Sheila, Alexa

After spending the afternoon on the arm locking, we spent some time looking at the COMM handoff.  (Plots coming in the morning...)

• By lowering the PLL gain (to lower the gain peaking frequency) we can get the COMM ugf to 35kHz.  (using PLL gain 19, CM in1 gain 27). 
• The 27kHz line from the end station is large in the COMM error signal as well. (so we wouldn't wat to use a high bandwidth in this loop anyway).
• We then went back to the nominal gains and had a look at the coherence with the OPlevs of our refl control signal, and the COMM control signal.  The ETM motion was higher when we did this, and it had coherence around the pitch resonaonce, the ITM didn't have much coherence.
• We measured some tranfser functions from pitch of the ETM to our control signals, and should be able to use this to make a projection of the frequency noise due to pitch of the ETM. 
• We noticed that the cavity transmitted power fluctuations were much smaller with the dither alignment servos off.  Suspecting clipping, we checked the single show bem position on the camera on ISCT1but it seemed fine. However when we engaged the dither servos the cavity transmitted spot was not centered on the camera.  After a manual realingment the cavity transmitted power seems much more stable. 

I am leaving the arm cavity locking, PRM parked and ITMY misalinged, and the alingment servos off.