[RFI] Power Line Noise Specific to 15 meters

[Michael Carter]

Thanks, Ed - those are good, notable exceptions
to the general trend of rain/condensation
shorting out the arc path/gap.  We have some
transformer primary bushings equipped with squirrel
guards, but they appear to have closed loops
rather than sharp prongs.  I have not observed
any RFI at 135 MHz around those transformers
in my neighborhood.

73,
Mike, K8CN
________________________________
From: EDWARDS, EDDIE J <eedwards at oppd.com>
Sent: Monday, October 4, 2021 10:01 AM
To: Michael Carter <Mike.Carter at unh.edu>; Pete Smith N4ZR <pete.n4zr at gmail.com>; RFI List <rfi at contesting.com>
Subject: RE: [RFI] Power Line Noise Specific to 15 meters

CAUTION: This email originated from outside of the University System. Do not click links or open attachments unless you recognize the sender and know the content is safe.


Mike,

You're statement that it's not likely is correct most the time (99.9%), but there are rare occasions when the hardware configuration doesn't follow the expected weather changes.

Had one case with a full metal cross arm where the RFI source did not go away when it rained.  These aren't used much if ever anymore by my utility as the sparking can also damage the wood pole.

Another RFI case some years ago was in my neighborhood that started up when it rained which turned out to be a squirrel guard on top of a transformer.  Found it with a new UE Systems ultrasonic back then.  The guard had metal prongs sticking out in all directions 360 degrees.  It sounded like a Jacob's Ladder when the rain initially started, and finally was on 100% in heavier rains.  When rain stopped the noise stopped as it dried out.  My utility stopped using this style guard based on my complaint.

73, de ed -K0iL

-----Original Message-----
From: RFI On Behalf Of Michael Carter

One more tip: if the RFI doesn't abate when it's raining, it is likely not an external power line arc source.  My local power line RFI goes away whenever we have a damp morning or a good steady rain.

73,
Mike, K8CN