Saab Grintek MHF-50 variant recorded on 8603.0 KHz/USB using the KiwiSDR located at TWR Kempton Park, South Africa: notice that 8603.0 Khz is believed to be one of working channels used by South African Navy.
The signal has a kind of "preamble" (Figs. 1,2) which is followed by the usual multimode waveform. This preamble consists of a short 75Bd/170 FSK
010100101001010010100101001010010100101001010010100101001010010100101
followed by a 120 sec long 1622 Hz tone which exhibits interesting markers each 12 & 1 seconds maybe to serve sync purposes.  |
| Fig.1 |
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| Fig.2 |
