With Dish/DirecTV the diplexer can go just about anywhere but put it close enough to your cable runs. I ran a DTV setup, was a unique situation but was a easy solution to the cable issues they were having. The more rooms the more signal loss but the average quad diplexer should be fine but a commercial diplexer will also work for up to 12-16 ports, as I said more runs more signal loss is great for apartments or hotels.
JNS Contracting Plc "We do it right so you wont have to"
