J, I don't know what model receiver you have and what you mean about 'splitter in the house'.
However, if you run the feed directly to the camper receiver and it worked, the house isn't the issue.
The problem is a probably a splitter in the camper, designed for campground CATV inputs which can feed mulitiple TVs in the camper.
There is an antenna booster somewhere in your camper; it provides power to the antenna amp and switches the output from antenna to CATV (from the outside connection)... if "on" the green light lights and you are on antenna, "off" and you are on CATV. This won't work for satellite feeds.
Some campers have a CATV feed and a satellite feed, I assume your's does not.
You will need to remove the booster outlet off the wall or ceiling and remove the cable that runs in from the outside connection and connect that COAX directly to the receiver. See the picture. I did this and used a barrel connector and drilled the plate and made it permanent. That way you can screw the outlet back down.
There is +12vdc and ground on the booster, so be careful to not blow a fuse.
The manual (link) might not be for your antenna, but the booster is the same. (or should be)