Great read about Enphase. I had an 8 KW Enphase system installed about 6'
below my Cobweb antenna. Didn't put any ferrite on any of the leads. I
lived in Southern CA at the time and peak output would hit around 6.9KW in
Aug & Sept. Had zero RFI issues both on TX and RX, I couldn't tell if the
system was on or off. Nice system.
73! Mark KA6WKE - DM34st
Youtube: https://www.youtube.com/ka6wke
Website: https://www.ka6wke.net
LinkedIn: https://www.linkedin.com/in/markschoonover
On Tue, Jul 19, 2022 at 8:47 AM K9MA <k9ma@sdellington.us> wrote:
> My next door neighbors recently installed a solar system, with the
> panels no more than 60 feet (18 m) from my antennas. The primary antenna
> is a tribander at 70 feet, with a 40 meter rotatable dipole 6 feet above
> it. I'm in an urban area, surrounded by overhead power lines, so the
> noise level is fairly high. At best it's about -130 dBm/Hz on 20 meters.
> So far, I have been able to detect no RFI from the solar system from 1.8
> to 28 MHz. Details below.
>
> The solar system consists of 14 320W panels, each with an Enphase IQ7+
> microinverter. It is a grid-tied only system, with no batteries or
> standalone operation.
>
> At my request, ferrite snap-on split cores were installed. Each short DC
> lead from panel to inverter had two Fair-Rite 0431178281 cores attached
> near the inverter. On the AC cables, Fair-Rite 04311164181 cores were
> used. On 9 of the inverters, one core was attached the the input lead
> and one to the output. On the remaining 5 inverters, a core was attached
> only to the output lead. (Two, at the ends of the chains, had no input
> connection, and I ran out of cores for the other 3.) One additional core
> was attached to each AC cable to the junction box, about 5 feet from the
> closest inverter.
>
> I checked out a couple other Enphase systems in the area with a small 20
> meter loop and preamp. No RFI was detected but, of course, the small
> antenna is not very sensitive.
>
> There is no way to know from this data whether all the ferrite cores
> were necessary. Even if they were, however, it shows that fairly simple
> and inexpensive mitigation measures are adequate with this Enphase
> system, at least in an urban noise environment.
>
> Both the neighbors and contractor were very cooperative. I paid for the
> $300 worth of ferrites, in the interest of maintaining good relations,
> but I shouldn't have had to do that. If the contractor had had to remove
> all the panels to attach the cores after the panels had been installed,
> it would have cost them much more than that. If I were to install my own
> Enphase system, or if another close neighbor were to, I would insist the
> installer pay for the ferrites and install them initially, or agree to
> retrofit them later if necessary. I would, however, waive my customary
> enormous consulting fee.
>
> 73,
>
> Scott K9MA
>
> --
> Scott K9MA
>
> k9ma@sdellington.us
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