We've owned a Dish Playmaker (surprisingly the best prices sometimes is at camper world) now for 3 years. I've had a lot of experience with the unit.
First of all, do not put it on your roof unless you always point your trailer North when you camp. The units have a handle that needs to point North. That is step one.
Secondly, the satellite includes 50 feet of coax. I've used all fifty feet sometimes trying to get out from under the trees or to find a hole in the trees to see the sky. That makes finding the satellites easier.
The Apple store (and Android) has a free app called SatFinder Lite. You hold it up to the sky and it shows the satellites. There are 3 satellites you need, 110,119 and 129. If you buy the duel dish (can be used with 2 receivers) you also can use 65. (read my thread about this elsewhere). If you buy SatFinder, it has some really nice features that make it a breeze to use (isolates only the satellites you are looking for).
Pro tip: Buy the black carry bag for the dish itself. It will also fit the tripod stand. Also, buy the stand! Most times the dish will work well on the level ground, but not as well as being elevated 3 feet (and not because it is closer to the satellites!
). Has something to do with ground effects.
The stand is a PITA to pull out the legs. I just throw the legs extended in the back of the truck bed extended and ready to go.
Thirdly, use the SAT connector on the side of the Airstream to make the connection. Plug the SAT cable inside into the Wally. When setting the receiver up initially, CALL DISH! You cannot do this yourself. They have to activate your account. If you have Dish at home, it only costs $7.00/month for Wally's service. That is a great deal. During your initial setup, run the cable from the Dish through the door on your Airstream and to the receiver. Dish will ask if it is connected directly. Just do as they say, you can change this later once it is working. Sometimes the initial setup will not run and they will blame the connection outside.
You can get local channels wherever you go. If you have Dish at home, you cannot get the locals by using the Dish app. They say you can, but it does not work. A quick call to Dish, give them a zip code and you're done. Dish has very good service and will stay on the line for as long as it takes to correct a problem.
I've said enough.