FSK: Russian native Airforce "Chayka" - telecode "Chayka"

Russian Airforce "Chayka" - telecode "Chayka"

Command/short message system, crypto, FSK-2.

• An example of the signal with frequency manipulation in 75Hz (this record was send us by PassTR)
• An example of the signal with frequency manipulation in 150Hz (this record was send us by Skif585)

Author: SergUA6

Band Width ~ 600 Hz

Low Range ~ 500 Hz, shift is possible, recieveing in SSB

Baud Rate 75, 150, 300, 1200 Hz

Count of Carriers 2 well visible frequency of manipulation on speed in 75Hz, but on 150-300Hz it will be problematic

Step between carriers 500 Hz

RX mode SSB

Sonograms:

pic.1 General view

pic.2 Speed of manipulation

pic.3 The repeated fragment

Diagrams:

pic.1 The exact frequency spacing

Russian Airforce "Chayka" - One of native Russian systems (equipment "Chayka") of interactions of military air forces and land stations.

It is old enough system, is probably still used today, because the transmission is encrypted and it is hard enought to identify it with high level of reliability.

An implicit signs of this system: the preamble presence, an alternation of tones with frequency of manipulation in the beginning, and also rare enough rating of frequencies 500 Hz. There is well visible presence of the repeating part, which is aldo vegin from the short preamble, on the third sonogram . Speed is 1200, it is most likely used on VHF a range (usual practice), other speeds are used for connection on HF. Sea-gull is the English translation for Russian word "Chayka:'.