I've been noticing all night but not sure where from. Those nasty little lines seem to have come with a broad peak at 1040Hz. It's not the violin mode second harmonics (which ends at ~1010Hz).
A quick look at the summary page tells me that LVEA magnetometer noise started to get bad towards the end of November 17. No one seems to noticed it since we hadn't locked until last night. I've attached the spectrogram from the summary page from Nov17, 18 and 19 below.
When mysterious lines appear I'd like to think of beckhoff issue but I don't have a way to prove it. Worth checking maybe?
It seems to be related to newly installed RF AM monitor unit. RF AM monitors are "quiet" in that it's not glitching but the coherence is clearly there.
RF45 in-loop sensor (RF45_AM_ERR and CTRL) doesn't seem to see anything, but the out-of-loop sensor (RF45_AM_AC) and RF AM monitor both ways (RF9_AM_AC and ERR) are highly coherent with DARM.
