I have a Dish Tailgater setup that works really well. To make it work, your wiring has to be direct from the dish to the reciever. The other self-aiming type of dishes require the same thing. They need two way communications and to send 12v power back down the cable to power the dish mechanism. So when I say nothing between the dish and the box, I mean absolutely nothing - especially those antenna booster boxes almost all RV's have.
Normally, the junctions, splitters and switches inside the walls of your RV prevent this from working. So it is a bit of work to either eliminate some of these things, or drill a hole and run a new cable from outside to inside.