Topband: Finding powerline noise

Milt Jensen, N5IA n5ia@zia-connection.com
Tue, 10 Dec 2002 10:30:24 -0500


Ford,

If I might.  In my 30+ years of distribution power line experience I have
seen/found very few RF noise problems cuased by "leaking" primary voltage
conductors.

At least in my world and environment of the desert southwest USA, a high
percentage of sources of RF noise, "arcing", is caused by induced voltages
in ungrounded hardware that is in close proximity to grounded hardware or
ground wires.

The systems that I am familiar with are "Y" configured, and therefore have a
system, grounded neutral, conductor.  All return currents are via the
neutral with the exception of cases where the system neutral has failed
(broken, down on the ground, etc).
Delta configured systems operate with return current in the phase conductors
only.

In a "Y" system, the pole grounds are simply a parallel path of somewhat
higher resistance.  Current does not normally flow in them except during
faulted conditions, broken neutrals and lightning strikes.

I know of NO pole which will carry current as you suggest, given normal
distribution voltages.  Even at 25kV, 99+% of the time in our environment, a
primary conductor can rest on a crossarm and not be faulted to ground.  It
will not cause RF interference.

The receiver detection methods previously posted on this reflector and
others are tried and true methods of finding the source pole of RF
interference.  As with any other procedure, experience is the best help.
Knowing what you are hearing (what type of arc creates what type of noise)
really helps.  Knowing pole hardware and construction techniques (what to
look for on top of the pole) is 2nd best pool of knowledge.

Good luck to all.  73 de Milt, N5IA