priyom.org

SK01

Enigma ID SK01

Spectrum image SK01

Name
Frequencies
Status Inactive
Voice N/A
Emission mode AM
Location Havana, Cuba
Activity pages

Download audio sample

Known counterpart stations V02a, M08a

SK01 was ran by Cuban Intelligence Directorate (DGI). Succeeded by HM01 in 2013.

The name SK01 was introduced as a blanket designator for all digital modes used by DGI since late 2006. In late 2007, they settled on Redundant Digital File Transfer (RDFT), a mode initially created for use by ham radio operators. The program used by SK01 to create the transmissions was DIGTRX.

SK01 carried files with 8-digit file names and extension ".txt". The contents were encrypted binary data.

SK01 ran on hour-long schedules in AM mode, during which one file was conveyed. The file would have been transmitted every exactly 5 minutes, with only a blank carrier between the repeats.

Previous modes

Prior to adoption of RDFT, the modes previously used by SK01 were BPSK31, QPSK31 and BPSK220F. In early 2007, the format was:[1]

  1. 11111 followed by a space and the current date in format DD/MM/YYYY (repeat all thrice)
  2. 5-digit message header repeated five times, then 150 5-digit groups
  3. "+ + +"
  4. 22222 followed by a space and the current date in format DD/MM/YYYY (repeat all thrice)
  5. 5-digit message header repeated five times, then 150 5-digit groups (both different than the previous message)
  6. "+ + +"
  7. 33333 followed by a space and the current date in format DD/MM/YYYY (repeat all thrice)
  8. 5-digit message header repeated five times, then 150 5-digit groups (both different than the previous messages)
  9. "+ + +"

In mid-2007, the format changed to the following:[2]

  1. 11111 followed by a space repeated 10 times
  2. 5-digit message header repeated 10 times
  3. 150 5-digit groups
  4. 22222 followed by a space repeated 10 times
  5. Repeat all of the above thrice, but with different headers and messages

References

  1. Ary Boender, Numbers & Oddities #113 (January 2007) [accessed December 21st, 2014]
  2. Ary Boender, Numbers & Oddities #115 (March 2007) [accessed December 21st, 2014]
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