For the most part, we don't watch too much, if any, TV while camping. We do have a small (15" maybe 17") flat screen TV that has been used on occasion. I've used it at parks that have cable hookups (not our usual stops). There must be a splitter that connects the input from both the roof top antenna and the coax plug on the "service" side of the camper, since when connected from the camper to the park's PEG then to the TV via the coax plug inside the camper, channels are available. I've never used the roof top antenna but have used the "magic/miracle" HD antennas (As Seen On TV)! If camping relatively near a metro areas, I've gotten decent reception with it. I've not tried this setup in remote locales tho, so YMMV.
If you're not livin' on the edge, you're takin' up too much space!
2007 Shadow Cruiser x210, 2004 RAM 2500 4x4 QuadCab SLT 5.9L CTD, Factory Tow Pkg (3.73 axle), HaulMaster WDH