I have the same prob with the DMX c band lnbf. It seems this lnbf is really picky about the voltage for vertical polarity. I have tried with and without a disqc inline, no change. I left my "Cheap 'n' Dirty" fix inline that I used to correct the same prob first experienced with the Pansat 9200. I just mounted a couple of chassis "F" connectors on a aluminum box and soldered the diode to the center pins. band side of diode to dish/lnbf. Receiver lnb input -->]-- 1n4001 diode --- lnbf. I don't experience any sig degradation.