If the trailer was prewired for antenna and satellite I would assume there would be a selection box to switch between them.
When I put satellite into my older trailer I had to install an A/B box to separate the different signal sources. Are you sure you don't have a selection box that allows you to switch or does the amp cover have 2 connection ports on the front of it. This is sometime how they separate campground cable from antenna.
WBCCI 12156 AIR 3144 WACHUNG TAC NJ6
2004 Excursion 4x4
1991 34 ft. Excella +220,000 miles, new laminated flooring, new upholstery, new 3200 lbs axles