[RFI] Soliciting Help From Certified RF Engineer

Wed Sep 2 11:53:45 EDT 2020

Yes, harmful interference is the basis on which the FCC Enforcement folks resolve almost all of the complaints it receives.  If three is an emissions violation, that gets handled by the Office of Engineering and Technology, which would move this out of the enforcement arena.  If EB received a report with technical measurements, it would send it to OET for evaluation, and if they came back and said that the test did not show a violation, but showed noise 20 dB below the Part 15 limits for intentional emitters, I suspect that EB would decide then and there that this is not harmful interference.

The other basis on which to compare noise levels would be to compare the noise to the median values of man-made noise in residential environments described in ITU-R P372.XX.  Those levels are also uncomfortably high and if FCC determines that the measured levels are  below that median value of man-made noise, that would be game over for harmful interference and it would possibly advise Solar Edge of that.  

>From all indications, Solar Edge complies with the limits for conducted noise onto the AC mains.  The exact amount of radiation depends on a lot of factors, but by my calculations, a just-legal conducted noise on HF would be about S7 to an amateur with typical antennas located 30 meters from the house.  That would be from a legal system, other than the fact that we can usually make a case that S7 noise is harmful interference. Under the rules, the manufacturer of the device must meet the emissions limits and the OPERATOR of the device, typically a neighbor, is responsible for harmful interference. Solar Edge is assuming that responsibility on behalf of its customers and is continuing to work towards engineering solutions to the few problems remaining after correcting about 250 systems to the satisfaction of the involved amateur.

Ed

-----Original Message-----
From: EDWARDS, EDDIE J <eedwards at oppd.com> 
Sent: Wednesday, September 2, 2020 11:30 AM
To: Hare, Ed W1RFI <w1rfi at arrl.org>; Tony <dxdx at optonline.net>; Rfi List <rfi at contesting.com>; Tony Brock-Fisher <barockteer at aol.com>; Cianciolo, Paul, W1VLF <pcianciolo at arrl.org>
Subject: RE: Soliciting Help From Certified RF Engineer

Ed,

You compared Tony's problem to Broadband over Power Line (BPL) which was adding computer network data over the power lines (and is dead now), but wouldn't Tony's situation with Solar Power electrical generation be more like RFI over power lines carried over the electrical power grid?  Wouldn't Part 15's "harmful interference" to a licensed radio service apply here?  

Solar power is simply electrical power generation being carried over power lines within the home, and in some cases being back-fed to the electrical distribution system.  If the system creates RFI and carry's it over home power lines, how is this different from spark gap noise over distribution lines to the home other than a different owner of the equipment?  

If power company's ever caught wind that they can stop repairing RFI problems because they meet RFI conduction limits below 30 MHz, that'll surely and eventually be the end of HF operations nationwide. 

It seems that the next step here is an ARRL letter to the neighbor about the RFI problem that the neighbor can pass along Solar Edge pointing out that it still causes Part 15 Harmful Interference that needs to be resolved.  

If you're really suggesting Tony (and everyone else) wait until the W1VLF testing and repairs are completed to determine if that will be the repair moving forward, then the letter should indeed wait for that event to happen first.  Just let us know that.  

Just curious why you chose to reference the dead technology BPL instead of spark gap power line noise? 

73, de ed -K0iL

-----Original Message-----
From: RFI <rfi-bounces+eedwards=oppd.com at contesting.com> On Behalf Of Hare, Ed W1RFI
Sent: Wednesday, September 2, 2020 9:46 AM
To: Tony <dxdx at optonline.net>; Rfi List <rfi at contesting.com>; Tony Brock-Fisher <barockteer at aol.com>; Cianciolo, Paul, W1VLF <pcianciolo at arrl.org>
Subject: Re: [RFI] Soliciting Help From Certified RF Engineer

You can do this, Tony, but it could be counterproductive.  Under Part 15 rules, there are no specific emissions limits for radiated emissions for unintentional emitters below 30 MHz.  All indications are that they comply with the conducted emissions limits that do apply.  There are separate emissions limits for intentional emitters, including carrier-current devices such as broadband over power-line devices.  The limits for intentional emitters do include radiated emissions limits  below 30 MHz.  Those limits are, however, approximately 30 dB higher than the (unregulated) radiated emissions that typically occur from legal conducted emissions.  In our experience with BPL, those "legal" carrier-current emissions were typically about S9+10 dB or so to mobile units on the roads and nearby amateurs with effective outdoor antennas.  If you get those measurements made, you can probably extrapolate from the S9+10 to your own noise level in the AM mode to estimate how far below any radiated e  missions limit that applies to other types of devices their noise is.  Once this escalates to the level you are suggesting here, this may well get turned over to their attorneys who will quickly figure out that the report does not show any violations of emissions limits in any way.

Solar Edge is scheduled to install a replacement inverter at W1VLF and it remains to be seen what impact that will have on noise levels.  That could or could not be a game changer, so I really hope that nothing short circuits that process.  It could well be that Solar Edge has provided all of the solutions they have at this time, but they are also working with Paul on possible improvements.  We will know when that is done how many dB improvement to expect from what could be a new EMC solution.

Engineers qualified to make those measurements using calibrated equipment are typically going to charging about $100 per hour, including travel time, plus the same amount to write up a comprehensive report of their measurements.  

Ed Hare, W1RFI
ARRL Lab

-----Original Message-----
From: Tony <dxdx at optonline.net>
Sent: Tuesday, September 1, 2020 8:49 PM
To: Rfi List <rfi at contesting.com>; Tony Brock-Fisher <barockteer at aol.com>; Hare, Ed W1RFI <w1rfi at arrl.org>; Cianciolo, Paul, W1VLF <pcianciolo at arrl.org>
Subject: Soliciting Help From Certified RF Engineer

All:

As many of you know, I received an email from Solar Edge stating they've exhausted all known remedies to resolve the RFI caused by their solar panel system.

They believe their devices are now noise-free yet they've NEVER been to the site to see the marginal affect their work has had on the level of interference. They instead rely on yours truly to report back after work is done.

At this point, I believe the only option is to solicit the help from an RF engineer to assess the interference and send a report to Solar Edge. 
That should carry more weight than the video proof and other material I've provided.

I suspect we have some RF engineers that might be willing to help so I've listed my contact info below.

Tony -K2MO

Tel. 631 656 9151
Email: dxdx at optonline.net

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