To all who have commented on this problem.
Bill has presented a very good resume of one of the best ways to
proceed. I suspect that following his guidelines will produce results in
more than 90% of the cases.
I do not agree that "small" is any indication of the technical
expertise that is available. Many times a small organization will have
personnel that are multi-faceted with more expertise that some larger
companies.
However, the manner in which you present your problem will
largely dictate whether you receive an immediate response or not. I
agree that just saying that it is interfering with your hobby will get
you minimum response in most cases. If you can present a case of
broadcast interference (radio or especially TV), then you have a bunch of
neighbors who are most likely having interference problems with their
reception. That makes you a consumer group and not just a single radio
freak. Be a concerned consumer, expressing that you are also worried
about the integrity of the distribution system.
Be positive and offer your time to work with them. Many times
the smaller utilities just don't have enough personnel to dedicate
unlimited time to RF interference. Once you have the commitment from
them to work with you, anything you can do will help the process.
I first had HF electrical interference from local Coop lines in
1966/1967. I used my mobile HF radio and located some problems near my
home. I then went to the Coop office, asked to see the General Manager,
and told him my story. He made a two man crew available to me and
together we corrected the problems to my satisfaction.
The Manager was so impressed with my ability to pin point problem
poles that he contracted me on a temporary basis to survey the entire
system and locate all major interference sources. The project worked
well and we found many sources of noise that would have eventually caused
operational problems on the electric distribution system.
As fate would have it, in 1968 I went to work for the Coop as an
apprentice lineman. I am close to finishing 28 years with them and now
occupy the position of Supervisor of Technical Services. During these
intervening years I have addressed a multitude of RF interference
problems. I don't know if any of this will help, but I share a brief
overview of what I know with the intent that it will help someone
somewhere.
First, the issue of Public Utility Commissions. In the two
states where I work, New Mexico and Arizona, Cooperatives are under the
jurisdiction of the PUCs. If you are in a state where this is the case,
then I would suggest going to the PUC only after all other reasonable
attempts have been made to solve the problem.
As one commenter expressed, the utility's job is to prevent
outages. And many of the sources of electrical RF noise are associated
directly with connections on the primary voltage lines. Always suspect
locations where the primary conductors are double dead ended, and the
through connection is made by using jumpers with HOT LINE CLAMPS. Some
older varieties of these clamps do not have spring loaded clamping, and
can loosen over time with wind induced vibration. The noise is caused by
arcing in the contact, and the end result is heating and eventual burn
down of the conductor at that point. The same is true at any primary tap
from a main circuit. The HOT LINE CLAMP is used extensively for
connecting these circuit taps whether they are a single span or many mile
long. The same is true for transformer connections to the primary
conductor and other equipment such as capacitor banks and lightning
arresters. HOT LINE CLAMPS are always suspect.
Ungrounded metallic items such as crossarm braces and equipment
mounts (lightning arrester brackets)in close proximity to the pole ground
wire are common spark gap creators. Move the metallic item or reroute the
ground wire to create a larger gap. Also look for guy wires (which are
grounded) in close proximity to ungrounded hardware.
In the same category are the staples which hold the ground wire
in place. If the staples (and it only takes one) are loose (especially
the ones located within six feet or so of the primary conductors) they
will do a real good job of creating the noise producing arc. Staples
with a UV protected PVC insert in the mouth are available to use near the
top of poles. Even if the problem staples are repounded, vibration and
age wearing of the pole's surface will allow the same to happen again in
a few years. It is much better to pull out the old staples and repound
with new ones in new locations. And use the insulated staples if at all
possible.
With common distribution voltages (4kv to 25kv) insulators are
not normally a problem. However, in a few instances a pinhole will be
created by a lightning strike and there will be leakage to the metallic
pin holding the insulator.
Transformers are not a large percentage of the noise producers,
but they can occur especially if your utility uses transformers with tap
changers in the primary windings. Another variety is the CSP (Completely
Self Protected) transformer which will have a secondary voltage circuit
breaker. If a noise source is confirmed to a transformer pole location,
and all the other common causes have been checked, have the lineman lift
the hot line clamp of that transformers source for a few seconds. If the
transformer is the problem, the noise will go away.
The same is true of capacitors (used for Power Factor correction)
and lightning arresters. Small percentage of the noise sources, but
occasionally they will break down internally.
Look for trees that have not been properly trimmed. Some of
these will create noise only when wind is blowing a branch into a
conductor. Usually the branch will be burned off and you will be able to
see the blackened end.
Over the years I have used various types of receivers to locate
noise sources. I now use a CATV type Field Strength Meter (FSM) that
covers the VHF frequencies starting at TV channel 2 (54 mHz). I have
found that using the higher frequencies allows you to get within 2 or 3
poles of the noise source before you even start looking for the exact
location. At lower frequencies (BC and HF) the noise propagates long
distances and many times will be enhanced at certain poles or equipment
locations. At VHF this is not true. Also, the FSM has a calibrated
strength meter and switch selected attenuation pads built in. This
allows you to take exact readings over a very wide range of levels. Most
of the time I use a mag mount VHF omni antenna on a vehicle, but some
conditions have been better served by the use of a hand held 3 element
directional.
And last but not least, I will personally speak via telephone
with the responsible persons at any Cooperative who would accept my offer
to help. But let the guys in the Carolinas get Fran behind them before
we approach that one.
Thanks for the bandwidth, and 73 de
---Milt Jensen @ ARS N5IA---
---Virden, NM Route Box 176---
---Duncan, AZ -- 85534---
---H: (505) 358-2105 W: (520) 359-2503---
---Reply to n5ia@juno.com---
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