on 3 March 2016. Retrieved 12 March 2016.
  58. ↑ Shachtman, Noah (23 June 2004). "Wilco Pays Up for Spycasts". Wired. Archived from the original on 21 April 2008. Retrieved 12 March 2016.
  59. ↑ "Neil Cicierega – Transmission Lyrics". Genius . Retrieved 30 November 2017.
  60. ↑ Robertson, Derek. "Jóhann Jóhannsson's Track By Track Guide to Orphée". Drowned in Sound . Archived from the original on 15 February 2018. Retrieved 28 December 2023.
  61. ↑ Zorgdrager, Bradley (7 September 2016). "Norma Jean: Polar Similar". Exclaim! . Retrieved 1 November 2020.
  62. ↑ "Fugue State". BBC Radio 4. Retrieved 26 February 2016.
  63. ↑ "The Whisperer in Darkness". BBC Radio 4 Podcasts. Retrieved 5 December 2019.
  64. ↑ "Dead Hand". BBC Radio 4 Limelight. Retrieved 1 April 2022.
  65. ↑ "Welcome to Night Vale Recap: Numbers". The Mary Sue . 4 December 2015. Retrieved 20 November 2020.
  66. ↑ "Magnus 144: Decrypted". Acast. Retrieved 1 July 2021.
  67. ↑ "Skeptoid: Spy Radio: Numbers Stations". Skeptoid. Retrieved 12 February 2022.
  68. ↑ "Signalis Review: Numbers Stations and Numbing Dread". Fanbyte. Retrieved 17 April 2023.
  69. ↑ Milzarski, Eric (27 June 2018). "How numbers stations like the ones in 'Black Ops' worked". We Are The Mighty. Retrieved 20 February 2024.

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