I just purchased a new Vizio HDTV and have a question about how it works. I have called D*TV to try and get a discounted HD DVR but so far they haven't come down far enough. Anyways, I have hooked up the amplified indoor antenna and have loved the quality of the HD pic I receive from it. My question is sometimes when I watch local programming it says it is in HD, but the screen is not full up. It has bars. Other times, like when I watch Dateline on Friday night, it is full up with no bars. Today, while watching the Colts game it says 1080i Hd and it is full screen, then I switch to Fat Albert 720 HD and it has side bars. Then I turn to Hypersonic on local CW and it says 480i SD, but it is full screen w/o bars. I'm confused. I thought HD would always be full screen? Thank you in advance.