help. hooked 721 to a location with one coax and very difficult to add another coax so the dpp44 with a splitter is a major savior. did the software thing and all works well EXCEPT----- I had a 508 there and diplexed to the TV down stairs. Now when I put the diplexer in the 721 does not see the satellite anymore. Has anybody used the dpp44 plus splitter with a diplexer?