J. Kissel

Taking the template from a few days ago (LHO:57651), and refreshing my memory on previous QUAD's in-air measurements prior to BRD tuning (e.g. LHO:40534 for 2018's ETMY and LHO:40149 for 2018's ETMX), I've zoomed in, averaged for longer, at higher resolution, and confirmed that the 2020=2021 H1SUSITMY's new highest vertical ("bounce") and roll modes are 
    Mode     Frequency (Hz)
    V4       9.76416
    R4       13.85600
where the frequencies were measured with 25 averages at 0.5 mHz resolution (FFTs = 2048 sec, ENBW = 0.732 mHz, w/ Hanning Window). Recall that these frequencies when suspending the former ITMY test mass were 9.816 Hz and 13.898 (1 mHz resolution, see LHO:40098) 

See attached screenshot for proof!

I'll "re-tune" the QUAD's BRDs to these frequencies. I put "re-tune" in quotes because the target tuning precision, defined in  is "within +/-1% of the measured frequency," or "+/- 0.09 Hz for the bounce and +/- 0.13 Hz for roll." Now, since the BRDs are *already tuned* to meet target frequencies of 9.831 and 13.93 Hz in LHO:38659 (10 mHz resolution, notably different than 1 mHz in-vac results quoted above), and for the two BRDs, I achieved [9.863, 9.906] and [13.938, 13.875] Hz (31 mHz resolution). That means the 1% lower limit would [9.773, 9.816] and [13.808, 13.745], which comfortably includes the *new* measured ITMY frequencies. So be "re-tune" I mean try my darnedest not to change anything and just confirm that the frequencies are still were I tuned them to be.