Richard Clark wrote:
On Tue, 05 May 2009 17:10:16 +0200, noname wrote:

On Mon, 04 May 2009, Richard Clark wrote:
A very good description of your set-up. You are already
grounded through a the haphazard path of your AC outlet
- if you chose to use three prong connections, if your outlet
is in fact grounded, if your equipment actually has a safety
ground to chassis. A lot of "ifs," hence my use of "haphazard."

Okay, I have checked each of those. The house was recently inspected
ensure compliance with recent building code requirements, with the
outlets and overall grounding system checked for proper wiring at that
time. The house wiring exceeded current building requirements, which I
was indeed happy to hear.

Hi Steve,

So, in fact your three prong plugs find their way to the panel ground.
Can YOU find that ground?

The radio uses a three-prong cord (a requirement here), with the
chassis apparently connected at several points to the ground of that.
It appears the antenna shield side of the connector is also bolted
directly to that chassis.

So, by this explicit statement, your "balanced" antenna has been
unbalanced at the rig (which only further enforces the unbalance by
virtue of the coax connection).

By deliberately adding a ground wire going to an ad-hoc
ground rod, you can easily introduce problems. (snip)

So you recommend no additional grounding?

This is a loaded question because there are TWO grounds which
discussion often gets mixed. They may both go to the same point of
zero potential, but their paths are what distinguish them. The TWO
grounds are safety ground and RF ground. Any wire that is
significantly long at a wavelength of your operation, will qualify
more as a radiator than it will as a ground wire.

Consider you are sitting at your transmitter, it has a dedicated newly
applied ground wire that runs the shortest distance to what you think
of as ground. Maybe that is all of 10 feet. You are operating on
10M. Ground is a quarterwave away. That puts your equipment at the
high potential end of a wire with zero potential at ground. How
grounded does that sound?

Worse than that. You've basically made a big loop antenna: greenwire
ground to panel, panel to ground rod, ground rod to rig.





The solution there is to add an artificial ground tuner to move that
potential away from you (this would be an attempt to "balance" the
distribution so that your equipment sits at an artificially imposed
neutral - ground of another mother).

Or, easier.. put a choke around the feedline where it comes into the
shack, so that there's no appreciable RF current through the chassis and
green-wire ground.




Thing is, as I said, you already have a ground connection. The safety
ground is a necessity unless you are very practiced in the art of
isolation. You can add another path, and, again, that path may be a
different length to the one you already have. Given that situation,
you may find one path now spilling current into the new one - as
dependant upon the wavelength of operation and the physical path
lengths. When this spilling from one path into the other occurs,
strange things happen compared to if you hadn't added that new path.


Exactly.. one DC/Line frequency path is all that's needed for safety.