[RFI] Growing RFI problem from SolarEdge systems

[Sean Waite]

Well past 60MHz would imply interference on the VHF low band commercial
radios. The FCC tends to work harder when business and safety has
interference, if we can show RFI here it might light a fire. It'd be even
better if we could show interference in the 80-90MHz range, but I don't
know if it goes that high. Maybe someone has commercial contacts that can
file a complaint?

Sean WA1TE

On Sun, Nov 12, 2017, 18:44 Randy Standke <r55stan at gmail.com> wrote:

> The SolarEdge "optimizers" are DC to DC converters.  DC from the solar
> panels goes into them.  The DC outputs from these optimizers are wired in
> series and physically form a roof-sized loop.  The fast rise times of these
> switching circuits generate harmonics well past 60 MHz.  The "loop antenna"
> way they are wired radiates this RFI well over 2000 feet.  An April 2016
> QST
> article by K1KP addresses how to avoid the loop by twisting the wires, and
> how the addition of ferrite filters suppresses the high frequency
> harmonics.
> SolarEdge chooses to ignore this method.  Probably because it costs a
> little
> more.
>
> -----Original Message-----
> From: RFI [mailto:rfi-bounces at contesting.com] On Behalf Of Mike Kirkland
> Sent: Sunday, November 12, 2017 12:31 PM
> To: jim at audiosystemsgroup.com
> Cc: rfi at contesting.com
> Subject: Re: [RFI] Growing RFI problem from SolarEdge systems
>
> To be specific the solaredge optimizer device has to be removed from the
> back of the solar panel.
>
>
> On Nov 12, 2017 12:28 PM, "Jim Brown" <jim at audiosystemsgroup.com> wrote:
>
> > On 11/12/2017 12:07 PM, Mike Kirkland wrote:
> >
> >> Actually the FCC has proved turning the system off is ineffective at
> >> eliminating the interference and the system must be disassembled.
> >>
> >
> > Interesting -- the question is, HOW and WHAT was turned off? There are
> > (at
> > least) two components/functions of solar power systems that can
> > generate RFI. One is charge regulation, which prevents batteries from
> > being overcharged. Another is power inversion from DC to AC.  In both
> > cases, it is failure to suppress the generation and radiation of RF
> > components of pulsed currents and rectangular waves. It is quite well
> > known that excessively fast rise times, poor circuit design, and poor
> > wiring/installation techniques increase the strength of these
> > components and cause them to be radiated.
> >
> > If, for example, inverters were turned off but charge regulators were
> > still functioning, they could still be generating noise.
> >
> > Another possibility is that improper bonding by the installation
> > company might be causing noise present on the mains power system to be
> radiated.
> >
> > QST published an interesting piece a few years ago detailing the
> > heroic efforts required to suppress a really bad system.
> >
> > 73, Jim K9YC
> >
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> >
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