21 April 2015

Japanese Military 8 frequencies: 2 FSK channels, cross-schema reduntant

This signal was seen on 16553.5 KHz/USB around 1900z  and - at that same time - on 12384.5 KHz/USB by my friend Mauro IK2GFT from Milano:


It is composed of 8 distinct channels, 300 Hz spaced and 100 Baud as symbol rate. The signal uses about a 2400 Hz bandwidth.
The signal consists of two independent FSK-2 channels which are doubled according to a cross-schema (tones separation too is doubled), so the 4 FSK-2 channels (8 traces) that are visible in the sonogram/spectrum. According to the analysis performed by radioscanner group, all the four channels use the Manchester code and, since the time offset between the first and second channel, they are formed using OFDM technology.

more info here (signals.radioscanner.ru) 



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