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M08a

Enigma ID M08a

Name
Frequencies 7555, 8010, 8097, 8136
Status Active
Voice N/A
Emission mode ICW
Location Cuba
Activity pages

Download audio sample

Known counterpart stations V02a

M08a is ran by Cuban Intelligence Directorate (DGI).

M08a always sends three fixed-length messages of 150 groups, and uses the following letters to represent digits: ("cut numbers")

0 1 2 3 4 5 6 7 8 9
T A N D U W R I G M

Format:

Preamble Message #1 Message #2 Message #3 Outro
DIRTA AGIGN NTTNN DIRTA BT BT BT NRWAW UGDTU UNTUI ... AR AR AR AGIGN BT BT BT DUURW RUTUW DUUTU ... AR AR AR NTTNN BT BT BT TWTGR TRARG RUDUW ... AR AR AR SK
Three 5-figure message headers First message header   Fixed-length message of 150 5-figure single groups, with an extended pause every 10   Second message header   Fixed-length message of 150 5-figure single groups, with an extended pause every 10   Third message header   Fixed-length message of 150 5-figure single groups, with an extended pause every 10    
Repeated for 3 minutes Repeated 5 times       Repeated 5 times       Repeated 5 times        

The first 4 digits of the headers represent the message ID, the last digit is always either 1 or 2 (A or N).

Operation habits

M08a has three time slots, 14:00, 20:00 and 23:00. It usually transmits daily, but often skips days.

UTC Mon Tue Wed Thu Fri Sat Sun UTC
14:00 8096 8096 8096 8096 8096 8096 8096 14:00
20:00 7554 7554 7554 7554 7554 7554 7554 20:00
23:00 8009 8135 8009 8135 8135 8009 8135 23:00

The 14:00 and 20:00 slots are sent at the speed of 15 WPM. 23:00 is usually 20 WPM.

M08a transmits out of an LSB transmitter with 1 kHz audio tone, and a computer running Windows XP is used to create the audio. Mistakes are frequent. Most often it's HM01 either replacing M08a completely, or going on top of it. The computer running the transmissions has been heard restarting halfway through the broadcast, leaving audible shutdown and startup sounds.

The 20:00 slot is notable for sometimes carrying V02a on one Thursday of the month, usually last or first. That station is not otherwise active.

On Saturday and Sunday, if M08a does transmit, it always is the same set of three particular messages, with headers AGNRN NNWTA DWTNN (18262 22501 35022).

History

M08a started in January 1997, replacing the earlier format M08.[1]

In the past M08a had many different schedules, some using MCW mode. The messages were usually repeated an hour later, and also on several other linked time slots. The last digit of each header used to signify which repeat of a particular message this transmission is - 1, 2 or 3.

Much has changed in 2013, when M08a's voice counterpart V02a became almost extinct in favor of HM01. The three daily schedules at 14:00/20:00/23:00 remained the only M08a time slots in operation. Slight format change also happened - now the three headers at the beginning are repeated in a continuous string for three minutes, rather than with a short pause between the three.

References

  1. ENIGMA Newsletter #12 (January 1997), p. 17 - read a scanned version here
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