[amsat-bb] Solar RFI?

[Norm n3ykf]

Good installation practices are key. Try to force contractors going
for the bottom line to use good materials and practices.
Not a chance.
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On Tue, May 9, 2017 at 11:49 AM, Greg Stahlman <kj6ko at innercite.com> wrote:
> Problem is, solar MFGR’s are exempt from Part-15, BUT, the operators are not!  At least that’s the way I read it.
>
>
>
> 100uV/M is a LOT!  Especially when trying to run weak signal stuff!   My neighbor’s is about 18db over night time noise floor!
>
>
>
> I heard good things about “Micro Inverters” vs the more common “Optimizers”, which are basically a DC-DC converter on the back of the panel, and they were right!  I had a 7KW system put on my roof but demanded they use  Microinverters and I hear NOTHING!!   Very quiet!
>
>
>
> The Optimizers are a HUGE nuisance from 80M through 6M and even on 2M.
>
>
>
> Regardless if they fall under the 100uV/M, the main rule of Part 15 states simply  “…must not cause harmful interference, even if it results in the improper operation of the interfering device.”
>
>
>
> 73
>
>
>
> From: AMSAT-BB [mailto:amsat-bb-bounces at amsat.org] On Behalf Of Robert Bruninga
> Sent: Tuesday, May 09, 2017 7:30 AM
> To: amsat-bb at amsat.org
> Subject: [amsat-bb] Solar RFI?
>
>
>
> RFI from Solar?
>
>
>
> With solar now cheaper than coal, solar is exploding in to neighborhoods
> with favorable progressive policies.
>
> But, they can produce lots of RFI with significant impact on Hams operating
> HF.
>
>
>
> With 16 kW of solar on my roof, I feel in a good position to be proactive
> in documenting the overall impact of solar on HF operations.
>
>
>
> We’ve seen QST articles on the very high RFI levels from solar systems that
> use microinverters and optimizers located at every single panel on the roof
> which are a nightmare to filter, while string inverters are easy to filter
> at the one location on the ground.
>
>
>
> My thoughts are to come up with a standard test that Hams near solar
> installations can do to document any RFI.  Although none of us will have
> standard calibrated antennas or receivers, we can at least make comparative
> measurements to background noise levels.  Either with the array on and off
> or between day and night at a fixed distance from the array.
>
>
>
> I believe the part 15 limits for unintentional radiators is for 100 uV/m at
> a distance of 30 meters (100 feet).  On a 1 meter portable antenna I
> calculate that is equivalent to 36uV or within a dB of S9.  That’s a lot of
> noise (if I did that right)…
>
>
>
> And if it was a full size dipole say on 20m, then the allowable noise would
> be 20 over S9 (again, if I did that right) Wow.
>
>
>
> If anyone wants to submit measurements Ill collect them.
>
>
>
> My suggestion is to take a portable HF rig (FT-817 or TH-F6 or TH-D74) and
> an approximate 1m whip antenna and report at 100 feet from the array, the S
> readings with the array on and with it off (or day vs night).
>
>
>
> I welcome more expertise in this area.  Although this is not an AMSAT
> issue, this is the only email group I’m on that might have people with
> those easy portable HF radios.
>
>
>
> Bob, WB4APR
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