Hola,
unid FSK 100/2000 system heard this morning (19 May) on 12129.5 cf starting from 0640, s/off at 0650. It sounds like an ARQ system, possibly from Russian Military. As far as I know, it seems that the signal is sent by an outstation to its main 'home' station, that in its turn operates in CIS 3x100 (VFT 3 x FSK-2 channels) on three correspondents. All these stations (main and oustations) operate in synchronous mode, usually not far apart in frequency.
Is there a name for that FSK system?
The recordered signal can be downloaded from here:
https://www.dropbox.com/s/wmkqgaw5s5ew7 ... z.wav?dl=0
ciao,
Antonio