Amen, Scott. A few years ago a whopping case of RFI at my house was
traced to one of two bolts mounting a lightning arrester on a pole. A
woodpecker had undermined one of the bolts, causing it to get loose, and
the strong field close to the 7.5 KV feed resulted in arcing between the
bolt and the bracket. One of the power guys told me that they had
switched to 1-bolt brackets for precisely this reason.
73, Pete N4ZR
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On 5/24/2020 2:45 PM, K9MA wrote:
It doesn’t have to be something that serious: two pieces of poorly bonded hardware anywhere
near a high voltage line will do it, especially if it’s within a few hundred meters of your
antenna. They don’t have to be directly connected to the line.
73,
Scott K9MA
----------
Scott Ellington
--- via iPad
On May 24, 2020, at 12:04 PM, Gary Johnson <gwj@wb9jps.com> wrote:
From: K9MA <k9ma@sdellington.us <mailto:k9ma@sdellington.us>>
To: rfi@contesting.com <mailto:rfi@contesting.com>
The clincher, in this case, is that the source goes silent when it is
wet, returns when it dries out.
We had persistent power line noise at N6RO for two years, and indeed it went silent
whenever it rained. Eventually the PG&E guy came out and precisely located it
(he was a ham, as it turned out). Root cause: A cracked insulator on a 13 kV line.
Rain would apparently suppress the corona discharge. No issues after the equipment
was replaced.
The character of the noise was a broad-banded and erratic sizzle, on all the low
bands. Mostly looked like white noise on the waterfall. In contrast, the noise caused
by my neighbor’s infamous LED lights, which have no filtering on the AC line
side of their switchmode converters, was a powerful 120 Hz harmonic buzz from dc to
daylight.
Gary NA6O
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