Well put, Ed. However, addressing each reported RFI problem on a
case-by-case basis is labor intensive. But, your statement and implied
caution to all amateurs is the term " personal diplomacy".
We as hams don't like to tolerate *any* additional interference over
anything we might remember from yesterday, last week, last month, last
year, or...... We tend to react (maybe human nature) in a confrontational
manner (Yes, I've been there as well). This is not what ARRL and FCC
desires or is willing to address. Keep your cool. Do you homework on
isolating the problem. Write up a report with good data and communicate
the problem with a cool head. First and foremost, file your report through
ARRL, not initially to FCC. Our dues to ARRL pay for this service. As
members, use it!
I've been a licensed ham for 63 years and cut my teeth on vacuum tubes.
I've seen the noise floor at the "green end" of the HP 8566 spectrum
analyzer (once the mainstay of accredited test labs) increase from pretty
insignificant levels to 40 dB over dummy load due to incursion of all the
RFI created by our digital devices. Following on the heals of the "digital
revolution" came the SMPSs (maybe in reverse order). Then came the influx
of RFI generators (many would not pass FCC standards) from China. Then
came solar power. Next will be electric cars with their (proposed)
outrageous charging systems. So, I'd estimate in the cities, the noise
floor has increased some 40 dB over what I remember from 6 decades ago
(well before the industry had any really good spectrum analyzers on the
market - remember the HP 141T?).
I still believe the standards should be revisited wrt radiated emission
levels and measurement philosophies. Pegging interference potential on
single-frequency field strength levels has become inappropriate in this
digital age. This worked fine in the 1950's and onward, but the present
interference potential as a result of the digital revolution no longer
deals with single-frequency emissions. A good square wave clock - just the
clock alone - alone produces harmonics on all odd multiples of its
fundamental frequency to the limit of the speed of the silicon. Now the
clocks are spread or "smeared out" over a limited frequency range to dodge
the field strength philosophy of assessing interference potential. A new
method and measurement philosophy more suited to evaluating the
interference potential of the digital world is in order. But I'm loath to
sitting on committees which make these decisions.
Enough......
Dave - WØLEV
On Fri, Dec 23, 2022 at 8:36 AM Hare, Ed, W1RFI <w1rfi@arrl.org> wrote:
> To my knowledge, the senior staff at FCC have pretty much let the
> Enforcement Bureau do its job. Laura Smith has pretty much said, in one
> case from a ham who literally demanded an answer from her, that the FCC
> would not consider S3 noise to be harmful interference in a residential
> environment, but the HQ staff did manage to make it clear that this still
> needs to be evaluated on a case-by-case basis. If the Chair had dictated
> that S9 was not harmful interference, then Smith would be stuck with that,
> which she is not.
>
> Now, hams would make the case that S3 noise can be interference, and it
> can be, but the ITU-R has done decades of studies that show that the median
> value of human-made noise is more typically S6 in residential environments,
> so FCC knows that if it were to take firm enforcement action, it would
> probably not prevail with the ITU-R document pretty much saying that a
> higher-level is typical. The attorney for the defendant would bring that
> out quickly.
>
> Having said that, I know that Solar Edge is pretty much down to that level
> with its current designs. We still see issues, with legacy systems out
> there and with new systems and poor installation practices by the many
> installers doing the work. Solar Edge is again going to try a new design
> it believes will be even quieter, so "big business" is not the automatic
> enemy and when we get cooperation of any sort, we are better off working
> with it and building on it than we are trying to fight it.
>
> FCC is also rather cooperative, taking ARRL's well-vetted reports and
> issuing advisory letters to operators of noisy devices. Even in cases of
> "S3" interference, when we can identify a single source of noise and
> demonstrate that it can be fixed, FCC has asked operators of these devlces
> to work with the amateurs to try to resolve it. We are honest with the FCC
> about the level of interference, but its staff have been sympathetic so far
> to the concept that if interference can be reasonably fixed, it is
> reasonable to ask for manufacturer or operator help in doing so. That is
> far more advisory than the usual letter, by necessity, but the FCC has been
> very helpful to us in trying to get cases resolved.
>
> The key to these "lower levels" of interference receiving FCC
> encouragement hinges on the premise that the source can be reasonably fixed
> even though it is weak. That has been decided on a case-by-case basis,
> sometimes unfavorably to amateur radio, when the possibility of a
> reasonable fix is not immediately clear, or in some cases, where an amateur
> has made loud and sometimes too forceful demands that the FCC do just what
> the ham tells them to do.
>
> More than the technical solutions, what I call "personal diplomacy" is a
> key to solving any RFI problem.
>
> Ed Hare, W1RFI
> ARRL Lab
>
>
> ________________________________
> From: RFI <rfi-bounces+w1rfi=arrl.org@contesting.com> on behalf of Steve
> Dyer W1SRD via RFI <rfi@contesting.com>
> Sent: Sunday, December 18, 2022 3:09 PM
> To: rfi@contesting.com <rfi@contesting.com>
> Subject: Re: [RFI] Another Solar Panel RFI System
>
> Randy,
>
> What is the source of this statement?
>
> I find it unlikely the FCC Chair is commenting so specifically on this
> issue.
>
> If she is so familiar with this issue as to comment at this level of
> detail, then it presents an opportunity to engage directly.
>
> 73,
> Steve
> W1SRD
>
> On 12/18/2022 11:56 AM, wx5l@charter.net wrote:
> > Recently Jessica Rosenworcel , FCC chairwomen has made a statement about
> > issues with Solar Edge RFI and said that S-6 to S-9 is NOT harmful
> > interference.
>
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>
--
*Dave - WØLEV*
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