Re: [HCDX]: RE: PC based QRN
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Re: [HCDX]: RE: PC based QRN



One of the biggest problems with laptops are the power supplies and seems no
matter what you do, short of unplugging them, the noise is really nasty.
The Laptops themselves are pretty good but the battery chargers are really
very poor.  Even with r-f clamps and all kinds of stuff, still produces a
really nasty noise.
Bob Montgomery
-----Original Message-----
From: jerry.monroe@xxxxxxxxxxxxxxxxxxxxx
<jerry.monroe@xxxxxxxxxxxxxxxxxxxxx>
To: hard-core-dx@xxxxxxxxxxxxx <hard-core-dx@xxxxxxxxxxxxx>
Date: Monday, December 28, 1998 10:13 PM
Subject: [HCDX]: RE: PC based QRN


>re:
>
>the thread on computer generated noise,
>
>I agree that a well shielded receiver coupled to a well grounded, somewhat
>removed coax fed antenna is the ticket.
>
>I would imagine that some of the newer sets that are not well shielded will
>pick up the clock frequency of the nearby PC , anyways.
>
>Some success can be had by wrapping the power leads and peripheral cables
>on torroids thus "choking" the RF at the source.
>There are also ferrite's out there for clamping on to ribbon cables.
>
>As one who has had to make low frequency communications equipment
>compatible with both  US and European  regulations (aka CENELEC) getting
>rid of microprocessor based noise is no easy task !!
>
>On other misc. QRN noises, I found a interesting pulsed noise which
>originates on from my VCR when it is the off/standby mode only, it shows up
>870-900 khz only, pretty much wiping out the GE SuperRadio performance in
>my home on those frequencies.
>Many devices that operate with a switched mode power supply never actually
>turn off completely, hence the only way to stop it the QRN is to unplug it
>..
>
>73s Jerry
>
>
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This is a message from "Robert Montgomery" <RMonty3@xxxxxxxxxxxxxxxx>
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For more information, please check http://www.iki.fi/rko/hard-core-dx/
or email Risto Kotalampi, risto@xxxxxxxxxxxxxx
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