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Re: [RFI] Topband: Computer RFI on 160

To: topband@contesting.com, rfi@contesting.com, Bill Tippett <btippett@alum.mit.edu>
Subject: Re: [RFI] Topband: Computer RFI on 160
From: Michael Brown <k9mi@yahoo.com>
Date: Wed, 29 Oct 2008 13:23:57 -0700 (PDT)
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
For a noisy pc power supply fix, Antec has never let me down.

73 - Mike K9MI


--- On Wed, 10/29/08, Bill Tippett <btippett@alum.mit.edu> wrote:

> From: Bill Tippett <btippett@alum.mit.edu>
> Subject: Topband: Computer RFI on 160
> To: topband@contesting.com, rfi@contesting.com
> Date: Wednesday, October 29, 2008, 3:40 PM
> In 2004 I had a problem with a neighbor's PC birdie
> drifting onto the
> Chesterfield Island (TX9) expedition frequency. 
> Fortunately it was a
> new "white box" computer assembled by a local
> company and I was able
> to return it and have the power supply exchanged for free. 
> Problem
> solved...I thought.
> 
> Recently I began hearing another birdie on 1822.  Using my
> Beverages
> and my trusty Sony ICF-2010 receiver, I was able to trace
> the birdie
> to the same neighbor.  The Sony unit is especially nice
> since you can
> tune it to the exact frequency of any birdies, and the
> internal whip
> antenna is quite directional using the internal S-meter
> once you get
> close to the source.  Fortunately I don't have many
> neighbors so it
> was fairly easy to locate.
> 
> They still had the same computer but apparently it had
> developed the
> same problem over the years.  On-site I tried about 8 turns
> of the
> power cord through a Mix 31 2.4" toroid, but that
> didn't dent the
> noise enough.  Fortunately these neighbors are good friends
> so they
> suggested I take their computer and fix it.  When I got
> home and
> opened the power supply, I saw there was zero filtering on
> the modular
> plug. Fortunately I had purchased several CORCOM 6EF1 EFI
> line filters
> several years ago for ~$5 each.  A few minutes with a screw
> driver and
> soldering iron and I had the standard modular plug replaced
> with the
> CORCOM.  Problem solved forever!  (I hope).
> 
> Although the 6EF1 lists for ~$15 each from normal
> distributors, I see
> someone on eBay is selling them for $75/10 units.  I've
> seen them for
> sale at lower quantities and prices so you might watch for
> some to
> appear.  Having a few of these in your junk box for
> emergency RFI
> fixes might be a good idea.
> 
> 73,  Bill  W4ZV
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