Somehow the hypothesis has been that the peak in the MC OLTF is the structure in FSS and we should be able to mitigate that guy if we retune the FSS notch.
That was attempted today, but the problem is that the peaks the FSS notch is notching out are at about 780 kHz, and MC "peak" we're talking about is a rather broad thing at around 710 kHz. We could move the FSS notch to there, but if we do that the FSS structures are almost totally out of the notch. See attached. Note that the MC OLTF was measured without Evans Notch (TM).
It's clear that the "peak" we're talking about is not the FSS peak per se, it's either a simple gain peaking or something that is not there in FSS. Keeping Evans Notch (TM) sounds fine to me, but if somebody feels the need to put move it out on the option board in the common mode board, please feel free.
Correction: Both the OLTF of MC without (middle) and with (bottom) the notch in the MC path are in the plot.