SUMMARY: Have been locked for almost 4hrs and in the last hour noticed our range slowly taking a dip in range over a 30min span (went from 112Mpc down to 102Mpc!). Cause for the dip was a noticeable line on DARM which was sweeping between 65-120Hz (along with a few of its harmonics). It's gone now.
TIME Of Event: 13:27 - 14:02utc Stopped abruptly at 14:02.
DARM BLRMS Striptool really show the effect. H1 had a normal glitch and right after the glitch the the 60-100Hz band remained elevated. 100-450Hz band would go up a little due to the harmonic, but when the fundamental swept above 100Hz, then the 100-450Hz band became the noisiest. (nuc6 Note: 100-450Hz has been off-scale on this StripTool, so I increased the vert axis and saved the file).
I took power spectra of a quiet time (blue) & during this noisy time (red) & you can clearly see the fundamental and it's harmonics. But like I said, it was noticeably sweeping across DARM (I seriously looked at the CDS Overview for any excitations, but everything looks green in here!).
Attached is a screenshot showing the power spectra, DARM BLRMS StripTool, & the BNS Range.
This is the squeezing wandering line again. See alog 48892. For today, h(t) and the relevant SQZ channel are shown below.
It looks like Jenne recommended that the noise eater be turned back on because the squeezer wouldn't lock (alog 48985). It's not clear whether it can be turned off when the wandering lines appear - maybe she can clarify.
Oh wow, thank you for the quick reply‘s this morning! And I agree maybe we can wait for Jenne to give us input about the Noise Eater.
I'm seeing this as well. Noise eater (squeezer) is currently ON.
Patrick was having a problem with the TTFSS on the squeezer not locking on Saturday night, so I (in the absence of other ideas) suggested turning on the noise eater to see if that would help, thinking that maybe the noise that it is supposed to suppress was a bit high, and that was causing problems for the TTFSS. Turning the noise eater on seems to have let the TTFSS lock, and Patrick was able to get back to Observe.
In hindsight, probably it would have been better to have Patrick turn the noise eater back off once the squeezer was locked.
Also, Daniel mentioned today that it's not clear that the noise eater should do anything to help the TTFSS, so maybe there was something unrelated going on? In any case, we should run with the squeezer's noise eater off (which it currently is).