12 May 2023

TADIRAN HF modem running in scrambler mode (2)

Fig. 1

Tadiran/ElbitHF modem, probably the HF-6000 model, running in COMSEC mode using FSK 125Bd/300Hz Digital Coded Squelch (DCS) and scrambled voice-comms. The FSK segmentes (the DCS part) sent during the scrambled voice-comms have a speed of 125Bd and 300Hz shift, ie same parameters of the initial F7B (apparently MFSK-4) waveform, and cosists of a 160-bit period bitstream (Figure 2).

Fig. 2 - main DCS parameters

 It's worth note that the transmission was sent using LSB (Figure 3).

Fig. 3

https://disk.yandex.com/d/novPamUmQksXmg

1 comment:

  1. I've caught some (by-passed scrambler) voice on 31 May 2023 and with the help of some guys we found that it was Slovenian language, it's rare to catch Tadiran equipments on LSB so I assume the next tfc spotted in LSB will be SVN MIL? again.
    73

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