A:Answer What is connected to the other end of the co-axial cable? If it's an antenna, then you need to re-run TV setup and scan for channels. Depending on where you are, what kind of antenna you have, and where it is positioned, the number of over-the-air TV channels you can receive will vary.
In my case, I have a Mohu indoor antenna ( https://www.bestbuy.com/site/mohu-leaf-30-indoor-hdtv-antenna-black-white/3488024.p?skuId=3488024 ) positioned in a window, high up, and I get 30 channels with good quality. Depending on where you are, you may need an outdoor antenna, possibly even one which can be moved to point at transmitters.
Hop this helps.