|Emission mode||FSK, 200 bd, 1000 Hz, ACF=288|
|Known counterpart stations|
F06a is a variant of the Russian intelligence broadcast system F06. While it uses the same modem protocol, it sends completely different payload - ASCII text with a large chunk of data lost due to regular omission of 4-bit chunks. However, no plaintext has been encountered, only 5-digit and -letter groups. It has only been heard in unscheduled transmissions.
The data itself is preceded by a binary header containing the following information: (here represented hexadecimally)
- The first group is always 0000.
- The second group is the size in bytes the transported data would have had without corruption.
- The third group is always 0303.
- The fourth group and the first byte of the fifth contain the group count spelled out in ASCII digits. (0x30 .. 0x39)
The messages delivered always consist of a header with five 5-digit groups (same format as F01), two line breaks, and the groups formatted into 10 groups per line. The line endings used have mostly been CRLF, with one exception using LF.