[mythtv-users] new video card causing interference with cable signal

Brian Wood beww at beww.org
Sun Dec 6 23:07:14 UTC 2009


On Sunday 06 December 2009 03:23:43 pm Greg Zornetzer wrote:

> FYI, I found a post on a NZ HTPC board about homebrewing a shield out of
> plastic-wrapped foil.  I tried it with aluminum foil in a plastic sandwich
> bag - no improvement.

I'm not sure how well aluminum foil would work. The best material is 
something called "Mu-Metal", if you want to shield magnetic as well as 
electrostatic fields, or copper if you are only interested in electrostatic 
fields. 

If you were to put a piece of sheet copper on the end of a wooden stick, and 
move it around in the case (perhaps covering it with plastic to avoid shorts) 
it might give you some idea of where the interference is happening, if it is 
reduced with the copper in certain positions.

The real question is: is the interference being propagated through the air, or 
through "common mode", ie: in the ground paths of the system. The waving 
copper stick might help determine this.


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