If you have an imbalance current trying to find its way to ground,
it'll
take the path of least resistance (technically, impedance). If that
path
is the mains wiring, you have a lot of potential for RFI. If you can
convince some of that current to go elsewhere by "grounding" your
station, you're likely to cut down the RFI. But a better solution is to
get those feedline currents balanced so you won't have any imbalance or
"ground" current to deal with in the first place. It brings the added
benefit of putting the power into your antenna to be radiated rather
than being radiated from the conductors carrying the imbalance current.


Exactly. This is why I call the "grounding" method a bandaid.
I think the 2nd solution is the best route to go. And if you use
the 2nd solution, the length of the line, and the location or height
above ground will not matter. And no worrying about getting a
good rf ground, which is hard to do in many remote locations of
a building.
MK

MK,
The 'problem' wasn't completely on my end (neighbor's defective
devices), but a good grounding did help cure the a RFI. Is grounding
a 'sure thing' as a cure? Nope, but it certainly doesn't hurt if it's
at all possible, which isn't always a 'sure thing'.
Also used to use a fence around the place as a ground. Very BAD idea
since the fence was connected to the neighbor's fence too. Just 'took'
the RF closer to the neighbor, probably a 'sort' of direct connection to
his 'stuff'. Always a 'bad' idea? No, but something to think about.
'Doc

Reg, it would really be nice if you could come up with some new topics
to keep you entertained on those dull evenings. You brought that one up
just four months ago. Maybe you can keep a list of your favorites,
noting when you used each one the last time, and giving us a little
longer break between repetitions.

Reg Edwards wrote:
Roy!

Just a legitimate crude guess - perhaps biassed a little in the
opposite direction to the normal excessive bias.

If I remember correctly, you, your very good self, used Eznec to
demonstrate that even under the most adverse worst-case conditions you
could think of, power radiated from the feedline is only a fraction of
that radiated from the antenna.

Sorry, you don't remember correctly. I said on quite a number of
occasions (and you once even agreed) that you can't assign radiated
powers from different parts of an antenna system. It was actually kind
of sad -- you kept loudly demanding that I provide fractions of power
from the feedline and antenna, ignoring my statements that it couldn't
be apportioned that way, and some time later you said out of the blue
that it couldn't. And then you wrote a program that does just that. At
the end of this posting is a summary of your contradictory statements
which I originally posted here on Sept. 1.

I did find with EZNEC that the current on a feedline could be very much
larger than your program predicts.

. . . . . and the equipment being interfered with is in the
near-field of the antenna just as it is in the near-field of the
feedline. That, for most people, includes your next-door neighbors.
Especially if your next-door neighbors happen to be within the antenna
beam.

Depends on the orientation of your antenna and the size of your lot. My
antennas are some distance from the house, but the feedlines come right
inside.

----- My posting on this group on 9-1-2005 -----

If anyone besides me is having trouble keeping track of what Reg is
trying to say, maybe the following recent quotes will help. That is,
they'll help you understand why you're having trouble keeping track.

For what it's worth, I agree with the first quotation of 8/31. But
apparently Reg doesn't, even though he said it.

Roy Lewallen, W7EL

8/30:

Perhaps somebody might be prepared to state the power actually
radiated from feedlines in watts. At least it may create the
impression you know what you are talking about.

8/30:

Roy, do everybody a favour, by stating, numerically, how much power is
radiated from feedlines. Then somebody might have some confidence in
what you are bafflegabbing about.

8/31:

Any current which finds its way on to (3), which ought to flow in the
antenna, will result in the coax participating in the radiation
pattern of the whole antenna structure.

BUT IT IS A SILLY QUESTION TO ASK HOW MANY WATTS ARE RADIATED FROM THE
FEEDLINE.

OR, CONVERSELY, HOW MANY MICROWATTS ARE PICKED UP BY THE FEEDLINE ON
RECEIVE.

The feedline cannot be treated in isolation as if it behaves
independently of the antenna. For starters, the radiation resistances
of the feedline and antenna do not add arithmetically. They interact
with each other.

8/31:

If you erect a 10 meter 1/2-wave dipole and center-feed it with a 50
feet length of coax, and then transmit on 1.9 MHz, 99.9 percent of
available power will be radiated from the feedline and only 0.1
percent from the antenna itself.

http://www.smeter.net/feeding/feedpowr.php:

Centre-Fed Dipole - Radiation from Coaxial Feedline
Author: R.J.Edwards G4FGQ © 25th March 2003

Program Notes
.. . .
With no loss in accuracy, to simplify the model, the transmitter is
located at the dipole centre and the coaxial line is replaced by a
single conductor of the same diameter as the coaxial braid. There are 3
radiating elements. Radiation resistance, input impedance, and input
current of each element is calculated. Finally, the percent of total
power radiated by each of the three elements is calculated.

---------------------

Roy Lewallen, W7EL

ORIGINAL MESSAGE:

On Mon, 02 Jan 2006 23:19:15 -0800, Roy Lewallen
wrote:

But a better solution is to
get those feedline currents balanced so you won't have any imbalance or
"ground" current to deal with in the first place.


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Not only that, but whenever the neighbor plugs in a different
appliance, uses an extension cord or otherwise rearranges his AC
mains, your problem may be right back.

73, Bill W6WRT