Fleet Broadcast is a 16 channel 75Bd multiplex transmitted from SATCOM satellites on 250.450/550/650 MHz.
Modulation is DBPSK 1200Bd, to receive it you need receiver with 2KHz filter and SSB mode.
Channel #0 is used for synchronization, other channels are usually filled with pseudo-random crypted data.
Sometimes KG84 messages are transmitted. So far no plaintext was ever seen on Fleet Broadcast...
- On top there is status line like [S-r-Ki-i-i--iKii]
This represents state or detected content of channels as:
- S = SYNC
- r = reversals (1010101010 pattern)
- K = KG84
- i = idle/constant 1 or 0
- - = unknown
- Also sync quality (should be 100% all the time with good signal) and increasing frame counter (resets on resync)
- At bottom there is status log with info about KG84 and program status messages
- Q = exits application
- S = toggles saving of raw bit stream to files
- +/- = Tune demodulator frequency, demodulator have AFC and will adjust once tuned -/+100Hz or so
Download: fbr.zip (41kb)