"Rick" wrote in
:

Owen,
You bring up some very interesting points, precisely what I was asking
for in my original post.
Thank you very much for your assistance.
My theory right now is this:

I have found 2 noisy poles using 440 MHz, both 1.2 miles from me. I
HOPED that they would solve my 80 meter problem, once repaired.
As I go lower in frequency, down to 10 meters using vertical whips, I
confirm that the noise can be heard farther away, as much as about 1/2
mile on 10 meters.

I am not surprised. The directivity of the 'antenna' varies with
frequency, as may be the power radiated.

Trial BPL emissions that I measured could be heard above the noise on 40m
in a mobile station more than 1km from the trial area. Remember that this
was an emission that its promoters (including the FCC) asserted would not
cause interference.

I am assuming that the 2 MHz component of the broadband noise is being
conducted on the lines with very little attenuation for the 1.2 miles
to my house where it is 20 over 9 on a Beverage parallel to the lines.

That antenna configuration maximises coupling to the currents flowing on
the power lines.

Using my loop at 2 MHz I am essentially unable to get any bearing
because the source is essentially a couple miles in length. ????????
And I can't get any significant distance away from the power lines.
(One place on my property is 200 yards from the lines but the loop
can't determine a null. Yet it does fine with locating BCB stations,
so I think it should be usable if the noise was a point source).

But you are not limited to taking bearings from on your own property.

I will say again, if you are close to the power lines, eg within say, a
quarter wave, the loop mutual coupling with the power lines will reduce
its effectiveness for obtaining a valid bearing.


Although the power lines act as a very long antenna, I have had no
difficulty locating BPL injection points using the loop nulls.
What frequency do you look at for BPL? upper HF (10-20 MHz, where it
looks more like a point source?)


If you stand under the power lines, you won't get a result, you need
to move
away from them, you should readily get a good set (ie reliable,
convenrgent) of cross bearings.

I can say that again!


I am failing at that so far, see above.


Sure you can look for interference at 70cm or at ultrasonic
frequencies... but that won't work unless the source is truly
wideband.

This statement puzzles me. Can you please explain more? Can it be
that the poles which clearly
show lots of noise at 440 are NOT the ones causing my problem at 80
meters? i.e. can there be defects which generate noise peaking at LF
and not detectable on 440?

It is not just a matter of whether a fault (eg a leaking bushing) creates
emission of constant power density from DC to daylight, the lines,
earthing system etc all introduce frequency effects on amplitude. You
could easily discover a relatively noise fault on 440 that is not the
root cause of high 1.8MHz emissions at your location.

My advice is that if you sense emissions at some secondary frequency,
always relate it back to the primary problem. It is OK if the power
company wants to locate faulty insulators with an ultasonic detector, or
a UHF detector, but when they have 'repaired' the fault, the valid test
of whether *your* problem is fixed is measurement or observation at the
frequency at which you suffered interference.

It is just a matter of logic.

For example, if you report a problem on 1.8MHz, and the power company
attends. They report that they found 3 faulty insulators and 1 case of
loose hardware using their ultrasonic detector and sledge hammer and
fixed them. Your problem must now be solved.

No, your problem is only solved when the interference at 1.8MHz has gone
away, it doesn't matter how many other faults they found and fixed while
investigating, until they fix the one(s) that cause your problem, the
problem is resolved.


The other thing is that if you make a complaint, demonstrate
emissions at 70cm, and they fix them at 70cm, what do you do if they
didn't solve your primary problem.

That would be my worst nightmare. That's why I am looking for a better
understanding as I asked above.


IMHO, better to measure the problem at the primary frequency, report
the real problem, not the cause, but the primary impact on yourself.

I did that, starting 11 months ago. I played dumb, just said here's
my problem.
The power company guy who has been trying to help me has a wideband
spectrum analyzer, and uses a 300 MHz-1GHz LP antenna, hand held. For
low frequencies just a pull-out whip. He prefers to use his hand held
ultrasonic device with headphones, probably because he has had good
success with it. He let me experience it once and it definitely can

Ok, they are all techniques for finding faulty equipment... but if they
don't measure the emissions at your place before and after, they have not
proven that the faults found contributed to the interference problem.

Is that hard to grasp?

hear a problem on a pole. So I'd say right now he has the best
capabilities at ultrasonic, and I do at UHF (with my 8 element Quagi
and sensitive receiver), and neither of us does at low HF.

Again, I earlier made the point that detectable noise is not necessarily
actionable. It would be unreasonable to require power line emissions to
be undetectable. In that environment, measurement of the emission level
either in absolute terms or relative to ambient noise (the degradation
caused, if you like) may be relevant to whether the case is actionable.

My experience with BPL particularly, and also with weak signal working is
that hams, by and large, don't have much interest in noise, and therefore
much knowledge of noise as it limits the communications channel.

An anecdote: A notable VHF weak signal operator reported "I am suffering
interference at S9 to 40 over S9 on 2m" led to my question given that he
has a high gain array with masthead preamp etc "what does S9 mean?". I
was told that his system was 'calibrated', he adjusts the transceiver
input attenuator so that the S meter reads zero on band noise.

In the jurisdiction, there is a standard that limits power line emission
field strength (specified in uV/m) from power lines, and if it could be
demonstrated that the emission exceeded that, there was no question, it
needed to be reduced, not eliminated, but reduced to comply with the
standard.

But, S9 mean't nothing in terms of the standard, it did not providing a
compelling case of non-compliance.

BTW, in this jurisdiction, if a leaky insulator also affects local
broadcast reception, a report along those lines is more likely to get
action.

Owen