[amsat-bb] The end of daytime HF?
jim at k6ccc.org
jim at k6ccc.org
Fri May 4 16:53:02 UTC 2018
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-shutdown/
>
> 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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