Another inverter brand I found to be absolutely quiet is Fronius (also German
made). That is the brand of inverter I have for the solar power system I have
at my house. Just after I had it installed, I checked every band with a SDR
(connected to my station antennas) to see if any signals stopped when I shut it
off. I found nothing. I know all inverters use switching to do their thing
and was curious what frequency my Fronius uses. Standing near it in the garage
with the SDR heard nothing. Finally, I draped a wire as the SDR antenna over
the inverter and found very weak signals at 20 kHz intervals. Compare that to
SolarEdge systems that a portable radio picks up at 700 feet.
Randy KQ6RS
-----Original Message-----
From: RFI <rfi-bounces+r55stan=gmail.com@contesting.com> On Behalf Of Kim Elmore
Sent: Wednesday, February 5, 2020 7:58 AM
To: Tony <dxdx@optonline.net>
Cc: Hare, Ed W1RFI <w1rfi@arrl.org>; Rfi List <rfi@contesting.com>
Subject: Re: [RFI] SolarEdge RFI Inverter On/Off Test
All of this has been VERY informative. My wife suggested we look into a
photovoltaic system for our house, and I find the idea very compelling. But I
won’t do it at the cost of my Amateur Radio activities. I may talk to some
locals, but any system will have to not merely RF quiet, but absolutely RF
*silent* from DC to as high as I can collect the equipment to measure.
Kim N5OP
"People that make music together cannot be enemies, at least as long as the
music lasts." -- Paul Hindemith
> On Feb 5, 2020, at 1:59 AM, Tony <dxdx@optonline.net> wrote:
>
> All:
>
> My neighbor gave me permission to shut off his SolarEdge solar panel inverter
> while I ran some tests. I recorded the results at my home station and noticed
> that the S-9 spikes disappeared when the inverter was turned off. The noise
> floor also dropped considerably.
>
> A few remaining spikes were tracked to the cabling that feeds the solar panel
> optimizers which were still running in safe mode. Unfortunately, there's no
> way to shut off the optimizers without physically disconnecting them.
>
> The noise reappeared when the inverter was turned back on.
>
> Before I left, I decided to probe the AC lines running off the house main
> panel for RFI. Sure enough, there were high levels of the same noise on the
> the exposed lines that run along the basement ceiling of my neighbors home.
> All that noise is feeding into the AC lines so the house wiring makes for one
> big antenna.
>
> Less significant, but worth mentioning is that the inverter does not have a
> dedicated ground rod. It's grounded instead to a water pipe in the basement
> which then splits to the main panel with a 6 foot ground wire.
>
> I also noted the model number of the inverter and found that it's the same
> 6KW unit that Tony Brock-Fisher found to be very noisy.
>
> More to come.
>
> Tony -K2MO
>
>
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