I needed to hear it from somebody else, that's all.

I'm not quite balanced in the feed, as I'm using coax out to the
dipole feedpoint, but probably close enough.

tnx - Mark

On Sun, 27 Nov 2005 17:27:04 GMT, 'Doc wrote:

Mark,
Sounds like a 'balanced' antenna to me, why a
ground other than for electrical purposes (not RF)?
- 'Doc

Mark Sheffield wrote:
I'm not quite balanced in the feed, as I'm using coax out to the
dipole feedpoint, but probably close enough.

A W2DU choke would probably eliminate the need for
an RF ground and also be good engineering practice.
--
73, Cecil http://www.qsl.net/w5dxp

I have a 2nd floor shack too, and the antenna is a ground mounted vertical
(Butternut HF6V). I use a W2DU choke to connect my coax feedline to the
vertical and a 2nd W2DU choke between my Orion and Drake L-4B. Finally, I
found that the only way to prevent feedback on SSB was to NOT connect my
system to the #8 ground wire that runs out the window sill and down to a
ground rod.

"Cecil Moore" wrote in message
. com...
Mark Sheffield wrote:
I'm not quite balanced in the feed, as I'm using coax out to the
dipole feedpoint, but probably close enough.

A W2DU choke would probably eliminate the need for
an RF ground and also be good engineering practice.
--
73, Cecil http://www.qsl.net/w5dxp

John, N9JG wrote:
Finally, I
found that the only way to prevent feedback on SSB was to NOT connect my
system to the #8 ground wire that runs out the window sill and down to a
ground rod.

Yep, everyone should realize that a ground wire is N*1/4 wavelength
at certain frequencies, and at those frequencies, is an RF transformer
that locates the standing-wave voltage maximum points at the transmitter. (ouch!)
That's what artificial grounds do - change that *electrical* length
to N*1/2 wavelength. For anyone insisting on an RF ground for an upper
floor, an artificial ground is probably the way to go. I, myself, prefer
balanced antennas and feedlines.
--
73, Cecil http://www.qsl.net/w5dxp

Cecil Moore wrote:
Yep, everyone should realize that a ground wire is N*1/4 wavelength
at certain frequencies, and at those frequencies, is an RF transformer
that locates the standing-wave voltage maximum points at the transmitter. (ouch!)
That's what artificial grounds do - change that *electrical* length
to N*1/2 wavelength. For anyone insisting on an RF ground for an upper
floor, an artificial ground is probably the way to go. I, myself, prefer
balanced antennas and feedlines.
--
73, Cecil http://www.qsl.net/w5dxp

Cecil, Don't you mean that when a ground wire is N*1/4 wavelength at
a particular frequency it locates the voltage mininum (current maximum)
at the transmitter, and the voltage maximum well away from the
transmitter. Artifical grounds use a series LC circuit to try and tune
your ground wire to look like 1/4 wave. If they change the
*electrical* length to 1/2 wave then you would have a voltage maximum
at the transmitter (ouch!).
Gary N4AST

wrote:
Cecil, Don't you mean that when a ground wire is N*1/4 wavelength at
a particular frequency it locates the voltage mininum (current maximum)
at the transmitter, and the voltage maximum well away from the
transmitter.

Nope, Mother Earth dictates the boundary conditions. A well-designed
ground system positions the current maximum point at the ground system,
i.e. minimum impedance to ground.

The voltage maximum point would, therefore, be located at the transmitter,
not a desirable condition. Of course, if you are not actually connected/
coupled to Mother Earth, your milage may vary.
--
73, Cecil http://www.qsl.net/w5dxp

Cecil Moore wrote:
wrote:
Cecil, Don't you mean that when a ground wire is N*1/4 wavelength at
a particular frequency it locates the voltage mininum (current maximum)
at the transmitter, and the voltage maximum well away from the
transmitter.

Nope, Mother Earth dictates the boundary conditions. A well-designed
ground system positions the current maximum point at the ground system,
i.e. minimum impedance to ground.

The voltage maximum point would, therefore, be located at the transmitter,
not a desirable condition. Of course, if you are not actually connected/
coupled to Mother Earth, your milage may vary.
--
73, Cecil http://www.qsl.net/w5dxp

I thought we were talking about 2nd floor, not well designed ground
systems, with the ground NOT connected to earth. But it is the best
you can do. That is where an artifical ground can help by locating
the voltage minimum at the transmitter.
Gary N4AST

Cecil Moore wrote:

John, N9JG wrote:
Finally, I
found that the only way to prevent feedback on SSB was to NOT connect my
system to the #8 ground wire that runs out the window sill and down to a
ground rod.

Yep, everyone should realize that a ground wire is N*1/4 wavelength
at certain frequencies, and at those frequencies, is an RF transformer
that locates the standing-wave voltage maximum points at the transmitter. (ouch!)
That's what artificial grounds do - change that *electrical* length
to N*1/2 wavelength. For anyone insisting on an RF ground for an upper
floor, an artificial ground is probably the way to go. I, myself, prefer
balanced antennas and feedlines.
--
73, Cecil http://www.qsl.net/w5dxp

Why not run two ground wires in parallel -- one twice as long as the
other? When one is Hi-Z the other will be Lo-Z and vice versa.

Irv VE6BP
--
--------------------------------------
Diagnosed Type II Diabetes March 5 2001
Beating it with diet and exercise!
297/215/210 (to be revised lower)
58"/43"(!)/44" (already lower too!)
--------------------------------------
Visit my HomePage at http://members.shaw.ca/finkirv/index.html
Visit my Baby Sofia website at http://members.shaw.ca/finkirv4/index.htm
Visit my OLDTIMERS website at http://members.shaw.ca/finkirv5/index.htm
--------------------
Irv Finkleman,
Grampa/Ex-Navy/Old Fart/Ham Radio VE6BP
Calgary, Alberta, Canada

Irv Finkleman wrote:
Why not run two ground wires in parallel -- one twice as long as the
other? When one is Hi-Z the other will be Lo-Z and vice versa.

That will help on some frequencies but it is akin to trying to
erect a 1/2WL fan dipole for all frequencies - can't be done. Sooner
or later, you will run into a frequency where length #1 is N*1/4WL
and length #2 is (N+1)1/4WL. "It's not nice to fool Mother Nature."
--
73, Cecil http://www.qsl.net/w5dxp

Cecil Moore wrote:

Irv Finkleman wrote:
Why not run two ground wires in parallel -- one twice as long as the
other? When one is Hi-Z the other will be Lo-Z and vice versa.

That will help on some frequencies but it is akin to trying to
erect a 1/2WL fan dipole for all frequencies - can't be done. Sooner
or later, you will run into a frequency where length #1 is N*1/4WL
and length #2 is (N+1)1/4WL. "It's not nice to fool Mother Nature."
--
73, Cecil http://www.qsl.net/w5dxp

OK then, I'll use 3 wires and take my chances! :-)

Irv
--
--------------------------------------
Diagnosed Type II Diabetes March 5 2001
Beating it with diet and exercise!
297/215/210 (to be revised lower)
58"/43"(!)/44" (already lower too!)
--------------------------------------
Visit my HomePage at http://members.shaw.ca/finkirv/index.html
Visit my Baby Sofia website at http://members.shaw.ca/finkirv4/index.htm
Visit my OLDTIMERS website at http://members.shaw.ca/finkirv5/index.htm
--------------------
Irv Finkleman,
Grampa/Ex-Navy/Old Fart/Ham Radio VE6BP
Calgary, Alberta, Canada