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Sprach-Morse-Generator

A speech/Morse generator.

Overview[]

A numbers station is a category of shortwave radio station characterized by broadcasts of formatted numbers, addressed to intelligence officers operating in foreign countries. Most identified stations use speech synthesis to vocalize numbers, although digital modes, such as Phase-shift keying and Frequency-shift keying as well as Morse code transmissions are not uncommon. Most stations have set time schedules, or schedule patterns, however other stations appear to be broadcast at random times. Stations may or may not have set frequencies in the HF band. 

The first known use of numbers stations was during World War I, and the first possible listener was Archduke Anton of Austria. The numbers were transmitted in Morse code. The Czech Ministry of Interior and the Swedish Security Service have both acknowledged the use of numbers stations by Czechoslovakia for espionage, with declassified documents proving the same. With a few exceptions, no QSL responses have been received from numbers stations by shortwave listeners who sent reception reports to said stations, which is the expected behavior of a non-clandestine station. 

The best known of the numbers stations was the "Lincolnshire Poacher", which is thought to have been run by the British Secret Intelligence Service.

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 Cuban numbers stations. Also in 2001, Ana Belen 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 Florida 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. 

It has been reported that the United States used numbers stations to communicate encoded information to persons in other countries. There are also claims that State Department operated stations, such as KKN50 and KKN44, used to broadcast similar "numbers" messages or related traffic. 

Overview[]

A numbers station is a category of shortwave radio station characterized by broadcasts of formatted numbers, addressed to intelligence officers operating in foreign countries. Most identified stations use speech synthesis to vocalize numbers, although digital modes, such as Phase-shift keying and Frequency-shift keying as well as Morse code transmissions are not uncommon. Most stations have set time schedules, or schedule patterns, however other stations appear to be broadcast at random times. Stations may or may not have set frequencies in the HF band. 

The first known use of numbers stations was during World War I, and the first possible listener was Archduke Anton of Austria.[3] The numbers were transmitted in Morse code. The Czech Ministry of Interior and the Swedish Security Service have both acknowledged the use of numbers stations by Czechoslovakia for espionage, with declassified documents proving the same. With a few exceptions, no QSL responses have been received from numbers stations by shortwave listeners who sent reception reports to said stations, which is the expected behavior of a non-clandestine station. 

The best known of the numbers stations was the "Lincolnshire Poacher", which is thought to have been run by the British Secret Intelligence Service. 

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 Cuban numbers stations. Also in 2001, Ana Belen 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 Florida 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. 

It has been reported that the United States used numbers stations to communicate encoded information to persons in other countries. There are also claims that State Department operated stations, such as KKN50 and KKN44, used to broadcast similar "numbers" messages or related traffic. 

Suspected origins and use[]

According to the notes of The Conet Project, which has compiled recordings of these transmissions, numbers stations have been reported since World War I. If accurate, this would count 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.

Numbers stations are also acknowledged for espionage purposes in Robert Wallace and H. Keith Melton's Spycraft:

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. 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 practiced 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.

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. However, numbers stations have transmitted with impunity for decades, so they are generally presumed to be operated or sponsored by governments. Additionally, numbers station transmissions in the international shortwave bands typically transmit at high power levels that might be unavailable to ranches, farms, or plantations in isolated drug-growing regions. 

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. 

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  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. In such cases, the voice may simply be an aid to tuning to the correct frequency, with the actual coded message being sent by modulating the tones, using a technology such as burst transmission

The use of numbers stations as a method of espionage is discussed in Spycraft: 

  • "The only item Penkovsky used that could properly be called advanced tradecraft was his 'agent-receive' communications through a one-way voice-link. These encoded messages, known as OWVL, were broadcast over shortwave frequencies at predetermined times from a CIA-operated transmitter in Western Europe. Penkovsky listened to these messages on a Panasonic radio—strings of numbers read in a dispassionate voice—and then decoded them using a one-time pad."

Identifying and locating[]

Numbers stations are often given nicknames by enthusiasts, often reflecting some distinctive element of the station such as their interval signal. 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. 

The "Atención" station was thought to be from Cuba, as a supposed error allowed Radio Havana Cuba to be carried on the frequency. 

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 observed the station's antenna inside a military facility, the Warrenton Training Center. 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.

According to an internal Cold War era report of the Polish Ministry of Interior, numbers stations DCF37 (3370 kHz) and DFD21 (4010 kHz) transmitted from West Germany since the early 1950s. 

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. 

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 Rescue) "Congratulate all the female comrades for International Day of the Woman." [71 characters] (Probably a simple greeting for International Women's Day on 8 March) At the rate of one spoken number per character per second, each of these sentences takes more than a minute 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. If used properly, however, the code cannot be broken. 

Formats[]

The prelude, introduction, or call-up 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", "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 the Israeli 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/

After the prelude, there is usually an announcement of the number of number-groups in the message,[26] 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. 

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., "00000" "000 000"; others end with music or other 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 confirmed case, West Germany did use a one-time pad for numbers transmissions. 

Transmission technology[]

General[]

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. 

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, RTTY-modulated subcarriers, phase-shifted carriers, and other unusual transmitter modulations like polytones.[29] (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 in sequence with spoken numbers, suggests varying transmissions for differing intelligence operations. 

Speech and Morse code generators[]

Sprach-Morse-Generator

A speech/Morse generator.

Choir_of_East-German_"speech_morse_generators"

Choir of East-German "speech morse generators"

I had a rare opportunity to make this video with 9 "speech/morse generators" all playing in morse and in speech simultaneously, like in a choir.

A translator can translate to and from Morse code and typed text or speech.

In the field[]

For active 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 just a shortwave radio has a degree of plausible deniability on the grounds that that no spying is being conducted whereas possessing restricted equipment more advanced than a civilian shortwave civil radio would raise more eyebrows and would more quickly be construed as evidence of spying, rather than something as harmlessly commonplace as an AM radio.[citation needed]

Interference with numbers stations[]

Numbers stations interfering with other broadcasts[]

The North Korean 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. However, Lincolnshire Poacher broadcasts on not one, but three different frequencies, of which 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, Cherry Ripe. 

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

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 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 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 sure that this was a numbers station being broadcast on a random frequency. 

Attempted jamming of numbers stations[]

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 YHF being jammed by the mysterious "Chinese Music Station". 

Classification[]

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. 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. The document containing the description of each station and its code designation is called the "ENIGMA Control List", whose 26th edition was published in February 2016. This classification scheme takes the form of a letter followed by a number (or, in the case of some "X" stations, more numbers). The letter indicates the language used by the station in question:

E indicates a station broadcasting in English. G indicates a station broadcasting in German. S indicates a station broadcasting in a Slavic language. V indicates all other languages. M is a station broadcasting in Morse code. X indicates all other transmissions, such as polytones, in addition to some unexplained broadcasts which may not actually be numbers stations. 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. 

There are also a few other stations  with a specific classification:

SK: Digital Mode HM: Hybrid Mode DP: Digital-Pseudo Polytone 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 

Recordings[]

Well known cases[]

W. Germany Vs. Communist Poland[]

According to an internal Cold War era report of the Polish Ministry of Interior, numbers stations DCF37 (3370 kHz) and DFD21 (4010 kHz) transmitted from West Germany since the early 1950s. 

The Lincolnshire Poacher[]

Overview[]

  • Name = "The Lincolnshire Poacher".
  • Area of origin = RAF Akrotiri, Cyprus.
  • Frequency = Several shortwave frequencies between 5422 and 16084 kHz.
  • Airdate = N\A.
  • Format = Numbers station.
  • Language = English.
  • Affiliations = Royal Air Force (Speculated).
  • Owner = MI6 (Speculated).
  • Sister_stations = Cherry Ripe.
Map of Akrotiri-en

Akrotiri, Cyprus, the believed location of the Lincolnshire Poacher's broadcasts and radio antennas.

"The Lincolnshire Poacher" was a powerful shortwave numbers station that transmitted from Cyprus from the mid-1970s to June 2008. The station gained its commonly known name as it uses 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 the island of Cyprus. Amateur direction finding linked it with the Royal Air Force base at Akrotiri, Cyprus, where several curtain antennas had been identified as being its transmitter. It consisted of an electronically synthesised English-accented female voice reading groups of five numbers: e.g. '0-2-5-8-8'. The final number in each group was spoken at a higher pitch. It is likely that the station was used to communicate to undercover agents (spies) operating in other countries, to be decoded using a one-time pad.

An Asian numbers station of identical format is believed to be broadcast from Australia, and nicknamed "Cherry Ripe". It uses several bars from the English folk song of the same name as its interval signal. Cherry Ripe continued to be on-air until December 2009. 

History[]

The precise date that the Lincolnshire Poacher began broadcasting is unknown; however, it is estimated that the broadcasts started around the early to mid-1970s. While numbers stations have existed since World War I (making them some of the earliest radio transmissions numbers stations such as Lincolnshire Poacher began appearing during the Cold War, when nations such as the Soviet Union and the United Kingdom needed to send messages discreetly to their operatives in other countries. However, after the Cold War, the number of numbers stations greatly decreased. The Lincolnshire Poacher remained operating after the end of the Cold War, and continued to be broadcast into the next two decades. 

In July 2008, the Lincolnshire Poacher stopped broadcasting. The last recorded transmission of the station was on 29 June 2008. It is believed that the station's sister station, Cherry Ripe, began to send broadcasts that used to be intended to be sent over the Lincolnshire Poacher station. This is believed to be true because the "Cherry Ripe" station used a very similar call signal, and broadcast its messages in 200 sets of five-number IDs.

Location[]

Although the usage of numbers stations has not been confirmed by any world government, amateur enthusiasts have traced the location of the Lincolnshire Poacher's signal transmission to RAF Akrotiri, a Royal Air Force base located on the Mediterranean island of Cyprus. The station is believed to have been operated by the British Secret Intelligence Service (MI6) and maintained by the Royal Air Force members that occupy the base in Cyprus. 

Broadcast schedule[]

The Lincolnshire Poacher was broadcast several times throughout the day, and was transmitted seven days a week, at various times and on various shortwave frequencies. This schedule was accurate as of January 2006, which is the most recent update to the broadcast schedule. All times are Coordinated Universal Time (UTC), and all radio frequencies in megahertz (MHz). 

Monday Tuesday Wednesday Thursday Friday Saturday Sunday
12:00 14.487
15.682
16.084
14.487
15.682
16.084
14.487
15.682
16.084
14.487
15.682
16.084
14.487
15.682
16.084
14.487
15.682
16.084
14.487
15.682
16.084
13:00 14.487
15.682
16.084
14.487
15.682
16.084
14.487
15.682
16.084
14.487
15.682
16.084
14.487
15.682
16.084
14.487
15.682
16.084
14.487
15.682
16.084
14:00 10.426
12.603
14.487
12.603
14.487
16.314
14.487
15.682
16.084
14.487
15.682
16.084
14.487
15.682
16.084
10.426
11.545
14.487
11.545
14.487
15.682
15:00 11.545
13.375
15.682
7.755
8.464
10.426
11.545
14.487
16.084
11.545
12.603
13.375
11.545
12.603
13.375
11.545
12.603
13.375
11.545
12.603
13.375
16:00 11.545
12.603
13.375
11.545
13.375
15.682
6.485
7.755
10.425
8.464
12.603
14.487
11.545
12.603
13.375
11.545
12.603
13.375
8.464
10.426
11.545
20:00 11.545
 
 
           

Cherry Ripe[]

Overview[]

Cherry Ripe Cherry Ripe was the nickname of a 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 thought to have previously broadcast from Guam. It consisted of an electronically synthesised English-accented female voice reading groups of five numbers, e.g. "3-5-7-6-1". It is likely that the station was used to communicate messages to undercover agents operating in other countries, to be decoded using a one-time pad.

Cherry Ripe had a more famous and much more active Middle-Eastern cousin, the Lincolnshire Poacher, which also used several bars from the English folk song of the same name as its interval signal.[1] The Lincolnshire Poacher had long been suspected as being operated by Britain and had been detected as emanating from RAF Akrotiri on Cyprus. Apart from the interval signal, the format and voice of the two stations was identical, though as of July 2008 the Lincolnshire Poacher appears to no longer be active. In September 2009, Cherry Ripe moved their transmitter to Humpty Doo, Australia.  In December 2009 Cherry Ripe also went off the air. 

Schedule[]

This schedule was accurate as of January 2006. All times are UTC, frequencies MHz.

Sunday–Friday
00:00 18.864
21.866
01:00 19.884
21.866
10:00 20.474
23.461
11:00 18.864
23.461
14.730
12:00 18.864
23.461
13:00 18.864
21.866
14:00 18.864
20.707
22:00 18.864
24.644
23:00 18.864
21.866

Yosemite Sam[]

Overview[]

This article includes a list of references, related reading or external links, but its sources remain unclear because it lacks inline citations. Please help to improve this article by introducing more precise citations. (March 2014) (Learn how and when to remove this template message) Yosemite Sam is the nickname given by DXers to a 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. The nickname is taken from the Looney Tunes character Yosemite Sam, whose voice is played as part of the unusual transmission.

The transmission series[]

The transmission begins on one of the frequencies. Ten seconds later, it is repeated on the next higher frequency, and so on for a total of two minutes. The entire pattern takes precisely two minutes, and always begins seven seconds after the top of an hour.

Each transmission starts with a data burst lasting 0.8 seconds, followed by the voice of Yosemite Sam exclaiming: "Varmint, I'm a-gonna b-b-b-bloooow yah t'smithereenies!" The clip is taken from the 1949 cartoon Bunker Hill Bunny.

The station disappeared on December 23, 2004, but returned during February 2005, on its old frequencies plus additional new frequencies, including those of time signals stations WWV and WWVH. Reception reports seem to indicate that the transmitter site is likely in the desert near Albuquerque, New Mexico, United States. The Albuquerque location suggests another relation to Looney Tunes: the phrase frequently repeated by Bugs Bunny, "I knew I should have taken that left turn at Albuquerque."

What is a 'data burst'.[]

In telecommunication, the term burst transmission or data burst has the following meanings:

  1. Any relatively high-bandwidth transmission over a short period. For example, a download might use 2 Mbit/s on average, while having "peaks" bursting up to, say, 2.4 Mbit/s.
  2. A telecommunications transmission that combines a very high data signaling rat with very short transmission times, and the message is compressed. That is popular with the military and in espionage, who both wish to minimise the chance of their radio transmissions being detected, a low probability of intercept (LPI) and low probability of recognition (LPR).
  3. In the 1980s, the term 'data burst' was used for a technique used by some United Kingdom and South African TV programmes to transmit large amounts of primarily textual information: they would display multiple pages of text in rapid succession, usually at the end of the programme; viewers would videotape it and then read it later by playing it back using the pause button after each page.
  4. Operation of a data computer network in which data transmission is interrupted at intervals.

Burst transmission, however, enables telecommunication between data terminal equipment (DTEs) and a data network operating at dissimilar data signaling rates.

Also see[]

  1. Radio
  2. The Cold War
  3. Secret service radio stations

Sources[]

  1. https://en.wikipedia.org/wiki/Numbers_station
  2. https://en.wikipedia.org/wiki/Burst_transmission
  3. http://www.cvni.net/radio/nsnl/nsnl015/nsnl15vs.html
  4. https://en.wikipedia.org/wiki/Lincolnshire_Poacher_(numbers_station)
  5. http://www.simonmason.karoo.net/page14.htm
  6. http://www.esquire.com/the-side/feature/numbers-station-07-31-08
  7. http://www.esquire.com/news-politics/news/a4903/numbers-station-07-31
  8. http://www.simonmason.karoo.net/page14.html
  9. http://speechificationaudio.s3.amazonaws.com/BBC_R4_Tracking_the_Lincolnshire_Poacher_24112006.mp3
  10. http://www.spynumbers.com/profiles/index.html?ENIGMA=E4
  11. http://www.cvni.net/radio/nsnl/nsnl147/nsnl147vs.html
  12. http://www.simonmason.karoo.net/page14.html
  13. http://www.simonmason.karoo.net/page14.html
  14. http://www.numbers-stations.com/E03a
  15. http://qrg.globaltuners.com/?q=cherry+ripe
  16. http://qrg.globaltuners.com/
  17. http://www.spynumbers.com/profiles/index.html?ENIGMA=E4
  18. http://www.simonmason.karoo.net/page14.html
  19. http://mt-utility.blogspot.com/2009/11/cherry-ripe-frequency-change.html
  20. http://www.archive.org/details/ird059
  21. http://www.numbers-stations.com/the-buzzer
  22. http://www.npr.org/templates/topics/topic.php?topicId=1074
  23. http://www.npr.org/programs/lnfsound/stories/000526.stories.html
  24. http://qrg.globaltuners.com/details.php?id=19667
  25. http://qrg.globaltuners.com/
  26. http://www.uvb-76.net
  27. http://www.securitygeneration.com/misc/uvb-76/uvb-76-activity-updates/
  28. http://www.wired.co.uk/magazine/archive/2011/11/features/enigma?page=all
  29. http://www.spynumbers.com/YosemiteSam.html
  30. http://qrg.globaltuners.com/?q=yosemite+sam "
  31. http://www.southgatearc.org/news/mar2005/ham_spy.htm
  32. https://people.ece.cornell.edu/land/courses/ece4760/FinalProjects/s2007/mc373_mag83/mc373_mag8#3/index.html
  33. https://morsecode.scphillips.com/translator.html
  34. http://www.robertecker.com/hp/research/morse-generator.php?lang=en
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