Inline diode fix - cause and effect
My problem was my C band would not switch to vertical polarity. All my Ku feeds switched with no fail. I could switch my C band to V by entering tune up screen and select a V TP, then selecting a diseqc port other than the one with the C band feed. This removes voltage from the C band feed*. Then reselecting the proper port. I first had this problem with my Pansat 9200. When it was replaced with the S9, I removed the "diode" and had the same problem. Reinstalled the "diode" inline and no more problems. I jury rigged a test where I could feed an adjustable voltage to the LNBF's and found the Ku lnbf's would all switch to Vertical as soon as voltage dropped below 15vdc. The C band LNBF would not switch to Vertical until the voltage went below 14vdc. With the receivers, 9200 and S9, supplying 14.4vdc the C band LNBF could not switch. A diode will drop ~.7vdc. With it inline it drops the LNBF supply to ~13.7. which allows the C band LNBF to switch. All LNBF's, C and Ku, would switch to Horizontal with voltages going above between 15.6 and 16.5 vdc.
*With the S9, I could have done essentially the same by just selecting LNB Power Off, instead of diseqc port changes. Don't think I had that option with the 9200.
I have no capacitor in mine. A 1N4000 series has plenty of internal capacitance to pass L band in 75? coax. I note no loss, lowered Q on any satellite with it inline.
My S9 will drop Q reading when moving my BUD via diseqc in the Antenna Setup screen. Changing TP back and forth brings it back. Haven't investigated if it's only S2 TP's or not. Don't think anything external could fix that.