As a matter of fact, the house does have 300-ohm twin lead wire going to each room and is connected to an old antenna in the attic. However, the wire is in pretty bad shape with the insulation cracking and peeling all over the place. I've been removing the connectors in each room and reusing the boxes for Ethernet.
I may as well run a couple RG6 drops to the family room, one in each bedroom and MAYBE two in the master bedroom. I'll just follow the same paths I used for the CAT6 and have it all end at the CAT6 patch panel. I'll leave everything unterminated for now and buy keystone jacks for it later on.
As a matter of fact, the house does have 300-ohm twin lead wire going to each room and is connected to an old antenna in the attic.
That's funny because I discovered an antenna preserved in perfect condition in the crawl space attic above my single level home. I saw some twin lead 300 ohm in the basement and I traced it up to the attic.