Hmmm....
OK, it's not possible to never power-off the receiver in an rv that goes anywhere.
I think you might be on the fringe of "no signal." This may mean that you need to select eastern or western arc appropriately or get out from under the trees that are blocking your signal. When you're on the fringe you might get sound and picture anomalies.
The way I do it is I have a switched power strip and before I roll out I turn it off. At a new campsite, hook up everything and then switch it on. This seems to make for less fooling around.
You do indeed need to go through the scan/check switch procedure at each campsite but hooking up and then switching on automates this.
-jbh-