[RFI] : Solar Panerl RFI / noise in sync with music

Sun Dec 25 20:01:44 EST 2022

I so wish the local grow lights worked that way...  :)

73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist, RFI
ARRL Asst. Director, NW Division, Technical Resources

On 12/25/22 16:17, Hare, Ed, W1RFI wrote:
> 24.998 MHz would have done just as well. 🙂
> 
> I have a funny story about that sort of thing.  A few years back, I was 
> doing a lot of HF mobile work on CW.  One day, I went way to the back of 
> a parking lot to operate.  The lot was almost empty.  A car pulled and 
> parked right next me with the car audio system blasting away, loud, with 
> the bass buzzing like most of them do.  I mean, he had a whole flippin' 
> parking lot, and he had to park right next to me.
> 
> 100W CW, 14 MHz:  CQ CQ CQ DE W1RFI/M W1RFI/M CQ CQ CQ DE W1RFI/M K
> 
> I happened to look over and he was fiddling with the controls of his 
> sound system. When I stopped, he stopped.  I let him be for a minute and 
> sent a single dit.  He jumped a bit.  Aha!
> 
> I then just sent my call, and he reached for the sound system, then 
> stopped when I did.
> 
> I started sending a string of dits and watched him fiddle, then stopped, 
> then sent dits then stopped.
> 
> Finally, he looked over at my car with the big antenna and saw my 
> pie-eatin' grin, gave me a really dirty look and drove away.
> 
> Now, if had been playing Metallica, I wouldn't have minded, but rap 
> ain't music at any volume.
> 
> There's another couple of related "immunity" stories.  I was doing BPL 
> testing in Ohio with a very cooperative BPL operator.  We were measuring 
> radiated emissions, but also looking as susceptibility.  The emissions 
> were horrible, right at the limits because he had warned the company 
> that he didn't want any trouble from "Ed." (I didn't have a last name in 
> that industry.  I decided to fire up a transmitter, 100W to a mobile 
> whip on various bands.  What I found was that if I did a brief 
> transmission, the system stopped, then quickly resumed normal 
> operation.  But if I transmitted for more than 20 seconds, the system 
> did a hard stop and the modems on each end of a leg had to reconnect 
> with each other.  So, 21 seconds of carrier and the band was pretty 
> quiet, except for bit of light clicking.  Then, after about 30 seconds, 
> I could hear modem negotiation sounds, then after about 3 minutes, data 
> started flowing again.  We found that SSB or CW slowed it down, but 
> didn't take it down. There was enough data getting through that the 
> system didn't think it had lost communication and reboot itself.
> 
> So, that afternoon, the BPL operator joined us. We were running around 
> and he was showing us how he could monitor data rates over WiFi from a 
> laptop in the back seat.  We were on a part of the system operating on 
> the 50 MHz band, so I switched the transceiver to 50 MHz CW and a 
> 6-meter antenna. When he heard how loud the noise was, about S9+10 dB, 
> he said he understood why they should not use the ham bands.  As we were 
> talking, I casually reached over and keyed the transmitter with 5 watts  
> He was in the back seat and he asked, "Hey. where did it go?"  I told 
> him that I had just transmitted on 6 meters with low power.  Let's just 
> say his expression was colorful and very holy. I then told him that if I 
> transmitted for 21 seconds, his system would be down for about 3 to 5 
> minutes.   He asked me to demonstrate. I did, and it did just what I had 
> seen at other parts of his system.
> 
> He ultimately did resolve all of the interference problems by careful 
> choice of frequency, but he was plagued with intemittencies all along as 
> various VHF operation took the system down.
> 
> Now, this one has a followup.  FPL in Florida set up a BPL trial area.  
> A ham was squarely in the trial area, so he contacted me and asked what 
> he should do.  He had about S9 noise across several bands.  I told him 
> how and why he should complain, but I also told him the story that had 
> happened in Ohio.  I went on to explain that if he operated SSB or CW, 
> he'd slow the system down, but that FM or digital operation would take 
> it down hard.  He wasn't a CW op, but he said that he was very 
> interested in learning digital operation. So, he set up a 10-minute brag 
> tape and get himself all set up to do PSK-31.  PSK-31 was robust enough 
> that he was able to make contacts, and he said that he was having so 
> much fun that he operated for hours nearly every night.
> 
> Several months later, they shut down the trial. He talked iwth the 
> engineer who was in charge of the system, who told him that the system 
> just wasn't reliable, because it would stop working for hours on end in 
> the evening when everybody was home using it.
> 
> And that's another story that never made it to the pages of QST!  I got 
> 37 years worth of them! LOL!
> 
> Ed, W1RFI
> 
> ------------------------------------------------------------------------
> *From:* RFI <rfi-bounces+w1rfi=arrl.org at contesting.com> on behalf of 
> Dave (NK7Z) <dave at nk7z.net>
> *Sent:* Sunday, December 25, 2022 6:48 PM
> *To:* rfi at contesting.com <rfi at contesting.com>
> *Subject:* Re: [RFI] : Solar Panerl RFI / noise in sync with music
> Did you by chance transmit on that frequency, while the thing was on?  :)
> 
> 73, and thanks,
> Dave (NK7Z)
> https://www.nk7z.net <https://www.nk7z.net>
> ARRL Volunteer Examiner
> ARRL Technical Specialist, RFI
> ARRL Asst. Director, NW Division, Technical Resources
> 
> On 12/25/22 12:09, Henry Pfizenmayer via RFI wrote:
>> Mike  et al ---If that was not tongue in cheek as they say -- this last summer I started getting thumps of
>> 
>> noise  on 6 meters -and was far worse at 25 mhz --  Then I noticed it was in sync with neighbors outside
>> 
>>   speakers  thumping out a strong bass line.  I went out with my IcomR10 rx and loop -
>> and yep that was the source. The amp was obviously going into oscillation in sync with the loud bass notes .
>> No use talking to that guy - so I just prayed the damn amp would fry itself . Prayers were answered
>> 
>> in just a hour or so and noise never re-appeared.
>> 
>> 
>> 
>> 73 Hank K7HP
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> Message: 1
>> Date: Sun, 25 Dec 2022 11:51:20 -0500
>> From: Michael Martin <mike at rfiservices.com>
>> To: "Dave (NK7Z)" <dave at nk7z.net>
>> Cc: Rfi List <rfi at contesting.com>
>> Subject: Re: [RFI] Another Solar Panel RFI System
>> Message-ID:
>> <CAPZkRSEvyTNyLcJT-3e1gNnkTP+WNX15DFXUXHpqf5YZa67YEw at mail.gmail.com>
>> Content-Type: text/plain; charset="UTF-8"
>> 
>> I'm trying to capture a noise with the intermittency rhythm in sync with
>> Christmas music
>> 
>> Michael Martin
>> RFI Services
>> 51 W Bay Front Rd
>> Lothian, MD 20711
>> 
>> 240-508-3760
>> mike at rfiservices.com
>> www.rfiservices.com<https://webmail.centurylink.net/app/www.rfiservices.com 
> <https://webmail.centurylink.net/app/www.rfiservices.com>>
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