Dave:

Yes, the very bottom of the monopole with a concentric "gamma tube"
would be at ground level (NOT the BOTTOM of the "gamma tube", the top of
the "gamma tube" would be connected to DE with a shorting disk or
shorting strap and would be some distance up the DE, the bottom of the
"gamma tube" would connect to a series cap to tune out Jx of the "gamma
tube", and then to the center conductor of the coax.) and coax shield is
placed at the level of the bottom of the DE monopole...

Warmest regards,
John

"Dave" wrote in message
...
if you do a T match like telrex used on their monobanders there is no
favored side, the two T arms were fed with a 1/2 wave phasing line and
required no capacitor so everything was at dc ground. very simple to
build
and definately balanced.

"John Smith" wrote in message
...
Dave:

The T-Match will still show a favor in signal launch because of the
imbalance of the gamma rods on one side, on a beam this could even be
manipulated to ones favor--not as likely on a monopole... just
looking
for a way to completely balance the field pattern...
I just thought someone had most likely done something like this
before... if I don't hear of anyone, will shove some various sized
drain, stove pipe, soldered cans, etc. over a 1/2 monopole in place
of
the gamma rod and check it out this weekend...

Warmest regards,
John

"Dave" wrote in message
...
why not a T match. simpler to build and adjust than a gamma,
completely dc
grounded, and balanced.

"John Smith" wrote in message
...
From working with the gamma match in real life--I have noticed it
favors
launching the signal from the side of the DE which has the gamma.

Now in playing with the gamma formulas, I wondered...
What if the gamma rod is replaced with a "gamma tube", same set up
as
the normal gamma, except the the rod is now a tube surrounding the
element which is being fed? Something of a "concentric match", I
am
guessing the formula to compute concentric line Zo would come into
play
here, or a near equiv... purpose would be to get rid of the
favored
increase in signal from the side containing the gamma...

I know someone is going to suggest EZNEC--however, I am not good
at
drawing a tube with it!!!!

Warmest regards,
John
--
Watching the cutting edge of yesterday replay--in virtual reality,
right
before my eyes--in real time!
Thirty year old technology--wasn't it amazing?