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[RFI] Filtered connectors for video noise

To: <rfi@contesting.com>
Subject: [RFI] Filtered connectors for video noise
From: ka5s@earthlink.net (Cortland Richmond)
Date: Sat, 27 Oct 2001 02:35:56 +0800
Here is another suggestion.  If changing the monitor's contrast control while 
it's running affects the  interference, then it is coming from the monitor. If 
not, then it is coming from the card, OR the video cable.

I once troubleshot a horrible video problem with my brother's professional CAD 
station. He worked from home. Despite a shielded monitor with over a hundred 
screws in the shielded box, it was knocking out TV reception in the apartments 
next to his on all six sides.  I tracked it down to improper shield 
terminations in the video cable. We were able to add another shield over the 
video cable, properly terminated, that solved the probem.

I saw a similar problem with a cable shipped by a company selling TV cards for 
computers. Their card connected the TV video in a "T" fashion, and since they 
had put pigtails over an inch long on all the shields, those shields radiated 
video signals when we evaluated the card with our computer, with the TV card 
not selected.  Now the interesting part: The TV card _had an  FCC ID_. It had 
apparently been tested ONLY in operational mode. Adding a poor quality video 
cable made the system in which it was installed radiate, and at non-compliant 
levels.

Cortland
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