[amsat-bb] The end of daytime HF?

[Robert Bruninga]

Great.
This is the kind of measured data we need.

And I do try to remember to tune in the AM band when I drive by a solar
house, but the RFI on AM in my electric car is so high, it is impossible
to tell whether it is comoing from the solar and power lines or my car
itself (on AM).

I know I can hear my array every XX Khz up through 10 meters (I forget the
increment) but since all of my HF dipoles have fallen, I don't have a good
benchmark, and now my neighbor has solar too, so I cant just shut mine
down for quiet.  Fortunately, my AC disconnect is right by the kitchen
door if I ever do get back on HF.

Bob

-----Original Message-----
From: AMSAT-BB <amsat-bb-bounces at amsat.org> On Behalf Of jim at k6ccc.org
Sent: Friday, May 04, 2018 12:53 PM
To: amsat-bb at amsat.org
Subject: Re: [amsat-bb] The end of daytime HF?

Well, I'll have to see how my brand new solar install sounds once it's
operational.  The 28 panels with micro-inverters on each panel are
installed, but not energized yet.  Being sunny southern California, there
is lots of solar around here - the nearest being two doors east of me.
However I'm not active on HF, so I have no basis for how the noise floor
has changed.  Since I have a couple weeks before my system can go on line
(main panel replacement required), I will hook up an HF radio to something
and try to get some before and after noise floor measurements.

Jim Walls
K6CCC
jim at k6ccc.org



On 05/04/2018 09:27 AM, Robert Bruninga wrote:
> I don't want to be an alarmist, but we need the Hams with the proper
> knowledge to get involved in this disturbing news.
>
> The National Electric Code now requires electronics on every module of
> a solar array communicating  via signalling on the DC power lines to
> assure EACH pair of panels can shut down independently.  This is to
> make all possible faults never allow more than 80 volts anywhere in the
system.
> This is effective 1 Jan 2019
>
> This is the nail in the coffin of simple DC series string arrays which
> are the quietest systems and almost demands microinverters or
> optimizers on every panel.  Refer to the QST article a few years ago
> about how disastrous optimizers are to RFI and HF operations with
modules all over the roof..
>
> Here is the Solar news:
> https://solarbuildermag.com/bos/nec-2017-module-level-solar-system-shu
> tdown/
>
> Also, what is going to happen to an array that has signaling all over
> it in the near field of HF?
>
> Although you can avoid it by going solar before then, you may have
> problems when your neighbors go later.
>
> I hate  to be an alarmist but we all know what happens when ham radio
> and commercial systems are incompatible and even though Ham radio
> might be in the right, we are only 1 in 600 and no one is going to side
with us.
>
> We took on broadband over power and squelched that dumb idea, but now
> this has the potential for equal demise of Ham radio.  It should be
> fixable, but we also know that there is high competition in the solar
> market and the modules that are made the cheapest  will be popular and
> will likely not be adequately filtered.
>
> Sorry for posting to the AMSAT-bb but it is the only HAM email
> reflector I subscribe to.
>
> If nothing else, we need to find out what systems are terrible
> emitters and nip them in the bud.  Maybe all it takes is driving by
> solar systems you see and turing on your AM radio on a weak signal
> channel and seeing if the background noise peaks near that home.  But
> also it has individual peaks, so it might also be nice to tune around
> too find the max and then check the range.  I find the noise can go
hundreds of feet along the power lines....
>
> You cant miss  em... just sounds like a 60 Hz buzz on all the
> harmonics of the inverter switching frequency.
>
> Bob
> WB4APR



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