If the antenna on your roof is older than 40 years then it probably uses flat wire that you haven’t seen anywhere else. This 300-ohm “twin-lead” cable was all the rage in the 1950s as it was inexpensive to make and easy to install. However, it was replaced eventually by the kind of coaxial cable you see all over the place.
To be honest, the flat wire is a really good fit for an antenna since its impedance characteristics (an important measure of how well signals “flow” through a wire” is fairly similar to that of the antenna itself. In order to use coaxial cable, an antenna uses a piece of equipment called a “balun” which converts the antenna’s 300-ohm impedance to the 75-ohm impedance of a coaxial cable. Baluns also used to be quite expensive, which was another reason people didn’t use coaxial cable. Today they’re ridiculously cheap.
Although twin-lead wire is pretty good for antenna signals, it’s completely unshielded and prone to interference from cell phones which obviously people in the 1950s didn’t have to worry about. Today though… you do need to worry about it and you also probably need to worry about the sun damage that 40-60 years of direct exposure has done to your old flat wires.
Normally I say, if it isn’t broke… don’t fix it. But if you’re seeing any sort of interference on your TV picture while watching antenna TV, I would rewire the line with coaxial cable and get a balun to connect your old antenna to it. This will give you much better results, including stronger signal and the ability to split the signal easily to go to multiple TVs. You may even be able to repurpose some cable company leftover wire for this purpose.
Folks, some things made in the 1950s are classics. Old cars, old music, those are great. Old wires though… time to deal with them.