CATV Groundloop, toBeat a Dead Horse and the Shack

I just noticed a very affordable new (to me) coaxial isolation transformer device in the MCM Electronics preferred customer catalog. This one has type-F male at one end & female at the other. Stock #33-6925 list $17.19, presently selling for $12.95.
www.mcmelectronics.com

Keis,

I have DirectTV and still got hum from the cable (from the sat dish) connected to my system. A simple wire grounding the sheath (outside connector)of the cable works perfectly.

I bought a Modial Magic unit and it didn't work. Still have hum but only when the cable connection is attached to the stereo/video system. Friend who is an electric engineer couldn't get ride of it so ended up going to DirectTV. Problem went away. AT&T broadband is the culpret.

Thanks all. Plenty of useful ideas.

If you decide not to try the DIY approach, and want to pursue my earlier suggestion about the Mondial "MAGIC" unit, you can buy this unit from Audio Advisor. They also sell a nearly identical unit made by Tributaries, which is also priced at $99.

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.

I just ran a wire from the outside of the catv coax connector(with an alligator clip) to the ground on my power supply (or back to the ground on your AC socket) where everything is plugged in. You can buy (from Radio Snack) a "catv grounding block" which connects two catv cables and has a screw where you can attach this wire to ground.

Take a run back to the Shack, dump the interuptor you bought, pick up these: Parts #15-1140 and #15-1253, tie them back to back via 300 ohm leads, insert in your cable before any equipment and voila, loop broken. Not very pretty but effective, (save slight signal loss; cheap enuf to experiment with tho.)

OR......surf on over to here:

http://www.hometech.com/video/atten.html#dc

and scroll down to "63400 Groundbreaker." Neater package.

This is pretty simple if you can fabricate connectors (or you know someone who can). Just cut off the type F on your incoming coax & install an RCA there instead. Then make an adapter cable with RCA at the isolator's output & type F (or whatever is required) at the opposite end connecting to your cable box, TV, VCR, whatever component it leads into. Alternatively you can buy some little adapter gizmo's to convert RCA to type F's, but this would cause some loss of signal level (may not be an issue with Cable, usually their levels run quite hot) & possible even some VSWR degradation? It all depends upon how demanding your system is? If it's HDTV quality then by all means don't skimp. It it's just a $399 Toshiba TV, then I wouldn't worry about it at all.

I think the Mondial "MAGIC" ground isolator has "F" connectors at both ends so it can be inserted into the cable line.