Be careful what we wish for.....at least with the 200 kc spacing, we know what
we get....although yesterday, while trying out so swl software, that every 200
was way up above 20 MHz, though it was a bright sunny day here In otherwise
perpetually cloudy NW PA....I’ll follow up,with TJ to see if that’s the
proposed fix to my neighbors system....since my antenna is 300 ft away, I may
get lucky..
Sent from my iPad
> On Jan 23, 2020, at 5:45 PM, Gary Johnson <gwj@wb9jps.com> wrote:
>
> TJ Simpson from SolarEdge was here with a crew that did their final phase of
> noise mitigation on the 6 kW system next door. Several months ago, they had
> re-routed all cabling to reduce loop areas and installed common-mode chokes
> (type 31, probably not enough turns) on the outputs of all Panel Optimizers.
> That produced no change in the interference I noted which consisted primarily
> of 200 kHz-spaced S7 noisy carriers present on most HF bands. My reference
> antenna for all measurements is a low fan dipole that is about 30 feet from
> the nearest solar panel.
>
> This upgrade involved replacement of all Panel Optimizers with their newest
> model SP350-5NM4MRM-MM25 which uses spread-spectrum communications rather
> than the previous fixed-carrier technique. It also contains type 75 ferrite
> common-mode chokes on the output conductors. The central inverter was also
> replaced (model SE7600-A). This 8.3 kW inverter has an FCC Part 15 statement
> on it. A close approach to the inverter with my DFing loop and shortwave
> radio told me that this is what I would classify as a quiet system. I would
> not expect the inverter itself to cause significant interference, based on
> personal experience investigating a great many RFI-producing devices.
>
> The 200 kHz-spaced carriers are gone as expected. Instead, there are now a
> large number of low-level signals particularly across the 20m band. They
> sound much like the old carriers though much weaker. The typical spacing
> varies widely from 3-20 kHz. The strongest ones are 10-15 dB above the noise
> floor. Those new signals are very weak on 15m an above. I did not see them on
> 40m. I would say 20m is the band that takes the biggest hit.
>
> There were only a few minutes for me to get any baseline data with the entire
> solar system completely disconnected because I didn't know the work was
> planned for that day. What I did determine is that my wideband noise floor
> across the 20m band is about 6 dB higher when the upgraded system is turned
> on. Baseline noise has no particular sonic character; it simply sounds like
> white noise. So the energy is in fact spread, albeit with those numerous
> small signals. Below 14 MHz, RFI from LED lights next door plus other sources
> completely dominates at my location during the evening hours. Therefore I
> cannot comment much on lower-frequency RFI from the SolarEdge equipment.
>
> My conclusions are: 1. When properly installed, the latest generation of
> SolarEdge Panel Optimizers can be compatible with HF radio if your antennas
> are not too close, obviously dependent upon how quiet your QTH is to start
> with. 2. The company did respond to my complaint (submitted by my neighbor),
> and did the work in good faith and at no cost. 3. TJ Simpson is in my opinion
> a reasonable and knowledgeable fellow and I'm lucky to have a human being to
> talk to at an otherwise huge, faceless corporation.
>
> Overall, my very humble home station is really no worse off than it was
> before this solar equipment was installed, since there are so many other
> sources of RFI bombarding me. Thank heavens I now have a nice, permanent,
> remote station.
>
> 73,
> Gary NA6O @W6SRR
>
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