OK, so I finally got around to finishing the setup for my DirecTV multi-switch. Last time around, I wired the second cable. This time, I bought the diplexers and multi-switch.
I got Terk products from Circuit City, and I am pleased with them. I was going to get one 3-4 multi-switch (that's three inputs and four outputs) and three single diplexers (one for each receiver), but then I saw the dual diplexer.
The dual diplexer takes two sat signals and one CATV signal, just like the multi-switch, and outputs two combined signals (instead of four). So I just reversed it: it takes two combined signals from the multi-switch, and splits them into two sat signals and one CATV signal. Because it is not actually splitting the sat signals, but passing them through and combining/splitting with the CATV, it is OK. And it works nicely.
So I have the multi-switch in the basement, with the sat and CATV going in. Then I have three combined signals coming out, one going upstairs and two going downstairs. The two downstairs go into the dual diplexer, and then into the VCR and the two sat inputs on the TiVo. The other signal goes into the bedroom, into a diplexer, and the sat goes into the other receiver, while the CATV is split, going into the TV and then to the den, for the cable modem.
I was worried about the cable modem, but it seems just peachy in this setup.
I had some troubles, though. First, the diplexers came with this "DC Block" dongle, and nothing on the web site or in the package said exactly what it was for. It did say that the diplexers allowed DC signals to pass through, I think for powered antennas. So after a lot of trial and error, I discovered that if I did not have those dongles connected on the CATV out, that the sat signals wouldn't work at all (which makes sense somewhat, but they could have told me). And one of the dongles was broken; luckily, the multi-switch came with one, and it didn't seem to be needed for the CATV in.
My other problem was that one of my long cables from the sat was kinda busted at one end. I had a lot of extra length to work with, but have you ever tried to put a fitting on the end of a heavy-duty coax cable with only pliers and a knife? It works, though. I figure if I can attach my dual LNB to my dish arm with an electric jigsaw and duct tape, I can make this cable work without the proper tools.
So it all works, and I ain't gonna touch it again. I couldn't even if I wanted to, because my fingers are killing me with all the loosening and tightening of the coax