Makai explained it exactly as I believe it to be. The IRD sends the appropriate voltage to the switch, so each switch output can be connected to the proper LNB for the channel selected. The relay clicking heard is the switches output being switched back and forth from one LNB to the other.

The reason I suggested swapping the coaxes at the switch inputs is to see if the dropouts switches from one set of channels to the other.

The benefit of using a power supply for the switch is that, especially with long coax runs, the switch receives plenty of power to operate the relays, but more important, that both LNBs receive the proper voltage at all times.

So, refering back to the original post, it sounds like the voltage being received by the LNBs is marginal, and at certain times, drops just enough that the LNB in question is being starved for power. The solution: get the power supply (wall wart) that the switch needs. (Jeff, is there a multiswitch?)

I noticed that Jeff didn't mention a switch, and only two receivers would not require one. With two receivers and a dual LNB, the setup is basically two independent systems: each IRD has its own LNB, so the cutout affecting both receivers is strange.

Larry
www.fineelectricco.com