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Re: [RFI] Mystery Noise (Aren't they all)

To: rfi@contesting.com
Subject: Re: [RFI] Mystery Noise (Aren't they all)
From: Pete Smith N4ZR <pete.n4zr@gmail.com>
Date: Wed, 27 Mar 2024 17:51:26 -0400
List-post: <mailto:rfi@contesting.com>
Unfortunately, the multi-step procedure you describe has been the case everywhere I have lived - it would be nice if the repair crews could at least give us a chance to listen when they're done repairing.

73, Pete N4ZR

On 3/27/2024 5:01 PM, Wes Stewart via RFI wrote:
  As promised, a follow up. There has been no improvement in my situation. One major problem 
is the way the electric coop operates; the RFI guy finds a suspect, contacts someone else who 
is supposed to dispatch a crew to address the issue.  If the repair people show up, they 
do something that may or may not correct the problem and then go away.  I wait a few days 
and then follow up to find nothing is resolved.  Rinse and repeat.
One thing that has happened is that I contacted our water coop that owns the pumps that are 
supplied by the electric coop.  After several fits and starts I was able to get the RFI 
on site while a water guy turned off the variable frequency motorized pumps.  The RFI was 
unchanged.  This is unfortunate, I was hoping it was a pump because I think the water 
guys would be more cooperative than the electric guys.
So as it stands the RFI guy came to my shack again and hooked his Radar Engineers RX 
to my antenna.  I took a short iPhone video of what is heard and displayed.
https://www.dropbox.com/scl/fi/rvjv8nf1eoj8w75stltx6/Radar_Engineers_Video.mp4?rlkey=n5y7ddr8odb7mw4cl68ckmx81&dl=0
Note that the strength indicator is showing -47 dBm.  S9 is standardized to -73 
dBm.  So this is 26 dB over nine, which is about what I measure.
Wes  N7WS


     On Thursday, March 7, 2024 at 12:51:51 PM MST, Wes Stewart<n7ws@yahoo.com> 
 wrote:
Hi Chris,

Thanks for checking this.  I can confirm, much to my chagrin, that your numbers 
are correct.

Everybody


Armed with this I just got back from walking the line from the corner pole to the west and then 
south to the pumping station.  I should note that with more attention I saw that the line to 
the west is three phase all the way, but does seem to carry a neutral.  One phase is feeding 
"my" line that runs to the north and another phase feeds the line running to the south.

With my Sony receiver tuned to 1705 kHz and the loopstick active, there was plenty 
of sensitivity, but little directivity, to hear the raucous noise under the pole 
feeding the pumping station.  Subject to changing my mind, I'm now 99% sure the 
source is there. Whether it's the power co-op or the water co-op at fault remains to 
be seen.

More to follow.



     On Thursday, March 7, 2024 at 08:19:16 AM MST, Chris L. 
Parker<parker601@earthlink.net>  wrote:
Hi Wes,

To answer your question, experience (been there, done that) and experimenting.
I pulled out the old Wavetek 3001 signal generator to confirm the antenna 
transition frequency yesterday.
Don's (WD8DSB) very effective flag antenna is now a kit on DXEngineering.
Specified usable for DF down to 1.8 MHz.
The flag will need a preamp for use with the Sony 7600GR (and blocking cap). 
They sell a preamp as well.
I built a much more "stealthy" 6-inch ARDF loop for my MW DF work. (QST, Sep 
2005, Dale Hunt, WB6BYU)
I have an unidentified 160 meter RFI source in a strip mall 1/4 mile away from 
me.
Noise conducts (not radiates) through the powerlines towards my residence. Very 
tricky to locate due long wavelength.
I suspect my RFI is HVAC, commercial refrigeration, or similar variable speed 
drive electric motor.

Hope this helps.
Chris
AF6PX

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