27 June 2015

Unid FSK-8 + PSK-2 1200 Bd (prob. AX-25)

Recordered this morning on 19304.0 USB (central frequency 19305.0) starting from 0937z until 1020z (s/off). The trasmission  heard consists of a series of short messages in PSK-2 1200 Bd (as well as some short bursts) along with 9-tones intervals. Sometimes a PSK-2 100 Bd preamble is sent. 

9-tones and PSK-2 1200 Bd insertions
PSK-2 1200 Bd, carrier ~1060 Hz
the 9 tones, top and bottom @ 7dB higher

PSK-2 100 Bd preamble
The transmission ended with a short CW/Morse message, decoded as "RFM U NIL SK 73" (more likely the '73' stands for greetings, as in HAM world).

The same waveform has been reported in radioscanner.ru:
and it is still un-identified.

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