Marcus,
For HDTV signals - what sort of antenna are you using? You probably want to get a special antenna (not just any rabbit ears) and place it appropriately. HDTV signals require a stronger signal than regular old TV. A lot of times people go to the extra efforts to mount a special antenna (Like many Terk models) that cost $50 or so. This requires extra wiring from your TV to your roof though.
Andrew

