[Elecraft] K3 noise blanker sure does the job.

[Vic K2VCO]

Brian Alsop wrote:

> Walwarts of the future will most likely be a real pain.  I understand 
> some legislation has required all of them to be switching in the near 
> future.

I have a small halogen lamp which has a walwart that can be used as a 
noise generator for adjusting the filters in my K2. It produces a 
wideband hash that is perfect for this purpose. It is very loud in most 
of the HF spectrum. I have never heard a switcher make a noise like 
this; usually they make burbles, floaters, and digital tinkles.

Speaking of switchers, I once had an IC751 with a built-in AC supply, a 
switcher which was mounted in a flat shielded box on the bottom of the 
radio. There was a tinkling noise audible on all bands which drove me 
crazy. This was some years ago, and it didn't occur to me that it might 
be the power supply. I actually sent the radio to ICOM, and they 'fixed' 
several things but the noise remained.

Although I know switchers can be quiet -- especially when you are 
careful to use baluns, etc. on antennas to reduce local noise pickup -- 
I prefer an old heavy Astron linear supply in my shack.
-- 
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
K2 no. 709
K3 no. 00007