[RFI] Another Solar Panel RFI System

[David Eckhardt]

Ed Hare, et.al:

The FCC already has a line in the sand by dictating limits to which
radiated and conducted emissions must stay below.  That's what we measure
for such parameters in an accredited lab to assure the equipment is at or
below those prescribed limits in field strength (including the QP
"average") and applied a bit differently for conducted emissions.  You also
measure against these limits in your lab at ARRL.

QUOTE:  " I don't recall the FCC EVER having regulations that set a level
of harmful
                inteference. Do you have copies of those old rules?"

Limits and test methods are well described in CFR-47 and vary by the type
of equipment.  We are most familiar with Part 15 for both intentional and
unintentional radiators.  We also play to Part 18 which addresses ISM and
medical equipment.

There are limits in place and have been for some time.  The level set by
FCC *in their opinion* (when FCC had some smarts in OET) reflects a
tolerable level of "harmful interference".  The original set levels (for
various differing RFI producers) was established based on many tests of the
time (in the 1950's).  As previously stated in my last email, those limits
were tightened at the beginning of the "digital age".  I well remember many
commercial products struggling with the lower limits when that was put in
place.  One in particular, I well remember as I once owned and played an
Allen "Digital" church organ.  The original design was done in "secret" by
Rockwell International in Anaheim, Ca., where I worked at the time.  When
the Part 15 limits were tightened, they went through a major redesign in
packaging the digital circuitry to comply with the tightened FCC limits.  I
was part of that.

So, there are and have been for some time, limits put on radiated and
conducted emission which, *in the opinion of the FCC*, reflect a
"tolerable" level of "harmful interference".

Ed, I don't' mean in any way to be confrontational, but this is the history
of Part 15 and other parts of CFR 47.   I well understand your stance and
agree with not placing a limit on "harmful interference".  In effect, FCC
already has limits *per their judgements* of what constitutes "harmful
interference" based on 1950's technology.  Maybe what I'm proposing and
requesting is a hard definition of specifically what constitutes "harmful
interference".  That is the other end of the harmful interference stick.
The real-world definition of "harmful interference" is left undefined in
most of CFR 47.  With that, no one could in their right mind throw out the
statement that S-9 does not constitute "harmful interference".  All us hams
know otherwise!

Another question:  True, the solar power industry must comply with CFR 47,
Part 15, as an unintentional radiator (without wireless, ZigBee or what
ever to control of the system......that's handled by by approval of an
intentional radiator and must bare reference to the FCC ID on the
product).  Then why are there so many legitimate reports of "harmful
interference" to amateur radio (and other services - I presume)?

I give ARRL nothing but accolades for working with Solar Edge.  But why
haven't we seen any progress in their recent installations?  On this online
group, this has been going on for at least 2-years.  I realize money is an
issue, but they are selling and installing a product which would be
considered illegal to place on the market.  ARRL has confirmed that.  Are
the installers or Solar edge held responsible in light of the FCC rules?

There is a huge solar farm at the entrance to DIA east of Denver (I' live
in N. Colorado).  True, it's a busy airport, but on driving past that solar
farm, I do not notice much, if any, additional interference due to the
presence of that solar farm.  It can be done, but not likely with Solar
Edge equipment and installers.

Dave - WØLEV

On Mon, Dec 19, 2022 at 12:52 PM Hare, Ed, W1RFI <w1rfi at arrl.org> wrote:

> <What constitutes "harmful interference" and how does one put a
> quantitative
> and consistently measurable method and tool in place to make that
> measurement?>
>
> We do NOT want a quantitative definition of harmful interference.  Firat,
> if the FCC were to set that criterion, we would not like the level that was
> set.  In all of the cases ARRL handles directly with the FCC, we base our
> assessment of harmful interference on a number of factor, such as:
>
> o The frequency
> o The environment
> o Antenna gain and separation from the source
> o The presence of an identified single source of interference
> o The practicality of correcting the interference
>
> By not demanding that FCC draw a line in the sand, we have successfully
> engaged the FCC on a number of cases of lower-level interference, just
> because the source was known and the cure was relatively simple and
> practical.
>
> The insistence of some amateurs that a specific level be cast in stone
> ever perplexes me.
>
> <In the 1950's FCC placed field strengths with limits on that parameter
> and
> measurement methods which, at the time, were intended to represent "harmful
> interference".  >
>
> I don't recall the FCC EVER having regulations that set a level of harmful
> inteference. Do you have copies of those old rules?
>
> <Further, there are no regulation on the solar power industry, in
> general. >
>
> Solar systems must meet the Part 15 limits for radiated emissions above 30
> MHz and for emissions conducted onto the AC mains below 30 MHz.   The
> operators of solar systems must use them in a way that doesn't cause
> harmful interference to licensed radio users.
>
>
> Ed Hare, W1RFI
>
>

-- 
*Dave - WØLEV*