[PVRCNC] Laptops and 160M QRN

[Brian Alsop]

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