[RFI] Switchers ...

Jeff AC0C keepwalking188 at ac0c.com
Sat Nov 15 01:46:45 EST 2014

Your question is far too non-specific to have merit.  The generic answer to 
"what do you replace a noisy switer with" - is a linear supply.

It's too heavy.  It's too inefficient.  It's too big.  Well, that' gets you 
into a more nuanced question - and the answers are more nuanced.

Switching power supplies, properly designed, can be RFI quiet.  And a noisy 
PS can be quieted down for the most part but it may take serious work, 
serious money and serious time.

There are a lot of variables in the subject.  Which is part of the reason 
Jim's document is big.  If you want an easy answer, buy a linear PS for 
every switcher that gives you problems.  In the same way that a Chevette 
will let you drive from NYC to LA, it will do the job although you may not 
like the ride.


-----Original Message----- 
From: David Cole
Sent: Friday, November 14, 2014 11:53 PM
To: rfi at contesting.com
Subject: Re: [RFI] Switchers ...

The PDF must be read and understood to work correctly...
Thanks and 73's,
For equipment, and software setups and reviews see:
for MixW support see;
for Dopplergram information see:
for MM-SSTV see:

On Fri, 2014-11-14 at 21:56 -0600, Peter Laws wrote:
> On Fri, Nov 14, 2014 at 9:36 PM, Roger (K8RI) <k8ri at rogerhalstead.com> 
> wrote:
> >
> >
> > That document covers many things from noise suppression to baluns.  On
> > 11/14/2014 10:21 PM, Peter Laws wrote:
> >
> > It's a PDF and a very good one.  Just type in a relevant phrase, or word 
> > and
> > you'll be there.  Start with RFI, or switching power supplies. That's 
> > where
> > I'd start, but the whole thing is a good read, full of useful 
> > information.
> >
> > I have the ARRL handbook, Antenna handbook, periodicals.  It's so easy 
> > to
> > find things in this format all I have to do is bring up the document of
> > interest, type what I want, and read.  It's not like lugging 15 to 20 
> > pounds
> > of books and stacks of magazines, going through indexes and sorting
> > articles.
> >
> Go ahead.  Type my question into Acrobat:
> What is the best, generic solution for a wall wart or other switcher
> that is spewing trash from 500 kHz to 30000 kHz?
> OBVIOUSLY, that doesn't bring anything up.
> I have all those books and I have read about half of the PDF cited,
> but none of that answers my question.
> When someone asks "I've got one of those stupid switching supplies and
> it puts hash everywhere - what do I do?" (and for whatever reason,
> they can't replace it with a transformer), what is the answer?

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