[RFI] Working with Utilities

[Jim Brown]

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.