I bought a TIVO to get OTA local channels through my receiver. The living room was wired so that the subwoofer in another corner from the receiver is wired using coax in-wall with adapter heads to plug in. Since where the subwoofer is located is also the best location for an antenna, I thought of putting a switch on both ends of the in-wall cabling to switch from the sub to the antenna when watching local HD football over the air. However, I'm having reception/signal quality issues. Is it coming from using two switches, multiple cables, etc? Length? What is most likely causing problems?