All I know is the crepe myrtle had overtaken the ~ lower 20' of the
pole. Some branches >1" in diameter had grown around the pole, the
branches flattening out as they touched the pole. Only thing at that
height it could be touching was the stapled ground as it was shy of the
CATV/Phone level. I never saw it touching the ground though as the
foliage was too thick.
ID'ed as 120hz, direction with 6m/2m beams, triangulated with 2m
portable, heard it with ultrasonic on a completely wind free night
matching noise pattern pointing at the crepe myrtle (~10' height), heard
nothing top half of the pole, noise was heard on one side of the pole.
Was getting s9+10db noise on 80m and all through the HF bands up through
2m. But doublet end was within ~20' of the pole. Crepe myrtle cut away
from the pole and the noise is completely gone. In fact some
intermittent I had been hearing in that direction is gone.
Pole is minimal hardware with 3x 7.2kv phase lines going across the top
and a street light. About 10-15 years ago they completely rebuilt the
pole with new power hardware, due to my complaints, and it has been
noise free since until a few days ago.
In fairness though, the noise was active for about 2 days solid but with
varying pattern before I tracked and has been gone now for about 1 day
so maybe not enough time to fully evaluate as a success. The
wind/weather has been very calm throughout this period. If it comes back
will report it here.
Years ago I had 2 similar issues here but with vines. One on the 3
phase, one on single phase. In each case they were removed and the noise
gone. Foliage here in the south is very moist and aggressive especially
this time of the year.
As for the crepe myrtle, you can eliminate that as a cause of your RFI
even if it were touching the primary. You'll get ultrasound and
audible noise but you will not get rf. Contrary to what many people
say about finding their sources as trees touching the line, I have
never had a tree arching to the wire creating RF noise. If the crepe
myrtle gets within a couple of feet of the primary turn it into your
utility and they'll take care of it.
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
|