[RFI] Switching Power Supply test Video

[Michael Coslo]

The antenna is a 96 foot doublet roughly 55 feet above the radio, and directly above it. Fed with ladder line.

One of the most important aspects of this is that I make no assertion that there is no hash. I show it in fact. and at frequencies that it happens at.   At the end of the video I note that this is not a rigid test, but something a typical Amateur might experience.

The interference I chose to show that was visible is below the AM Broadcast band. And it is there. The noise floor on the BCB  was too high to get anything of use there. But if you were working the experimental bands there, you wouldn’t want to use a switcher. For a clean source, I’d suggest batteries.

Unfortunately, it is not always possible to get meaningful results with meaningful defined as tightly controlled laboratory conditions. I would love to see the work that has the lab results.  Anyone have the cites or could grant access to their own work in this area? It would be especially helpful to see the tests done on the Alinco in question, but I’m willing to be educated by seeing the meaningful tests on any Switch mode power supply.

-73 de Mike N3LI -

> On Aug 7, 2016, at 1:30 PM, Paul Christensen <pchristensen at ieee.org> wrote:
> 
>> "1) there's no information about antennas in use, or how close they were to
> the shack. 
> 
> And that's probably the most influential factor.  The proximity of the SMPS
> to antennas, lines, and equipment mean everything.  We often hear/see
> reports that "brand X" supply is quiet and produces no hash.   That
> statement may only be true in that one installation.  We all have different
> installations that can have a profound effect on the degree of SMPS
> interference.   
> Meaningful results require thorough EMC testing, using regulatory and
> industry-standard testing methodology.
> 
> Paul, W9AC 
> 
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