I have a UHF/VHF antenna and my Dish 500 Dual LNB satellite mounted on the same 30' tubular tower. I would like to combine the two antenna signals to be carried on one of the two RG6 coax cables running from the sat dish to my basement HDTV. I can use 2 diplexers to accomplish this but my question is about signal degradation. Will I notice any loss of PQ by using this arrangement. I especially don't want to mess up my OTA HDTV signal form the UHF antenna. Is there a particular diplexer that gives better performance than the rest? My Dish pic pretty much stinks already on my Mits 65" HDTV. It's fine on my smaller tvs. Anybody know a site that carries info about installations such as this? The hookup is simple enough but weatherproofing of the connections is not something with which I am familiar. Does the outside diplexer need to be mounted in a box?