MIT makes a coaxle ground loop cable. I use it and not only does it work well but it also gives me a little better picture. It was pricy though at a hundred bucks.
CATV Groundloop, toBeat a Dead Horse and the Shack
Sorry, I know this one has been discussed at great length (over and over) but I went down to pick up one of those Radio Shack ground loop interuptors only to discover that it's RCA only. Personally, having spent too much time and money on the interconnects within the system, I'd hate to now throw in Shack technology between components. Ideally, I'd like to put the interruptor on the coaxial line coming in, before it even hit the first component. Do we have the technology for such a feat? (Ok, I'm sure we do, but what's the best way to go about it)? Many thanks.