Today we had two locklosses from the 80 kHz PI on ETMX (69800) in addition to one last Friday (69759), all occuring at Hour 2:30 into the lock. I compared today's 10.4 kHz HOMs with a previous long lock from May 13, when I think we had finished TCS tuning and stayed on at 76W. I didn't see another solid 10+ hour lock since then. Times used for comparison here.

Previously, we have ID'd the pointier HOM peak as ETMY, and the blunter peak as ETMX. Comparing today to 1.5 weeks ago, I think the HOM on ETMX (blunter) is now noticeably lower in frequency -- maybe that is why this 80kHz PI is now ringing up? Previously, it looks like we lowered the EX RH slightly to avoid this 80 kHz PI (eg. 68166, 68165). Maybe we ended up just barely stable after the last EX RH TCS change. While the EX VEA temperature looks pretty stable, there have been some temperature excursions in the last couple week, maybe this is related to the 80 khz PI showing up and the lowered ETMX HOM peaks? And now, possibly with the EX VEA is heating up b/c of summer (even though its temp looks stable), maybe it's worth trying to lower the ETMX RH a bit again, to further avoid this PI.