I have seen this multiple times, and it is not RF interference as far as I can tell. It looks like the Shake may be self oscillating. You can see it starting for a short period at 2134, then the trace goes back to normal. I see nothing in the logs. Any help appreciated.
RSH.RBE98.2021-04-13T10_42_53.logs.tar (2.9 MB)
are you referring to the similar-sinusoidal track that starts at approximately 21:34 on your helicorder? Because I cannot seem to find anything at the 21:15 mark that you have indicated.
Yeah, counted wrong. It’s early. I corrected my original post. Yes, it is the sinusoidal waveform that appears for a few minutes.