You have to disconnect the ant. booster from the system. Sat. will not work thru it. Its easier to run a seperate line into the trailer. I believe you can run out of the receiver and into the trailer cable if you want to watch it in the bedroom, but I'm not positive. Must have uninterupted service from dish to receiver, splices are ok ,but no splitters .
Assuming that you have a selector switch to select between the TV antenna and an aux. input from the outside jack, it is very easy. All you need to do is to take the cable from your outside jack off of the selector switch and connect it to the satellite input for the satellite receiver. Then you need a short cable to connect from the output of the satellite receiver and from there to the selector switch where you removed the first cable. By doing that you can choose from the antenna or the input that was for cable TV and is now from your dish.