My recollection of the article was it appeared some of the chokes were being
applied above their self resonant frequency, and/or the high number of turns on
the chokes contributed enough interwinding capacitance that combined with the
charger's wiring capacitance so some unintended resonance of the wiring
emerged, thus the variation in results the author saw.
I think our own Mr. Brown has discussed that unintended consequence several
times on this board. I know I look for it now by sweeping chokes I wind.
(Thank you, sir.)
It looks like this author encountered that, but did not recognize it.
But, I wasn't there. And, I know from the article I wrote for an amateur
magazine years ago that one's understanding is never complete enough. So I
applaud him for at least writing the article.
Scott
Sent via the Samsung Galaxy Note® II, an AT&T 4G LTE smartphone
<div>-------- Original message --------</div><div>From: Jim Brown
<jim@audiosystemsgroup.com> </div><div>Date:08/10/2016 3:54 PM (GMT-05:00)
</div><div>To: rfi@contesting.com </div><div>Subject: Re: [RFI] Solar Panel RFI
</div><div>
</div>Hi Ed,
It's been long enough ago since I studied it that I don't remember
details that bothered me, but dim memory is that it was some details
about the chokes used and about recommendations for specific wiring
techniques. I think I also had issues with the bonding strategy. I'll
go back and give it another read and get back to you. I also objected to
the general approach of fixing a bad system -- I strongly believe that
should be the responsibility of the system manufacturer and the
installing contractor. So I believe that what SHOULD have happened was
that the vendor's feet should have been held to the fire.
What's really good about the piece are: 1) the recognition of the
interconnected wiring as a magnetic loop, something I've been
evangelizing about for at least 10 years since I learned about it from
Neil Muncy (ex-W3WJE, SK) about 15 years ago in the context of baseband
and RF interference to audio systems. 2) the use of twisted pair for all
wiring carrying significant currents to kill the magnetic field produced
by noise (another thing I've been evangelizing about for at least 20
years); 3) the recognition that twisted pair is needed for both DC and
AC wiring in these situations because those circuits carry RF noise; 4)
use of ferrite chokes to suppress the common mode component; and 4) how
much it takes to kill RFI from a bad system.
73, Jim K9YC
What On Tue,8/9/2016 3:42 PM, Hare, Ed W1RFI wrote:
> < Not everything in it is right, but most of it is.>
>
> If there are any errors in the article, Jim, let me know what they are and we
> can see if it merits a Feedback. Or I may see it differently than you. :-)
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