About an hour ago, I noticed that our sensitivity degraded significantly in the bucket. This brought our range down to about 20-30 Mpc from the 50+ Mpc we had been at.
Glancing up, I noticed that the RF45 spectrum looks atrocious. I'm not at all sure what is going on, but it is very bad, and changing with time.
In the attached screenshot, I have the DARM spectrum, the RF 45 and RF 9 spectra, as well as the RF coherences with DARM. The colors are the same in each plot, with the start times of the data indicated in the DARM legend. Dark blue is a good time, when our range was good. Pink and green and red show different times when there was a weird peak in the RF45 spectra. Brown and light blue are intermediate times when the RF45 is elevated, but not peaky.
I don't know why this would have anything to do with the new barrel connector that Richard et al. put in earlier today (alog 30375), but maybe I'll go jiggle it.
EDIT: Before any jiggling, Terra Patrick and I notice that it's steadily getting worse :(
Did some jiggling while Patrick and Terra helped me watch the RF45 and DARM. I'm not really sure what cable/connector Richard is referring to in alog 30375, since I didn't find any RF45 cables with a barrel-through. But, I tried tightening all of the RF distribution N-connectors both on the CER side of the patch panel and the LVEA side. No dice. The noise keeps jumping up and down, so it's hard to say if I did anything, or it's all just coincidence.
At one point the noise basically went away while (I think) I was touching the connector for the RF18 on the CER side of the patch panel. But, (a) I have no idea why that would affect anything, and (b) it was totally non-repeatable.
Noise hunting at this point is futile, and the data can't possibly be useful for testing analysis pipelines, but Terra is still getting useful stuff out of the lock at high freqs and for other PI work, so at this time I am not going to call and consider cancelling the owl shift.
When this next occurs, and it will, Try moving the gain slider on the EOM driver and see what this does if anything.