I tried a few things to look around for a useful signal for SRM ASC at 50W, and had no luck. 

I am pretty convinced that there's no signal that's useful in REFL45 for the SRM.  I couldn't get rid of the ~0.16 Hz oscillation that we see in the PRC1 and PRC2 control signals, which I tried in an effort to see something better in REFL45.  (I tried adding res-gains in both PRC1 Pit and PRC2 pit, to no avail.  Out of loop motion as measured by POPB didn't change.)  I eventually tried "cheating" by lowpassing the REFL45A pitch and yaw I signals (these are not in-loop for anything), but there's really nothing at all there for the SRM.  I also tried moving SR3 (after disabling the cage servo), but that also didn't really have a good signal anywhere but AS36B.  Both SRM and SR3 have an okay signal in AS36B, but I was hoping to find something that wouldn't leave us back in the "sensing matrix of the day" regime. 

Interestingly, the noise at high frequencies seems to get better when POPAIR90 is higher and rattier.  I'm not sure right now why a misaligned SRC would help suppress frequency noise. 

I tried Nutsinee's CSOFT offsets from the other night (alog 30085), and while they do seem to improve the sensitivity in the bottom of the bucket, they noticeably reduce the power recycling gain.  I tried a few other offsets, but I think 0s everywhere for the SOFT loops is about the best in terms of power buildup.  I was running a2l at each offset, and the calibration lines at 330 and 1100 Hz were roughly constant, so I don't think I was fooling myself too much.  So, why do we get better sensitivity in the bucket with lower recycling gain (28 rather than 30)?  I see the buildups go down in the arm transmissions as well as POPDC, so it really is a reduction in the recycling gain. 

Note to self for the morning:  Were good / bad range times really correlated with times when the AS90 dark offsets jumped?  It vaguely seemed that way, but I need to check.  The AS90 signal would occassionally pop up and be visible on the front tv striptool, even though it should be too low for that with the beam diverters closed.  It was sudden jumps, not obviously related to alignment changes, so I think it was dark offset changes.  If that's true, do we need to finally figure out why the electronics at the HAM6 rack are so finicky?  No one was out in the LVEA, so I'm not sure why the offsets were changing.