19 October 2015

THALES: Système 3000 robust MFSK-8 and TRC-177x family serial modem

just heard this morning on 16256.5 USB at 0857z, probably source French Military.
The MFSK-8 waveform uses the same tone library as 188-141A/B 2G ALE but callsigns are limited to a maximum length of 2 figures only and can also be used as a robust-data mode. Aurally and visually it is easily mistaken for a normal ALE since the 250 Hz spaced eight tones and 125Bd speed. 
The serial-tone waveform more probably belongs to THALES TRC-1752 modem, has all the characteristics inherent STANAG-4285 (serial tone carrier 1800 Hz, speed 2400 baud and modulation PSK-8) except for the phase constellation of the preamble: a 'special' with 5-ary constellation maybe for receivers tuning purposes. ACF is 106.6 ms.TRC-1752 modem seems to be replaced by the HF Multi Mode modem TRC 177X family.  

the two combined THALES waveforms
serial tone ACF

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