[600MRG] 630M Noise Reduction

[david vanhorn]

Agreed.  Any testing engineer can tell you horror stories.

On Wed, Jan 23, 2019, 1:28 PM Michael Mussler <mmussler at centurylink.net
wrote:

> I read an interesting article once about wall wart power supplies. I think
> it was published by Electronic Design News. The author obtained a half
> dozen wall warts, all manufactured off-shore in Asian countries. They
> removed the plastic enclosures (with difficulty) and discovered a number of
> interesting things:
>
> PC Boards that had silk screened outlines of missing components relating
> to EMI suppression
>
> Guts with PC board identifying information that didn’t match the
> information on the outside enclosure (power and current ratings)
>
> Guts that had been removed from some other piece of equipment and
> re-packaged
>
> Tests that indicated the FCC and CE marks on the enclosure were false
>
> The sad state of affairs regarding compliance with FCC regulations in the
> US is caused by a shortage of funding and staff with technical backgrounds
> to police compliance to the rules. It has become a "complaint driven”
> system and like so many other government services, the squeaky wheel with
> big bucks and political clout gets the oil. There have been some published
> situations where more drastic consequences of FCC non-compliance have been
> identified (interference on aircraft caused by personal electronics) but
> these events are the exception. In reality, the EMI situation in our modern
> lives is akin to air, water, visible light and noise pollution. It is made
> worse because it is not something the general public can experience
> directly with their senses.
>
> The control of EMI in modern electronics is not rocket science. I’ve used
> switching mode power supplies salvaged from obsolete early generation PCs
> that were so “quiet” they could be used to power my HF radios with no
> interference issues whatsoever. It all comes down to proper designs with
> EMI suppression features that add cost without directly impacting
> efficiency and regulation of the supply.
>
> Good luck, and don’t give up! Be sure to pass document your experiences
> and pass them along to the ARRL. They actually have people on their staff
> who are trying to work this problem.
>
> 73
> Mike Mussler, AI8Z
> ex WD2XSH/12
>
>
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