I have a brand new Tivo Series 3. Comcast is coming tomorrow to install the cablecards. Meanwhile, the cable line is running directly to Antenna In, and the Tivo itself is connected via HDMI to an HDMI switching receiver. I've done some googling, and I understand that HDMI doesn't work with standard def 480i as it needs 720p. Is that the problem? I'm really hoping to have this set up optimally before Comcast gets here, as I want to make it as idiot-proof as possible, so if this sounds like a bigger problem, please clue me in! Thanks ...