Showing posts with label CIS-100/2000. Show all posts
Showing posts with label CIS-100/2000. Show all posts

17 July 2020

CIS-14 FSK 100Bd/2000 (CIS 3x100)

Interesting 100Bd/2000 FSK signal spotted on 16059.5 KHz (CF), most likely a Russian Governative transmission. This signal is not a separate one, actually it must be considered as part of the CIS 3x100 "system" visible on the left in figure 1. Indeed, the main station operates a VFT 3x100bd/1440 signal and works simultaneously three outstations which in turn run the FSK 100Bd/2000 waveform (outstations are usually not far apart in frequency).

Fig. 1
As well as the mainstation (VFT 3x100Bd/1140), outstations too use CIS-14/T-207 (as from the analysis of the demodulated stream in figure 2); all use the same checksum mode [0312].
Fig. 2
A clearer illustration of this "system" is visible in the spectrum of figure 3, the IQ recording of which was provided by my friend KarapuZ [1] who discussed the signal here.

Fig. 3

8 February 2016

CIS FSK 100Bd/2000, Russian AF (in this case)


this signal has been caught on 14555.0 KHz on USB at 0840 UTC and 1240 UTC (the latter from KarapuZ). It's an FSK modulation characterised by 2000 Hz shift and speed of 100 Baud. The user is proved to be Russian and the Morse mode seen in the upper tone, decoded using MultiPSK software (pic. 3), suggests the Russian Air Force since the call REA4 belongs to Russian AF HQ Moscow. By the way, before the upper tone keyed the signal were not transporting data. More likely the Air Force is not the only user of the waveform.

pic. 2
pic. 3