Murry52, can you state what kind of satellite service you have, single, dual, or triple lnb, how long the cable is you are running from the dish to the trailer, and is it RG6 cable (even running from the receiver to the inside coax plug)?
In my experience with Directv, a lot times it is a bad coax connection in the line somewhere, or wrong/too long cable length (ie using RG59) ....all of which don't allow the receiver to switch between the even and odd transponders...which require 18V and 13V.
It can also very likely be the splitter that Road-King is referring too, depending on how it is wired or if it has loose/bad connections. Have you tried just wiring it direct from the dish to the receiver (bypassing the coax outlet) like running the coax thru a window.
Once we troubleshoot all the above, we can also see if the lnb itself is bad.
I'm confident with all the electrical gurus we have here, your problem is going to get solved asap.
2011 Flagstaff 831 RLBSS
I've just ordered a chicken and an egg from Amazon.... I will keep you posted.