Lots of excellent advice here about tracking down impulse noise, which
is what power line noise is. But it's less likely to be useful for
electronically generated noise, like switch-mode power supplies and
power control electronics, like controllers for variable speed motors,
nor for systems using microprocessors.
One inportant correction though -- "Polarity" is the positive or
negative-going sense of a signal, like going through an inverting gain
stage, or turning a pair wires over. What you're talking about here is
"Polarization." And you're right that it can be very important.
73, Jim K9YC
On 9/11/2021 9:43 AM, AA5CT via RFI wrote:
re: "That is half of the equation."
Beg your pardon here Ed Hare.
I don't know what you read into my reply Ed, but, that is not my experience with
this technique! Note I said UHF, not VHF and with a handheld Yagi antenna. I
have
even tried a 900 MHz Yagi to do the DF, but the amount of signal there is
notably
down from that at UHF (450 MHz).
Ed, it becomes QUITE apparent when using this UHF DF technique in the field
WHERE the source is, where the RF is coming from, and its definitely NOT from
'all along the line' as you seem to indicate. AND its easy to note if it comes
from
a house or from hardware up on a pole.
There is even a POLARITY associated with these noise sources - orienting the
Yagi vertically and horizontally results in changes in signal strength.
I don't know that you've ever tried this UHF AM rcvr plus beam technique in the
field, Ed, but it becomes quite apparent when actually using this technique just
where the noise, where the signal originates.
Again, walk around, sniff the noise source with your HAND-HELD UHF beam
and note WHERE the signal is strongest. You'll find it. Note: Use AM rx mode
on the receiver, and you'll hear the characteristic 60/120 Hz (base rep rate)
'buzz' of the arcing source.
This technique (USED to find the individual offending pole) has not failed me
yet.
And, AGAIN, I use other techniques (LIKE HF DF) to locate down to the vicinity
of the offending pole.
THIS response, this e-mail, was directed to the original poster in this thread
to
help ID and note an arcing set of BELL insulators, that was all. But Ed took it
in a more general direction.
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