[aprssig] FW: Solar Ham Radio Interference

KF4LVZ aprssigZbr6 at acarver.net
Sat Nov 19 00:59:23 EST 2016

You can't use string inverters on an array that receives partial shade
otherwise your array efficiency will be lower.

On 2016-11-18 17:11, Robert Bruninga wrote:
> Previously QST and my emails discussed the rise in the noise floor from home
> solar and my suggestions to avoid purchasing a system with micro-invrters or
> elecronic "optimizers" on every panel on the roof, and stick with the
> wuieter or easier-to-fix all DC wiring and central inverters.
> THAT’S NOT ALL!   It was pointed out at the ARISS meeting this weekend that
> one must also watch out for their NEIGHBORS!  That is, if you want to keep
> your clean noise floor for your own hamming and your own solar, you must
> also be vigilant of your surrounding neighbors.
> The time to make friends so you can guide their future investment is NOW,
> well in advance before they make an irreversible decision.
> Ill try to remember to go out and see how far the noise radiates from some
> of the other solar panels in my neighborhood.  Although my DC system with
> central inverters is much quieter, I should go out and see how far beyond
> these houses, the various system's interference can be detected.
> Bob, Wb4APR
> -----Original Message-----
> From: Robert Bruninga [mailto:bruninga at usna.edu]
> Sent: Sunday, October 23, 2016 12:55 PM
> To: Amsat BB
> Cc: bruninga at usna.edu
> Subject: Solar Ham Radio Interference
> Not Satellite related, but people often ask about any RFI from my solar
> arrays at home.  Interest stems from an RFI issue in April QST and my letter
> in Sept 2016 QST.
> Well, FINALLY, the jury is in.  For the first time since installing solar, I
> finally got all my full-sized dipoles up in the air again. And listened with
> the arrays on and off.
> Yes, I have inverter noise about 12 dB above the noise floor every 38 kHz on
> 80 meters,. But couldn't really find anything on 20 meters.  I did not do a
> thorough search, but enough to finally say, "yes, there is some noise..."
> I post this because my 16kw of arrays are conventional series string arrays
> and much quieter than the  "optimizers" on every panel all over the roof
> noted in the April QST article.  I always thought my string array was quiet,
> but now I have some data noted above.  This could easily be fixed with some
> clamp-on ferrites down in the basement on the wires going into the
> inverters...
> But for my rare HF operating, the solar AC disconnect switch is about 3 feet
> from the kitchen door.  Easy enough to pull if I want HF silence.  I could
> also install a 40 amp disconnect relay from a switch in the shack...  But
> with my rare operating style, I'll probably do nothing.  Of course it is
> perfectly quiet at night ;-)
> It took me 6 years to get around to this test, so don't hold your breath
> waiting for me to add some clamp-on filters to the inverter wires and see
> what that does.
> For those into solar, come join us on SolarDIY at yahoogroups.com Bob, WB4APR

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