As I said earlier, DIRECTV won't give you much that will help.
Yea, you're getting closer & pretty much on the mark. It sounds like your having D install the SWM 3LNB which is a slightly different configuration than already having an AT/U9 with 4 coax outputs that go into the SWM8. I don't have the schematics for the SWM-LNB so I'm not 100% sure how or where they diplex in your OTA feed but it would have to be upstream of the splitter or you would only be getting your OTA's off of the good coaxial cable. If you get a great installer who's done some of these things it should go smoothly; you get the deer in the headlights tech & you'll have to reschedule. If you weren't getting the SWM dish from DTV it sounds like you could do all of this yourself with the help of this board. I followed the directions to the letter & listened to the pros here for help (one emailed me the full schematics) & the Receivers all switched over to SWM without a hitch. It also gave me a chance to replace & redirect all the old coax (besides the buried stuff) just the way I like it instead of their install. Bottom line, you're on the right path & you may encounter a hitch or two along the way but in the end you'll love it. As an aside (& keep in mind I have plenty of OTA signal with a preamp/distribution amp setup) you can use a normal dipler on the OTA coax that comes from the SWM diplexer & feed OTA to both the AM-21 & you're TV. I know you lose a little signal every time you make a splice or use one of these connections but the loss is minimal if you have amplified OTA feeds. Should your OTA stations start to fade in & out or checkerboard themselves you'll just have to remove the second diplexer because you don't have enough signal. If it works you have OTA on your receivers as well as your TV should you ever want to use that input to watch locals or your box goes bad.
