Although it has 'satellite' in the URL/name, they cover just about everything tuner-related as far as cable/sat/OTA reception is concerned. Some very astute folks over there who have good technical information to share on hardware, etc. Here's the URL-
I recently upgraded to a Vizio LCD TV and have visible VITS lines on the top of the screen while watching broadcast TV. It's predominately on one channel but I don't see it at all times on that channel and it's visible on other channels occasionally. Vizio is telling me the TV is fine and it's the TV station or my antenna. This particular TV doesn't have any user adjustment of the picture position while watching broadcast TV. I'm guessing the TV is overscanning and / or it's not centered correctly but since it's primarily but not always one channel it's hard for me to argue with Vizio. I have no idea how it could be my antenna.
Does this sound like the TV or the stations? Is there a spec on where the VITS lines are broadcast such that they should never be seen on the TV screen?