[Elecraft] Computer Noise ruining 20 & 30m

[John Klewer]

Prior to buying my (ultra-quiet) Mac G5, I experienced a significant 
amount of noise from my PC....doing a search with a handheld shortwave 
radio in AM mode revealed it was primarily emanating from  the AC power 
cable area.

Clip-on ferrite chokes on the power cable were completely ineffective.

I dismantled the computer, opened up the power supply and replaced the 
power supply input connector (unfiltered) with a filtered one purchased 
from Digi-key and the problem went away! Sorry, but I do not have the 
part number...they are available from Digi-key, Mouser, Newark, etc, etc.

In the interest of maximizing profits the manufacturer omitted a 
filtered input connector and let me instead buy it aftermarket.

John, N6AX






Alan D. Wilcox wrote:

> Hello,
> I gave away the feeble old PC I had by my radio equipment and replaced 
> it with a newer one ...
>
> Now I have S9+ noise wiping out 20 and 30 meters.
>
> Using same keyboard, mouse, monitor; just the PC in a new case. 
> Evidently it has a
> noisy switcher supply in it. Tried 110V in-line filter, also different 
> 110V house circuit,
> but still have noise. Grounds don't help. Don't happen to have a box 
> of toroids for chokes.
>
> I've got an old PC supply or two in the junk box, but hoping something 
> else might fix.
>
> Any thoughts on an easy fix?
>
> Thanks,
> Alan
>
> Alan D. Wilcox, W3DVX
> 570-321-1516
> http://WilcoxEngineering.com
> Williamsport, PA 17701
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