Sounds to me like its a not so simple case of more power line noise coupled
into the antenna at it increased height, which at its new height is also
closer to the height of the power line. But the comments about the large
difference in noise observed and also the contradiction to the square law
effect are interesting.

Maybe the question we should be pondering is NOT what the changes in the
antenna pattern are, but what the antenna pattern of the *power line* at the
observed freq is. These things are by nature antennas as well which also
exhibit directivity and gain (I'm cringing at the thought of future BPL
"dx"), but would probably be impossible to model since there are too many
unknowns.

So my 2 cent theory is that the original antenna location lies in a power
line noise pattern null (or no low angle) and at the new height it's now in
a lobe.

John



"Richard Clark" wrote in message
...
On Sun, 28 Nov 2004 06:47:45 -0600, Warren Bowery
wrote:
Reg - any increase in signals certainly did not increase enough to
overcome
the noise. Like I mentioned, the original configuration I is very quiet.
In fact, the noise level went from not registering on the meter at all at
the lower height to an S9+ when I raised the antenna.

Hi Warren,

Then it appears you upset the balance of the antenna (hard to believe
it was balanced before) such that common mode noise is finding its way
in.

It seems entirely unlikely that you achieved any more gain, nor more
highly resolved angular discrimination to now be focused on a source
of noise that has "always" been there.

The way I read your statements, it's as if you raised your antenna to
the equal horizon of a noise your antenna in its former position just
couldn't see. At HF and at those heights, this just isn't in the
cards. Signal intensity follows square law and for your noise to rise
from nothing to S-9 does not correspond to any dimensional change (or
if it does, there's your clue, but you are within inches of it now
where you were 10's of feet away formerly).

73's
Richard Clark, KB7QHC

On Sun, 28 Nov 2004 12:15:40 -0500, "- XC -" wrote:

So my 2 cent theory is that the original antenna location lies in a power
line noise pattern null (or no low angle) and at the new height it's now in
a lobe.

Hi John,

The simple wavelength mechanics of that negate the premise. For any
structure, much less a power line, to exhibit a null due to a dipolar
distribution; then that would have to arise from certain constraints.
Chief among them is isolation from ground by a significant portion of
one wavelength, in this power line case 5000000 meters.

However, the noise is not 60Hz. In the case of the actual frequency
of the interference, it is equally unlikely to be emanating from the
power lines - from the 60 Hz generation end. It would necessarily be
emanating from a load that is using the line as an antenna (although,
not purposely except in your nightmare of BPL).

In this case of higher frequency nuisance, the same powerlines would
present an enormously long structure (unless the noise were snubbed at
the nearest isolation transformer). that would create a huge number of
lobes. And still, it is unlikely that any null to peak of those lobes
would match the characteristic of no noise to S-9 variation. As such,
the odds are on square-law ruled proximity. Where in quieter times
past the noise was 10's of feet away, with change that noise got
within inches. That, or the description of noise levels has been
exaggerated.

A noise survey should be performed with a simple handheld transistor
SW receiver. Walk around and listen. If push comes to shove, then
tie a string to the receiver, turn up the volume and hoist it up.
More can be determined by this than all the arm-chair prognosis.

73's
Richard Clark, KB7QHC

Richard:

Don't forget the harmonics that may be caused and radiated by the power
lines...

Just a thought.

-SSB

Richard Clark wrote:
On Sun, 28 Nov 2004 12:15:40 -0500, "- XC -" wrote:


So my 2 cent theory is that the original antenna location lies in a power
line noise pattern null (or no low angle) and at the new height it's now in
a lobe.


Hi John,

The simple wavelength mechanics of that negate the premise. For any
structure, much less a power line, to exhibit a null due to a dipolar
distribution; then that would have to arise from certain constraints.
Chief among them is isolation from ground by a significant portion of
one wavelength, in this power line case 5000000 meters.

However, the noise is not 60Hz. In the case of the actual frequency
of the interference, it is equally unlikely to be emanating from the
power lines - from the 60 Hz generation end. It would necessarily be
emanating from a load that is using the line as an antenna (although,
not purposely except in your nightmare of BPL).

In this case of higher frequency nuisance, the same powerlines would
present an enormously long structure (unless the noise were snubbed at
the nearest isolation transformer). that would create a huge number of
lobes. And still, it is unlikely that any null to peak of those lobes
would match the characteristic of no noise to S-9 variation. As such,
the odds are on square-law ruled proximity. Where in quieter times
past the noise was 10's of feet away, with change that noise got
within inches. That, or the description of noise levels has been
exaggerated.

A noise survey should be performed with a simple handheld transistor
SW receiver. Walk around and listen. If push comes to shove, then
tie a string to the receiver, turn up the volume and hoist it up.
More can be determined by this than all the arm-chair prognosis.

73's
Richard Clark, KB7QHC