Video Hum Bars

You need a ground break where the coax attaches to your TV. You can get them a Rat Shack for a few dollars.

The device (Ground Isolation Transformer) is a band-aid and should be treated as such. If you can use the device with no side effects - great... If you have long cable runs, or connections to multiple devices - keep in mind the shielding on all of the cable past the device is floating and thus an antenna. Problems are usually worse in urban / suburban settings.. Best choice is to figure out whats wrong with your cabling / grounding - may not be the easiest route, but the side effects fixing the problem are usually blacker AV presentation.

Thank Rwwear and J k I will follow both of your advise. I will spend a couple of bucks and see what the Shack as to offer..and I will check my cable runs....I do live in the 'burbs.

The reason this happens is that you have too many paths to ground usually. It doesn't always cause problems but it sometimes does. In most cases, and I've seen many, breaking the ground on the TV cable input fixes the problem with no side effects.