priyom.org

SK01

Enigma ID SK01

Spectrum image SK01

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

Flag_Cuba

Activity pages

Download audio sample

Known counterpart stations V02a, M08a

SK01 was run 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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