This afternoon Terra and I had a few hours long lock durring which we injected white noise in the ISS, and the IMC PZT (alternating between PIT and YAW). We found that we were able to reduce the jitter coupling by almost 8dB by moving the POP A offset for PIT, which also seems to have reduced the intensity noise coupling slightly (2 dB).  While the couplings did drift as the interferometer thermal state changed at the begining of the lock, the improvements were reproducible with an on off test.  

We started by moving SRM in both pit and yaw, but saw no impact on the jitter coupling that was reproducible with an on off test, which is different from what was seen in alog 25654 and 25657.  The POP PIT offset changed from 0.24 to 0.47.  Durring the move POP 18 improved by about 10%, while the recycling gain improved by about 1%, but neither of these were at their best in the final location. We started trying to move the yaw offset, which looks like it needs to be moved closer to 0, but lost lock due to a bounce mode. 

In the first attachement, you can see a comparison of the DARM spectrum before and after the POP move. The second screenshot shows comparisons of the couplings before and after. The third shows trends of powers durring the change, and the awg set up for the excitation.