I've got three DirecTV boxes in house and my only my HD box seems to be getting interfered with. There are these reddish/greenish lines that are mostly transparent/translucent but are bugging the crap out of me. Sometimes they are horizontal across the entire picture and sometimes they are at 45 degree angles, jumping around or flashing if you will. They are not completely obstructive to the picture, but bad enough to bug me. It's been like this for a couple weeks now.

They are always there, HD or regular broadcasting. I know it's not a cable issue because they disappear when watching a DVD. I have tried different component cables with the same results and have also tried switching the DVD input with the SAT input on my receiver.

All i can think of is the HD box itself or that signal filter that they put on the coax line. I also hit the reset button and that didn't help either. Anybody have any other thoughts? I'm stumped. :(

Are the lines moving or stationary? Usually, steadily moving/rolling lines are indicative of a ground loop problem while EMI or RFI are not so prone to travel.

They are definitely moving. Weird thing is that they are angled on regular broadcasting and horizontal in HD. So should I attempt to ground the sat box somehow? I know my receiver is grounded separately with a metal screw that threads into the extrerior casing.

Rolling shaded lines or bands are a symptom of a ground loop problem. The satellite RF line or one of your pieces of A/V gear is not grounded to the same reference ground as the rest. If your satellite box is a DVR, disconnect the coaxial RF cable and put the DVR into playback. If the shaded lines go away, the problem is with the RF cable line. In that case, you should check the ground connections to the satellite receiver. Someone more familiar with the ins and outs of satellite dish setups than I am will have to help you from there.

Well, I don't have DVR on the HD receiver. However, you have inspired me to investigate the cables further. Maybe I'll utillize that service plan I pay for afterall.

UPDATE
I've localized the problem further but I still don't know how to fix it. The lines occurr with the component cables in either comp1 or comp2 of the TV and NOT when I use the old yellow video connect. It happens with both sets of my component cables so I'm ruling that out. I have a Panasonic Plasma if that matters.
I hope my sat box is going bad vs. the comp inputs on the TV. I'll pick up a HDMI cable and try that if I have time this weekend.