Mike Gruber, I am thinking that we need to get out to that Connecticut
Solar-Edge installation and make some 30 MHz radiated emissions measurements.
The devices probably don't exceed the limits for AC-mains conducted emissions
<30 MHz, but they may exceed the radiated emissions limits above 30 MHz, which
they are expected to meet.
Also, do make sure you have all of the contact information for Solar Edge and
your notes in good order so we can have good continuity in continuing to work
with them to get this issue more effectively resolved.
-----Original Message-----
From: RFI [mailto:rfi-bounces@contesting.com] On Behalf Of Dave Cole (NK7Z)
Sent: Sunday, October 07, 2018 1:46 PM
To: rfi@contesting.com
Subject: Re: [RFI] Solar Panel RFI in Kings Park - Update October 4th 2018
Also, at some point, take a site survey, or two, as outlined here:
https://www.nk7z.net/sdr-rfi-survey-p1/
of your RFI. Then as they make changes you can show then, and document the
changes, across a wide swath of spectrum. If you can use a non resonant
antenna it helps in getting everything as flat in response as possible. It is
all relative anyway, but the effort to make flat is always good.
I use a BWD-90, which supposedly is close to flat across 3-30 MHz as the SDR
antenna. I can now test just how flat it is, as I have a noise generator that
tests flat from 1 to 500 MHz., on my Spectrum Analyzer.
I'll set up the noise generator on a very short antenna, (as non resonant as I
can make it), antenna a block away, and see just how flat the BWD-90 is...
Then I can add correction factors to the spectrum from the SDR tests, and get
an actual set of meaningful numbers.
73s and thanks,
Dave (NK7Z/NNR0DC)
https://www.nk7z.net
ARRL Technical Specialist
ARRL Volunteer Examiner
ARRL OOC for Oregon
On 10/7/18 9:50 AM, Gary Smith wrote:
>
> They fill the optimizer with foam, the noise goes away and so do the
> techs from the solar panel company.
>
> Meanwhile, time comes and goes and the foam looses its tenacity and
> the noise comes back.
>
> Torroids are your friend not Chinese (betcha it is made there)
> synthetic foam rubber.
>
> Gary...wa6fgi
>
>
> On 10/6/2018 1:38 PM, Tony Brock-Fisher via RFI wrote:
>> /'They determined the noise to be one and the same'. /
>>
>> This is a HUGE win. Now you have them concentrated on fixing the
>> offending location, instead of spending their time spinning their
>> wheels, looking for other causes!
>>
>> I agree, the idea of 'RF absorbing foam' sounds like snake oil. But
>> if you got them to put large solid chokes on, then let them go on
>> thinking the RF foam fixed it...
>>
>> Also, improving the ground system may not help and may actually
>> hurt, if they increase the coupling of noise into the ground. It is
>> important that the ground rails do not provide a 'sneak path' around
>> any ferrites installed on cables with ground, such as at the
>> connection from the roof to the home run. Specifically, in figure 3
>> of my article, you must make sure that the bare ground conductor
>> passing thru the chokes does not make accidental contact to the rails
>> before it has exited the last choke in the string (the left hand one
>> in figure 3).
>>
>> -Tony, K1KP
>>
>>
>> On 10/6/2018 4:04 PM, Tom Thompson wrote:
>>> It won't. If you put a transmitter inside a screen room with an
>>> external antenna, it will radiate.
>>>
>>> Tom W0IVJ
>>>
>>> On 10/6/2018 1:59 PM, Tony wrote:
>>>> All:
>>>>
>>>> The RF Engineers from Solar Edger came out to my home this week to
>>>> assess the noise emanating from my neighbors solar panel system.
>>>>
>>>> They plugged into my antennas to view the spectral noise on my
>>>> receiver which they then compared to the spectral noise that
>>>> appeared on their portable setup near the solar panels. They
>>>> determined the noise to be one and the same.
>>>>
>>>> The next course of action is to improve the ground system and
>>>> install RF absorbing foam to each optimizer. I also convinced them
>>>> to replace the snap-on ferrites located at each optimizer, with
>>>> larger ones so they can loop several turns of cable around each core.
>>>>
>>>> They originally said they would just go with the RF foam which is
>>>> puzzling: I don't understand how encasing a noisy device with this
>>>> stuff could suppress RFI when the device is attached to long runs
>>>> of cable that act like antennas. Can anyone explain how that would work?
>>>>
>>>> Tony -K2MO
>>>>
>>>>
>>>>
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>>>>
>>>>
>>>
>>
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