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Re: [RFI] Solar system noise

To: Gordon Anderson <gaa@owt.com>, Frank W3LPL <donovanf@erols.com>, cwops@groups.io, reflector RFI <rfi@contesting.com>
Subject: Re: [RFI] Solar system noise
From: David Hachadorian <k6ll.dave@gmail.com>
Date: Wed, 20 Mar 2024 09:57:24 -0700
List-post: <mailto:rfi@contesting.com>
I'll cross post this reply to the RFI Reflector.

My neighbor's solar system was provided by Solar Edge, and was installed by Titan Solar.  As soon as it was turned on for testing, I could see that it was extremely noisy - too noisy for me to continue contesting.  I contacted ARRL, and as it turns out, they had a good technical point of contact at Solar Edge.  To make a long story short, two months later Titan Solar showed up again at my neighbor's house, and I watched them unload three heavy cardboard boxes from Solar Edge.  The techs worked all morning installing whatever it was, probably ferrites.  At the end of the day, the characteristics of the noise had changed considerably, but were not cured.

As it turned out, my neighbor had also installed a new digital device in her house, which wreaked havoc on large swaths of all bands, especially 15 and 20.  I could tell that this was not caused by the solar system, because when the neighbor occasionally went away for the weekend, the noise would disappear, even though I could see that the Solar One Inverter's on-line light was illuminated.

To combat the new noise, I purchased two (for SO2R contesting) MFJ 1026 Noise Cancellation Units, and installed a homemade WD8DSB portable flag antenna just a few feet from my neighbor's house, on my side of a block wall.  I used an inexpensive 30 dB preamp to amplify the weak output of the small loop. https://www.amazon.com/gp/product/B01N2NJSGV/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 The RF output of the preamp was tee'd off to the noise input of the two MFJ boxes.  That setup has proven to be quite effective, but it is cumbersome to keep adjusting the MFJ boxes for different frequencies and even different beam headings.

Now my neighbor has sold her house, and should be moving shortly.  I am really looking forward to that day!  Hopefully the new neighbor won't have any loud noise sources, but these days it's a crap shoot.

Dave Hachadorian, K6LL
Yuma, AZ




On 3/19/2024 9:42 PM, Gordon Anderson wrote:
Hello,

I posted a message describing a noise problem I am having with my neighbor’s solar system and Frank, W3LPL, gave me your contact information. He said you found / developed a noise calculation solution, I would be interested in anything your will to share. I attached my posting below.

Thanks!

—Gordo, KG7YU

Hello,

I am looking for some advice on a noise problem I have been dealing with. My neighbor installed a solar system. His house is right next to me on our east side. My tri-band beam points right over the top of his house. I have attached a picture of the band scope so you can see the noise pattern. The noise band is about 4KHz wide and repeats about every 30KHz. I see this on all HF bands. The interesting thing is this noise band is not stationary as you can see in the picture, it wanders around. My neighbor is also my son, we know his system is the source because if we pull the disconnect and shut it down all the noise disappears. As you would expect we only see the noise in daylight hours.

The system uses Chilicon Power CP-720 inverters, one for each pair of panels and they are mounted under the panels.

I have a noise cancelation system that seems to work well on 40 meters, I have not had any luck on 20 meters, likely due to the noise antennas poor performance picking up the noise on 20 meters and up.

We have not yet contacted the installer or the manufacture, I expect this is be an uphill battle and wanted to first look for a solution and learn from others experience.

Running is very difficult with this noise; it will wander through my frequency every few minutes making is very challenging. My current plan is to find a noise antenna I can place close to the source and try to cancel it. We are also going to search for a specific “hot” spot on his system, this is not easy because we really need a band scope to find the noise due to the fact that it is not stationary.

My feeling is I will have more of these issues as time marches on and more of my neighbors install solar.

Any input would be very helpful!

--Gordo, KG7YU

IMG_5237.jpeg

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