Hello

I throwing this out there in the hope that some people more knowledgeable than I on this matter can offer some advice. A bit of background information first.

I live in a very rural setting, in a small hamlet of 4 houses. I have been operating from my station comprising of several antennas covering 80-2m bands for some 13 years now, and have enjoyed extremely low noise due to the setting. This however changed dramatically on the 24th of Nov last year when the latest house to be added to the small cluster of dwelling was completed.

When I arrived home from a day out I turned on my radio to find a huge amount of new noise from 7Mhz to well over 30Mhz, characterized by peaks every 30khz with a signal strength of between 9 to 9/15dB. The signals are blank carriers and was led to believe are typical of wave form transformation caused by SWPS or DC Chargers etc. on SSB which I use mostly they are a constant audible tone.

This is typical display of the RFI I see on my scope from 7Mhz to over 30Mhz


To cut a long story short, I contacted OFCOM in late December who then sent an Engineer out at the start of December, and he identified the source as a newly installed Hybrid Solar PV Inverter in the new property next door, which is only 20m from all of my antennas.

Some tests were later carried out in late December, with the Solar Installer to confirm the source, and again today, more tests where done to try and identify the leak path(s) for the RF.

The outcome of the testing today seems to indicate that the DC and AC cables are both conducting RF as the noise dropped to S3 with both Solar strings isolated, and again when ferrites were clipped onto the DC cables the signal was attenuated to S6-7 mark, but only on every second signal peak, suggesting that RF was still leaking via presumably the AC side.

The problem I now have is figuring out what I need to do to mitigate and hopefully eliminate this interference. Currently the level of interference is set to end my radio activities from my property completely, which simply cannot happen. Ofcom seem to have washed their hands of the matter as they say the device complies (This is a whole other thread !!!! I personally feel that the inverter does not comply and they should invertigate but they do not appear to be interested at this time), so it is essentially down to me and the installer to figure this all out.

The inverter is (need I say it) manufactured in China, and is a SunSynk ECCO Hybrid 3.6Kw model. The Solar panels are Clear Line Fusion
335W with 7 panels in each string for a total of 252V and 10.3A per string (so the installer has advised).
From what I can gather from the research I have done so far, I would need to purchase 2 off DC EMC filters and 1 Off AC EMC filter and have these installed by the solar installers. I do not have direct access to the property as I do not know the owners, however they appear to be open to the solar engineers visiting to rectify the issue.

If there is anyone out there that has come across this particular issue before and could offer any advice it would be greatly appreciated. I feel that my case is unique, as I cant find very little help or information regarding this online. In particular I would appreciate if anyone who has experience in solar installation and/or solar RFI issues, could confirm that if I purchased 2 off Schaffner FN2200B-25-33 filters for the DC cables and 1 off Schaffner FN2090LL-30-08 for the AC side, that these would be suitable for the application, to at best eliminate this RFI or a worst attenuate it considerably? I have linked the EMC filters below. Any other alternative Filters anyone could suggest, or even further tests I could try etc. would also be welcome, along with any other helpful comments anyone may have?

Thanks in advance, and thanks for the use of this forum to seek help and discuss this issue.

Best 73's

https://www.digikey.co.uk/en/products/detail/schaffner-emc-inc/FN2200B-25-33/2187057?s=N4IgTCBcDa5gDPARgWjAVhQZiyAugL5A

https://www.digikey.co.uk/en/products/detail/schaffner-emc-inc/FN2090LL-30-08/7430584?s=N4IgTCBcDa4AwE44BlkFoDMcQF0C%2BQA

Paul,

I have seen your 'nightmare' and I have the same problem.

Hopefully your QRZ e mail is correct as I will send you details about this. I presently think at the moment I would prefer to keep it not in the public domain.

73

Peter G3VNH

details correct on my QRZ.

I realise that I've come to this topic rather late (I've just joined the site - Thanks, John M0CSN!)

Not all solar inverters are bad - just the non-compliant or falsely certified Chinese rubbish. You could find out which it is and offer to replace it with a good one. It will be a few hundred quid, but what's the hobby worth to you? I have replaced computers, SMPSs and plasma TVs in the neighbourhood in the past in order to manage the noise floor in the village

Failing that, the installation should be to EN-whatever standard meaning that shielded cable should be used where specified. A lot of cowboy installers don't do this. Of course by isolating parts of the system and inserting ferrite chokes, capacitors etc you can reduce the problem.

Ultimately you have what is pretty much a point source of noise unless it's chucking noise back into the mains supply - in which case inform the local utility company. They won't be happy about a consumer sticking RF noise into the local supply.

Have you tried putting a "noise antenna" up at your property boundary and then using an X-phase device to null it out? You can get them on ebay for about £20 for a kit or £50 for one built and I'd guess that they come up for sale on here. MFJ, JPS, DX Engineering, SEM and a load of other manufacturers make them. I had some noise on 6m from the old Cottam power station a couple of miles away to the NE from my QTH and managed to all but null it out completely from S9 to the point where I could work JAs on Es in very marginal band condx. That's with a WiMo QRM eliminator, a home made 3 ele Yagi in that direction and an El Cheapo preamp for £5 off ebay phased against my 7 ele LFA. It's a pain to set up but it can be done.

Hope that helps?
cheers
Dave

Just a thought, do they have optimisers fitted? These will give pure carriers. My next door neighbour has recently had solar panels fitted and the panels and the inverter are completely silent putting my handheld Tunsan receiver up against them, there is just the merest trace of noise, no worst than putting the receiver antenna up against a mains cable.

I do get carriers from the optimisers luckily they only appear on one frequency, 5400kHz which is a bit of a nuisance when using 5398.5kHz but it isn't very strong about S7 so the very affective notch filter takes it out completely. Of course you are hearing them over a larger frequency range the ones near me, they might be a different make.

The only suggestion if optimisers are installed is to ask the installers to temporarily disconnect them to see if the noise disappears. If that does eliminate the noise then ferrites might need to be fitted directly on the back of the optimisers, this might mean making up sort tails with the ferrite in the middle of a few turns with a plug either end so they can be fitted easier.

I have had this problem with the same system that Paul 2M0PWA mentions. It is a Chinese Sunsynk inverter that is causing all the problems. After many months of communication with Sunsynk they more or less admitted (between the lines) that their equipment was not up to standard. A new build inverter has apparently been commissioned and now fitted in my neighbours property. It has reduced noise spikes which were every 30KHz across the HF spectrum from -85dBm to -95dBm and they now say it is totally compatible and meets all the standards imposed on them. I do not believe them and my QRM remains! In England Ofcom at present do not seem to be interested in taking Sunsynk on. Within 100 yards of my property there are 8 solar systems, none of which cause any problems and within this QTH I have two European made inverters for solar.

73

Peter G3VNH

I have felt your pain from 1MHz to 50 plus MHz. Thankfully it was my solar system that caused the problems, so comunication with the installation company was easier.

The cure was ferrites (supplied by the inverter manufacturer) fitted to various wires and twisted cables between each individual solar panel and the inverters. The light bulb moment for the installation company was when I sat them in the shack watching the waterfall as the solar system was switched on / off.

(Solaredge SE8000H & SE5000H inverters. With 15kWp PV).

Good luck.

https://youtu.be/P2m6gZGtOJw?si=AIZPX6k6nUyGMTYQ

Just an quick update regarding this Solar PV Issue.

The inverter manufacturer was eventually "encouraged" by Ofcom to change the inverter for a newer design after these Schaffner RFI filters failed to mitigate the noise. The older design of this inverter model which was installed (pre Aug 2023) caused wide band interference across HF and into VHF when the receiver is in the near field (Within 200-250m it would appear). The manufacturer were well aware of this issue, and acknowledged this, however they maintained that they comply with the relevant EMC standards. (Readers can draw their own conclusions)

I have been left with no doubt that had Ofcom not of been involved from the onset, and had another amateur which I was made aware of (who had installed the same system in their own property) not logged a compliant, that the outcome may have been very different indeed. It is to the credit of the excellent Ofcom field team member who dealt with this case, and mediated with the manufacturer, that this issue was partially addressed on the 30th April 2024.

This whole episode through no fault of my own, cost me approx £300, and left me unable to use my radio equipment for 5 months. The RFI is now reduced considerably, however the 40m and 20m bands still have some RFI present, but nothing like the original inverter.

Some advice for anyone who has the misfortune of facing a similar situation....
1. First and foremost, contact RSGB EMC Help desk and seek advice then log a case with OFCOM (Even if its your own system!) Both of these entities require this data to influence further policy.
2. Contact the manufacturer and make them aware of the issue
3. If possible try and ascertain the leak path for the RFI
4. Don't waste any money trying to mitigate until the OFCOM process has run its course.
5. Don't give up. Not all Solar RFI Cases result in unfavourable outcomes

Thanks to HRD for providing this forum, and many thanks to the forum members who have taken the time to offer advice and comment.

73
Paul
2M0PWA