Just had a ~3min drop from OBSERVING due to SQZ, but it cameback automatically.
Did notice the SQZ_OPO_LR node has the familiar User Message:
"pump fiber rej power in ham7 high, nominal 35e-3, align fiber pol on sqzt0"
It's been trending up the last 5 days when it was last touched up on 3/26 (alog83570). Looks like it moved above 0.35 counts at 10am (local time) this morning. See attached.
It's been a few minutes and one can see H1's range took a step down about 6Mpc after this SQZ drop.
Camilla, Sheila.
The drop was because the OPO PZT ran out of range, see t-cursor on attached plot. It's a known issue that the SQZ angle (and alignment) changes with different PZT1 voltage.
It seems like that the sqz angle was set for 60-70V and was bad once we relocked at 100V. This would have been improved by taking SQZ_MANAGER to SCAN_SQZANG_FDS so it can find the best sqz angle again. If we were running the SQZ_ANG_ADJUST servo, this may have improved itself as you can see the ADF reported SQZ angle change at the time.
With the higher (19 vs 11) NLG 83665, the range and 350Hz SQZ (yellow BLRMS) does seem to be improved, but the high frequency SQZ did seem to be less stable as we thermalized.
