sheila.dwyer@LIGO.ORG - posted 12:02, Tuesday 21 November 2023 - last comment - 15:24, Tuesday 21 November 2023(74334)
added cable to 3MHz local oscillator
I added roughly 5 meters of LMR 195 to the cable sending the 3MHz local oscillator to the demod for the OMC 3MHz signal. This should add roughly 21ns of delay, or roughly 23 degrees of phase for the 3MHz signal.
We are hoping that this will shift the turn around point of the ADF sqz angle readback so that our operating point is at a better place to use this readback to adjust the sqz angle. (for background see 74256
This means we will need to retune the SQZ angle before we to observing today.
The SQZ angle will have to be retuned when we relock today. To do this, from the sitemap choose SQZ > SQZ overview to pull up the scren shown in the screenshot. You can then adjust the slider circled in red (H1:SQZ-CLF_REFL_RF6_PHASE_PHASEDEG) looking at the FOMs on NUC33 to tune the squeezing. Try to minimize the black trace on the spectrum on the bottom of NUC33.