Normal coax routing for a RV with a single COAX inlet on the outside:
Cable runs to a switch.. If you have a wall plate with 12 volt outlet, switch, led and antenna connection the 2nd cable on the rear (Viewed from rear with 12 volt outlet at top) is USUALLY this cable.. If you wish to use it for Satellite, you will have to REMOVE it from the switch plate and extend it to the Sat Receiver,, TV out from Sat receiver goes back to this port on the switch by the way.
Better option in my opinion is to run a couple lengths of RG-6, Good quality low-loss RG-6 (not cheap stuff) one from a inlet you added and the other from the sat receiver to the cable inlet on the RV (NOTE: in many cases you will coil the cable in a compartment near the inlet and hook it in during set up).
WHY: Well, often the cable used in the RV from the factory is lowest bidder RG-59, Top quality 59 is about the same as bargain basement 6,, But average is 4 times the loss of average (Source Belden Cables). So you can imagine the difference between cheap 59 and quality 6.
And the distance from the inlet to the receiver can be much longer than you think as well. On my RV (a between 37 and 38 feet long that cable run is over 50 feet, which equals over 200 feet of RG-6 and 300 is the limit.
Which is why I ran rg-6