J. Kissel, S. Dwyer

After both Keita and Sheila had recited the H1 SUS ETMY's measured highest vertical, "bounce," mode frequency was 9.7305+/-0.0002 [Hz], I was glancing around at the various notching done in the control filters for H1 SUS ETMY. I'd found that the optical lever's pitch loop had a bandstop filter of
ellip("BandStop",4,1,60,9.7,9.9)ellip("BandStop",4,1,40,13.4,14.2)gain(1.25893)
i.e. just missing the ETMY frequency. Thus, we adjusted the filter to better match 9.7 [Hz], i.e.
ellip("BandStop",4,1,60,9.6,9.8)ellip("BandStop",4,1,40,13.4,14.2)gain(1.25893)

This reduces the gain of the loop at 9.73 [Hz] by a factor of 76.9231 (37.7 dB).

This was done well before locking activity go started this evening. The pitch loop remains on. As with the DARM DAMP filters, this change was individually loaded into the bank.