[RFI] Computer Hash

Cortland Richmond ka5s at earthlink.net
Sun Feb 25 19:31:16 EST 2007

Good evening, Billy.

More information is almost always better than less.   Does the interference
start when you connect the audio between a computer and the radio set?  If
so, it may be curable by adding RF filtering along the audio path.  Does it
go away if you turn off a desktop CRT-type monitor? You may be able to
replace the CRT with an LCD.  Does it go away if you unplug the laptop
mains supply and operate off the internal battery?  You may be able to
filter the existing supply, or use another, quieter one.  Is it present all
thr time no natter what is connected? In that case, how near is your aerial
to the mains or telephone wiring, or to your computer?   Moving it away may
help.  Is your aerial a single wire or coax fed?   Changing to a
well-choked coax or to a balanced feed may help. 

Cortland Richmond

> [Original Message]
> From: William Conlan <w_conlan at eircom.net>
> To: <RFI at contesting.com>
> Date: 2/25/2007 5:33:25 PM
> Subject: [RFI] Computer Hash
> Hi Guys, anyone have a fix for stopping computer noise blocking out HF
>  I use 3.5" Jack lead into PC microphone  & 3.5" Jack into radio speaker
source on radio.
> As soon as I switch on computer all I get is noise.
> This is not a problem on VHF only HF 2Mgh-30Mgh.
> Also happens on laptop, which I though would be less noisy.
> Bought a couple of RF Mains Filters from UK, but still no joy.
> Many thanks in advance.
> A great and interesting site to say the least.
> Regards.
> Billy.
> S.Ireland.
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