If your's is like mine, there is a jumper cable (inside your RV) that connects the exterior cable or satellite in connection on the outside of your RV to the antenna amplifier inside your RV. The key to getting a satellite signal is to disconnect that short jumper, and to connect the antenna cable from your satellite box to the connection you removed the jumper from. This makes a direct connection from the exterior fitting to your satellite box, and bypasses the amplifier which may mess up satellite signals.
If nothing works, for at least testing purposes you could connect the cable from your dish directly to the satellite box, and thus bypass your RV wiring completely. At least then you know everything is set up correctly - except for your RV wiring, of course
There's lots of advice and information in forums... sometimes it is correct. For example, all of my posts are made by a political appointee who got the job as a reward for contributions to my diesel bill.
2011 Jayco 28.5RLS; 2008 Chevy Duramax; Pullrite Superglide Hitch