Loaded these this morning after getting the new .mat files Hugo built yesterday.  A few minor plotting difficulties and then after conferring with JeffK, loaded the filters at 1228pdt.  Opened the HEPI loops, loaded the filters and turned them back on all with the ISI Isolating (Lvl1.)  Silly me, I didn't take a DDT look before the switch altthough I had done this before a week+ ago and I could see the ugly zero pretty easily then; the second plot in 13810 is a good place to see this.  I undamped/unisolated the ISI and looked with DTT and like the long commissioning transfer functions, you really can't get any coherence in the area but at least the amplitude doesn't show the deep zero.  Next step would be to run the longer TF on the HAM4 ISI--later.