Ground loop or ?

Rich Carrillo

May 24, 2000
Haven't posted here in a loooong time. Anyway, I've been trying to help my brother in law start an LCD HDTV setup with some limited success. He wanted to mount the TV on the wall and run the wires through the wall to the components about 15 feet away. The TV connects to the HD DVR via a regular old coax cable, which probably explains why it doesn't look like a true HD signal, but at least it's working for the time being until we can find a long enough HDMI or component cable.

The real problem occurs when we try to connect the Xbox 360 via a long 10 foot monster component cable and an extra 5 or 6 foot RGB cable from Fry's. That's when the interference shows up in the form of horizontal, swimming bars. It's horrifying. I've been reading up on old posts about ground loops and interference, but I am a moron at electrical and honestly, while I think a ground loop must be the problem, I can't really tell for 100% sure because the picture from the coax antenna cable works fine for the HD DVR (albeit non HD) and the DVR and the 360 are plugged into the same outlet. I also tried switching the 360 and DVR plugs still using the same outlet and it doesn't make a difference, which leads me to think it's a cable issueand not a power issue. Before I tell him we should go and look for a really long and expensive single cable which might not solve the problem, is anyone familiar with this and if it is definitively ground loop? Any suggestions?

Bob McElfresh

Senior HTF Member
May 22, 1999
First: connect the xbox directly to the TV without the extra RGB cable. Does the interference go away?

I'm guessing this is interference being picked up. While the Monster cable is fine, is the RGB cable from frys thick like a shielded cable or does it look like walkman-heaphone wires?

The other issue is 'ringing'. This happens when you send HD video down a wire and it hits barrel connectors or audio wires that are not the proper 75 ohm impedence. The signals hit these connections like a speed-bump and ... well you may be seeing the results.

To connect the HD cable box, buy a cable from The owner is a member here and has many happy customers. Mention HTF and he will take care of you.

Hope this helps and let us know what happens.

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