Reports until 01:00, Saturday 15 August 2015
H1 ISC (ISC)
gabriele.vajente@LIGO.ORG - posted 01:00, Saturday 15 August 2015 (20547)
CHARD and A2L

The low frequency sensitivity (below 50 Hz) was coherent with CHARD PIT and YAW. I tried to retune the A2L, first using Hang's script: I had to fix a bug in the function call (number of steps passed as double instead of integer). The script ran, but made the coupling much worse. So I tried to measure by hand the couplings, injecting lines at 21 Hz. A the end of the day I got a performance similar to what I could get reverting to the A2L coefficients of one day ago. So I reverted to the old coefficients.

At 0:53 LT I reduced CHARD PIT and YAW gains by 20 dB, and as expecetd the noise got better. However, the low frequency is non stationary.