noise interference

[hecktic]

how do you know if you have this on your HDTV?

[Bobsama]

Typically EMI is less prevalent with LCD's and Plasma TV's; it was a larger issue with (unshielded) CRT's and rear-projection TVs. Easiest way to check would be if you have a fuzzy picture when running at maximum resolution: play something 1080p if it's a 1080p panel, otherwise run 720p. Images should look crisp. You'll get interference and poor picture quality if you decide to use composite video. You're likely to get it with S-Video, as well. Component video and digital standards (like HDMI or DVI) are much less likely to poor quality from the cable. Obviously, use the highest quality connection possible.

If you're just using the normal coax for TV signal, try moving the cable if you do have a blurry picture. Mind you, that won't help on over-the-air broadcasts and normal video is 480px tall, so will be noticeably blurry on HDTVs. Otherwise, avoid running power cables (both to a wall/power strip and to, for example, speakers) with signal cables. Grouping signal cables together is generally alright as you're usually only using 1 of those cables and they're not high-power.

[STEvil]

only an issue with analog signals basically. if you have an issue with a digital connection its a bad provider/cable/end/crap tuner 99% of the time.

Also capacitors go bad in TV's sometimes and can cause a similar issue.

[hecktic]

yeah the cable signal might be bad.... the TV seems clean... its 3D LED HDTV