I have a tv hookup in BR. If I connect a cable to it and put up antenna, I get "over the air" reception. If the campground has cable at the post with water/electric and I connect a cable from my fiver...
I have separate connections, for OTA, and for cable, plus a sat connection, for my bedroom tv.
You may need to move your coax to a second connection, to work with your outside cable tv hookup. You have to set tv to cable and rescan also. This is how mine is setup.