Ed, et al,
Thanks for these Christmas "presents"!
73,
J. Gordon "Gordie" Beattie, Jr., W2TTT
201.314.6964
W2TTT@ATT.NET
Gordon.BeattieJr@VIAVISolutions.com
Get On The Air!
________________________________
From: RFI <rfi-bounces+w2ttt=att.net@contesting.com> on behalf of Hare, Ed,
W1RFI <w1rfi@arrl.org>
Sent: Sunday, December 25, 2022 7:17:16 PM
To: nk7z@arrl.net <dave@nk7z.net>; rfi@contesting.com <rfi@contesting.com>
Subject: Re: [RFI] : Solar Panerl RFI / noise in sync with music
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@contesting.com> on behalf of Dave (NK7Z)
<dave@nk7z.net>
Sent: Sunday, December 25, 2022 6:48 PM
To: rfi@contesting.com <rfi@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
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@rfiservices.com>
> To: "Dave (NK7Z)" <dave@nk7z.net>
> Cc: Rfi List <rfi@contesting.com>
> Subject: Re: [RFI] Another Solar Panel RFI System
> Message-ID:
> <CAPZkRSEvyTNyLcJT-3e1gNnkTP+WNX15DFXUXHpqf5YZa67YEw@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@rfiservices.com
> www.rfiservices.com<https://webmail.centurylink.net/app/www.rfiservices.com>
> _______________________________________________
> RFI mailing list
> RFI@contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
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