[RFI] DC Power supplies

Jim Brown jim at audiosystemsgroup.com
Mon May 9 01:10:15 EDT 2016

On Sun,5/8/2016 1:04 AM, Roger (K8RI) wrote:
> That quiet power supply is a Tenma 40A with adjustable voltage.  It 
> was sold by the same company that sells Rigol. I have A Rigol spectrum 
> analyzer. 

Hmmm -- the power supply in my Rigol puts out enough RF noise that I can 
see it on an inductive probe. Rather disappointing if you're trying to 
use it to evaluate noise in a product. When I discussed this with the 
distributor at Dayton a few years ago I got a blank stare.

As to these supplies being "clean" -- how close are they to RX antennas? 
I have a no-name supply that hams told me was clean, and it's a holy 
terror on the 160M vertical that's 25 ft from the shack. Not so bad on 
high dipoles, but the SteppIR 200 ft from the shack zeroes in on it on 
some HF bands. And I've got it heavily choked and caps across in and out 

73, Jim K9YC

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