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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