"OSCAR" navsat series telemetry on 149.985 MHz

Sven Grahn

The spectrogram below was obtained from OSCAR-27 on 15 January 2000. This kind of spectrogram is obtainable with the receiver in AM or narrow-band FM mode.

This satellite is part of the later Transit series of navigation satellites launched in pairs as "Stacked Oscar On Scout" [SOOS].

The signal is quite bewildering. There are several subcarriers below 1600 Hz, perhaps four. There seem to be two subcarriers at 2400 Hz and 3300  Hz. They do not really seem connected to the IRIG FM/FM subcarrier standard frequencies

Click on the spectrogramme to hear the signal - familiar to the experienced space listener.

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