Earlier this year I tracked down RFI on 160 and 80 meters to a power pole
that's 0.5 miles from my house. A Duke Energy engineer met me at the
suspect pole one month ago and quickly identified the problem as a bad
lightning arrester on the pole using his ultrasonic parabolic dish
receiver, and due to the Coronavirus we had to practice safe distancing.
The interesting point about this case was that the RFI not only stopped
when it was wet, but also stopped when it was warm. I noticed the RFI
would be totally absent on warm days, but would reappear when it was cold.
I then started manually logging the outdoor temperature versus what percent
of time the RFI was present. It quickly became obvious that the RFI was on
100% of the time when the temperature was below 45 degrees but as the
temperature increased above 45 degrees the RFI on time would start
decreasing. As an example at 48 degrees F it would appear in bursts with
an on time of about 50% (during a 1 minute period it would be on about 50%
of the time). At 50 degrees it would appear in bursts with an on time of
10%, and at 54 degrees F it was almost gone (1 or 2 one second bursts each
minute). Above 55 degrees the RFI completely stopped.
Understanding the temperature dependence was very important in my
coordination efforts with the utility company (Duke Energy). The engineer
from Duke first scheduled a day and time when it was going to be above 70
degrees, and I asked him to reschedule for the following day before 10 am
since it would be below 45 degrees and that would be our best chance to
catch the pole generating RFI. He agreed to reschedule, and sure enough
the pole was generating RFI when we met, and he quickly identified a bad
lightning arrester using his ultrasonic parabolic dish.
Here is the link to an unlisted recording I made that documented my RFI,
and I made this video so the Duke engineer could understand my RFI
complaint before we met in person at the pole.
https://www.youtube.com/watch?v=ATMkvS1MdgQ
Just FYI, and 73.
Don (wd8dsb)
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