A little speculation:
I don't know, but doubt there are many actual 60Hz inverters out there and
they would be horrendously costly at multiKW levels, not to mention
inefficient.
Switch rates are tens of KHz, square waves, thus the noise, so the secret is
shielding and choking.
Visit all the sites you can, with a pocket radio tuned to the AM band. I
expect you'll be able to tell which are noisy.
Your dealer should be able to take you to sites with the hardware he's
selling.
And be SURE you understand your contract with your power company. They
won't pay you any more than they have to.
They will also give you a hard time about batteries, if you are in an area
where they are required to pay premium rates for green power.
Charging your batteries at off peak rate and dumping them for green rate is
NOT what they have in mind!
I know people who have batteries for backup, but they are locked out of the
outgoing circuit somehow.
WL
-----Original Message-----
From: towertalk-request@contesting.com
Sent: Tuesday, October 28, 2014 12:00 PM
To: towertalk@contesting.com
Subject: TowerTalk Digest, Vol 142, Issue 62
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Today's Topics:
1. Re: keeping the bands quiet: 12 KW PV array (Mike Ryan)
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Message: 1
Date: Tue, 28 Oct 2014 09:38:17 -0400
From: "Mike Ryan" <mryan001@tampabay.rr.com>
To: "'towertalk'" <towertalk@contesting.com>
Subject: Re: [TowerTalk] keeping the bands quiet: 12 KW PV array
Message-ID: <887E8810946D4ABFBADBECECB8A8DFEC@MichaelRyanPC>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Sooner or later I was sure I would read something on this subject on here.
It was a nightmare here for me when a neighbor decided to put in some
truck/bus batteries in his garage, and solar panels and a wind turbine over
house. He is/was using an inverter that was obviously at fault. I have some
memory of what brand it was but I could look it up to be sure. But the
neighbor here KNEW it was noisy and while struggling to figure out where
this horrendous noise was coming from with the aid of Florida Power and
Light, the guy would turn the system OFF, whenever the rfi investigator was
on our street. (Nice guy, right?) When the investigator DID finally help
me find the source (the guy) I was able to get him to put MIX 31 donuts on
his cables which reduced the noise quite a bit. However, they did not
totally eliminate the crud. After the neighbor's wife got tired of me
bothering the guy about it, I was on one visit there and asked rather
impolitely to leave the premises. A letter to the neighbor from the Tampa
FCC Field Office was met with contempt and in fact I was told that he
ignored it thinking it to be a forgery produced by me. I won't go into the
rest of the story aside from the fact that the noise is still prevalent on
the low bands, and that I can hear it in my hf mobile over 1/2 mile away.
The toroids helped a lot...I suspect with some more work with them we might
have had much greater success. Good luck and '73. -Mike, K4CVL
-----Original Message-----
From: Doug Ronald
Sent: Monday, October 27, 2014 4:06 PM
To: 'Lizeth Norman' ; 'towertalk'
Subject: Re: [TowerTalk] keeping the bands quiet: 12 KW PV array
After completing my 6.6 kW solar plant, and being initially bitterly
disappointed with the HF noise it generated, is to recommend only the use of
equipment that has an FCC Part 15 B rating. Also, if possible, keep your
antenna as far from the plant as you can. I won't go into all the boring
details of how I got the noise down to an acceptable level, but it nearly
doubled the effort. My chargers and inverters do not have any FCC rating -
big mistake.
-Doug
W6DSR
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
Lizeth Norman
Sent: Saturday, October 25, 2014 4:34 PM
To: towertalk
Subject: [TowerTalk] keeping the bands quiet: 12 KW PV array
Hi all,
Am getting ready to work with a pair of engineers and spec out a 12 KW
installation. There will be 3 poles with 14 modules on each pole. The
inverters will be at a central location in the panel area, with the AC
running 70' to the service panel.
Have spent several evenings reading various mailing list archives as well as
many other sources regarding RFI/EMI as it applies to PV arrays and ham
radio.
I've taken three things away from my research. One is spend the money on an
inverter that has a transformer in it. The second is to run as much (both AC
and DC) in conduit as possible. The third is to take care when designing the
grounding. (I WILL be using Cadwelds one
shots.)
Does anyone have any experience with PV's regarding RF noise and mitigation
strategies?
By the way, I think the whole thing can be sourced from made in USA parts.
What a concept!
Thanks,
Norm n3ykf
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