16 December 2020

Unid MFSK-13 system

Unid MFSK-13 system running at different speeds (31/62.5/125 Baud) and intervals (125/250 Hz) spotted on Twente WebSDR on ~10625, ~9091, ~7779 KHz/USB thanks to friend radiotehnikaT101

Fig. 1
Fig. 2

It's to be noticed the quick change of the waveform in the 10625 KHz recording (from 31Bd/250 to 125Bd/126): maybe the first part could be the "call" segment. I tried a rough demodulation by replacing the Hex characters (0...C) with their binary value (0000...1100) but I didn't find anything interesting in the bitstreams except some patterns in the 31Bd/250 segment (88/176 bit period).
Most likely  these are experimental transmissions in the network of the Ministry of Foreign Affairs of the Russian Federation. 

Fig. 3


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