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Re: Topband: Progress with ugly computer noise

To: topband@contesting.com
Subject: Re: Topband: Progress with ugly computer noise
From: Jim Brown <jim@audiosystemsgroup.com>
Reply-to: jim@audiosystemsgroup.com
Date: Wed, 04 Jul 2012 09:14:09 -0700
List-post: <topband@contesting.com">mailto:topband@contesting.com>
On 7/4/2012 6:10 AM, Bill Cromwell wrote:
> Next I'll be getting my hands on some ferrite core materials and looking to 
> see just how far I can reduce the noise.

When faced with a noisy computer, the first thing I'd try (other than 
replacing the noisy supply) would be a multi-turn choke on the power 
cable, optimized (number of turns and core) for the band(s) where you're 
hearing the most noise. If noise remained, I'd next tackle the video 
cable and the printer cable.  Use the graphs in Appendix One of 
http://audiosystemsgroup.com/RFI-Ham.pdf as a guide to picking the cores 
and winding the chokes.

Do your fellow hams another favor -- post the brand names and/or vendors 
of both the noisy power supply and the one that fixed your problem (if 
it does). :)

73, Jim K9YC
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