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Bill Cypher 6mo ago

So much misinformation out there about #hamradio and solar system interference. Some systems create horrible interference and some don't. I decided to add a little bit of real test based first hand knowledge to the world instead of the usual rumors and gossip.

I recently got to go on site at a 30+ panel install using silfab panels and enphase iq8 micro inverters to test.

Strung up a spark plug gear end fed wire antenna and attached it to my #x6100 radio. Radio and antenna wire less than 50ft from the solar system. Set it to rf gain of 50 and checked every supported band, 6m to 160m. Testing was done mid afternoon on a clear sunny day and the owner confirmed that the system was running at about peak output, which by my reasoning should make any interference as loud as possible.

Background noise was S3 or quieter across all bands except 160m which was S4.

I consider that confirmation that those specific panels and inverters are not noisy when properly installed and grounded. Confident enough that I'll be getting a similar system installed on my home.

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The Beave 6mo ago

One thing that is incorrect. That is the least amount of work for the microinverters. Shade, especially from passing clouds will push the system harder and require a lot more. Also, when tapering down as batteries are full is a much more processing intensive thing to do.

Just FYI.

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Bill Cypher 6mo ago

Least work in full sun makes sense when you point it out.

I'm not sure if that makes more or less interference though.

I guess that depends where the interference comes from, which seems to be in dispute. Is it the processors or the power or the feed lines?

I may go back and test again on a shady day for more info.

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The Beave 6mo ago

The Microinverters are still using something akin to MPPT to get the most out of each panel. Of the maximum power point doesn't require calculating a new tracking tracking point due to very little short delta irradiance changes, it doesn't need to do anything and that means that the output and possibly interference generated from required changes would be very, very minimal.

Also, not driving any inductive loads is kinda cheating since it is grid tied and exporting and not directly handling possibly dirty loads from the local use.

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The Beave 6mo ago

Also, the rest of the system should be detailed. Was it charging batteries? Was it only powering constant loads in the house? Was it backed to the grid? Were the micro inverters fed into a hybrid all-in-one? All of these times matter for influencing how clean or dirty an output is.

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Bill Cypher 6mo ago

This was a grid tie system so it should be able to run full output regardless of battery existence or charge state. It definitely was feeding back into the grid when I was there.

No hybrid inverter for this design.

I plunked down my hard earned poverty paper already. Getting batteries as well for my system. So worst case once my system goes live I can really go nuts with testing anything like grid on or not and the battery system.

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The Beave 6mo ago

I'm with you. 😎 https://files.sovbit.host/media/0689df5847a8d3376892da29622d7c0fdc1ef1958f4bc4471d90966aa1eca9f2/ea15448b6b332857f5bf10696edf9fadb09e7a4867ab9ef7a2b539afcda29442.webp

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Bill Cypher 6mo ago

Fancy. I'm feeling the jealousy. Pretty sure I'll be getting enphase batteries since they have a nice package if you pair things and my installer uses their inverters. I did confirm lithium iron batteries.

Are you a ham and have you tested and documented your system for RF interference?

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The Beave 6mo ago

I DIY everything to save sats.

I'm not yet. I will be. I am not sure how to test radio stuff. I have a 1gHz channel oscilloscope, but don't know what I'd need to do to check for interface. I assume an antenna hooked to the scope and since I don't have a spectrum analyzer, use some FFT functions to try to capture anything gross?

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Bill Cypher 6mo ago

Every complaint I've seen about solar interference is in HF bands.

Simplest cheapest way I know to test would be one of the ATS Chinese shortwave radios. Common home radios don't cover low enough frequencies. I have an ATS decoder pocket but any with the full color screen should do well. Just go through the bands looking at the RSSI value. Also background noise will sound like analog TV static or an FM radio between stations. Interference will sound like a buzz or hum.

As a bonus if you get one you can listen into HF ham chatter and start learning about propogation of the bands hands on if ham radio is something you are interested in.

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The Beave 6mo ago

I have an older Boafeng UV5R that does GMRS and FRS. Would that work?

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Bill Cypher 6mo ago

Not for this. That does 150mhz roughly as a lowest frequency and you need to check 50mhz and lower.

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The Beave 6mo ago

Ah. Gotcha. One of these days I might

be able to, but that is a ways off.