Hi - I am new to this forum, I wanted to ask a question about the fine frequency drift of the GOES-16 and 17 satellites. I have been monitoring what I believe to be the GOES DCS rebroadcast at 1.6797 GHz using an Airspy R2 with a Rubidium atomic clock stabilizing it. At high FFT resolution I can see what looks like the expected Doppler shift in transmission frequency due to the satellite approaching and receding from my location during its elliptical orbit, which amounts to about 4-5 Hz per day. However, I have noticed that there appears to be another signal riding on top of this Doppler signal of about 1.5 - 2.5 Hz with a period of about 12.4 hours. Has anyone else ever seen this before? It appears be be a lunar effect, like a tidal effect, but I am not sure why I would be able to see a tidal effect in the transmission frequency of a satellite of this magnitude. Any idea on what would cause this?
thanks - Doug
thanks - Doug
