[PVRCNC] Laptops and 160M QRN

[Tom Lewis]

I have noticed that as well. I have a number of the bricks that plug into
the wall to charge batteries or run electronics. Some  of them are
terrible. I have a small 12 volt 1 Amp charger for the boat battery and it
can not be plugged in while I am on the radio.

Tom
N4TL




> [Original Message]
> From: Brian Alsop <alsopb at nc.rr.com>
> To: PVRCNC <pvrcnc at mailman.qth.net>
> Date: 9/21/2007 10:46:33 AM
> Subject: [PVRCNC] Laptops and 160M QRN
>
> Guys,
>
> For what it is worth, laptop AC power adapters (switching supplies) can 
> generate huge
> amounts of noise on 160M.  Found this out after replacing one of the 
> desktop computers here with a laptop. 
> Doesn't seem to impact 80M and higher freqs.  Using an AM BC band 
> transistor radio, it appears that the AC line and DC output line are 
> both highly polluted with RF-- as is the supply area itself.
>
> The noise appears in about 20 KHz wide bands separated by bands or no 
> noise bands.
>
> Tried ferrites on the input/and output lines to quiet one down.  No 
> luck. Ferrites are pretty useless for 160M anyhow.
> Solution is something like an ASTRON 5A analog supply.
>
> I understand all the power plugs in the future will be non-transformer, 
> switching type supplies.
> How these have been kept exempt from RFI specs is beyond me.  $$ I guess.
>
> XYL's laptop (an IBM) less of a bad actor.
>
> 73 de Brian/K3KO
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