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?

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?

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?

John Smith wrote:
The T-Match will still show a favor in signal launch because of the
imbalance of the gamma rods on one side, ...

A T-match is balanced because it is right+left gamma
matches, i.e. gamma rods on both sides with two equal
series caps (or tube caps).
--
73, Cecil, http://www.qsl.net/w5dxp

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Cecil:

Sorry, didn't mean that sort "balance"--as in a balanced antenna... you
are right to make me be more specific...

....rather, I mean in the radiated rf field pattern of the antenna
itself--because the T-Match is only on one side of the driven
element--the radiation will not be completely circular (as in a
vertical)--and will begin formation of a stronger pattern in one
direction over all other directions on a compass, this is in reference
to a vertical monopole, but still would be in effect in a horizontal
version, in affecting a stronger pattern in one direction.... (and of
course, there is no such thing as a "perfect" pattern, just degrees of
more or less.)

Warmest regards,
John

"Cecil Moore" wrote in message
...
John Smith wrote:
The T-Match will still show a favor in signal launch because of the
imbalance of the gamma rods on one side, ...

A T-match is balanced because it is right+left gamma
matches, i.e. gamma rods on both sides with two equal
series caps (or tube caps).
--
73, Cecil, http://www.qsl.net/w5dxp

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but a vertical monopole about 1/4 wave long doesn't even need a matching
system in most cases... unless you are a real perfectionist. just what are
you trying to build here anyway?

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

Sorry, didn't mean that sort "balance"--as in a balanced antenna... you
are right to make me be more specific...

...rather, I mean in the radiated rf field pattern of the antenna
itself--because the T-Match is only on one side of the driven
element--the radiation will not be completely circular (as in a
vertical)--and will begin formation of a stronger pattern in one
direction over all other directions on a compass, this is in reference
to a vertical monopole, but still would be in effect in a horizontal
version, in affecting a stronger pattern in one direction.... (and of
course, there is no such thing as a "perfect" pattern, just degrees of
more or less.)

Warmest regards,
John

"Cecil Moore" wrote in message
...
John Smith wrote:
The T-Match will still show a favor in signal launch because of the
imbalance of the gamma rods on one side, ...

A T-match is balanced because it is right+left gamma
matches, i.e. gamma rods on both sides with two equal
series caps (or tube caps).
--
73, Cecil, http://www.qsl.net/w5dxp

----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet
News==----
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120,000+ Newsgroups
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=----

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?

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?

"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
How can a T match have show a bias- it is balanced. Virtually all the
serious EME arrays use this matching technique and show the major lobe dead
off the front.

Dale W4OP

In article tJLne.13595$Vm4.9195@trnddc01,
Dale Parfitt wrote:

How can a T match have show a bias- it is balanced. Virtually all the
serious EME arrays use this matching technique and show the major lobe dead
off the front.

Are they feeding directly off of the coax, or do they use a halfwave
(or other) balun between the coax and the T?

Seems to me that a T directly from coax could show some amount of
imbalance. The center-conductor current would have only one pathway
to feed (the T), while the shield current would have two (the other
side of the T, and back down the feedline). If the outside of the
feedline was an integral number of halfwaves down to the point at
which it's grounded, there might be enough current flow on the outside
of the feedline to disturb the balance and change the pattern somewhat.

Sticking a half-wave coax balun at the input of the T ought to resolve
this pretty well, no?

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
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