Well, I called and asked DirecTV what switch I should use, and they said any 2x4 switch, so I went to radio shack and picked one up there. Even though the box clearly stated that it was for a dual LNB dish, the saleskid said it would work. I figured I could bring it back if it didn't work, and I took it home to try.
Well, as long as I stayed on SD channels, it seemed to work ok. If I tuned to an HD channel, I got a message from the hdtivo that it had 0 signal on reciever #2 etc.
So I called DirecTV again, and after relaying my problem history, was told that I just need 'any old 4x8'. I have my doubts about this.
PArt of the problem is that I already have two cables going to the living room, which are run through the walls, and I don't have a good method of running new cables to the living room without running surface cables outside, which I would SERIOUSLY like to avoid.
I guess part of the confusion comes from the fact that there is already a multiswitch of some kind in the dish; does this mean that I need a special downstream multiswitch?
I have a diagram which I will post momentarily which may help explain what I'm looking for.