why not just a rusty coat hanger and some bailing wire? grin

John

"Dave" wrote in message
...
in other words i think he is trying to make a J pole into a coaxial
arrangement where the short part of the J wraps all the way around the
pole.
personally it sounds like a lot of work to get rid of some small
assymetry
caused by the gamma rod. the easier solution is a plain vertical with
a
tuner to make the transmitter happy.

"John Smith" wrote in message
...
... err, not to be confused with a "dipole beam", which is better
referred to as a "two element beam" to remove all confusion... grin

Warmest regards,
John

"John Smith" wrote in message
...
Not that I am aware of, only thing is there is no where to "hang"
that
T-Match--well, the mast I mentioned... and the fact the monopole is
absent the bottom half of a dipole element... this is especially
notable if the bottom end of the monopole is sitting on the
ground...
that tends to remove all confusion... grin

Warmest regards,
John
"Cecil Moore" wrote in message
...
John Smith wrote:
I should have pointed out, a T-Match requires a dipole, a few
seem
to miss I had previously noted this is a monopole in question...

Is there any difference in a 1/2WL monopole element and a
1/2WL dipole element sans the T-Match? I can't think of any.
--
73, Cecil http://www.qsl.net/w5dxp

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"Tom Ring" wrote in message
.. .
Dale Parfitt wrote:

"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



Dale

Was that you I worked while mobile on 6 yesterday or the day before?
Sounds like the call I remember.

tom
K0TAR

Hi Tom,
I knew the band was open because of 88-108 stations booming in, but my rotor
and remote antenna switch wires to the tower are temporarily disconnected
while we build a 180 ton rock wall behind the house. I'll be back on this
weekend.

Dale W4OP

John Smith wrote:

I should have pointed out, a T-Match requires a dipole, a few seem to
miss I had previously noted this is a monopole in question... a T-Match
would unbalance the RF RADIATION PATTERN of a dipole in the same way a
gamma does a monopole, there would be no gain from using a T-Match in
place of a gamma, EVEN if it could be done here...
I suppose you might be able to mount the bottom of T-Match on the mast
holding the monopole--but then, that is another experiment for another
day...

Warmest regards,
John

I've been thinking about a delta type match as a way to couple to a 1/2
wave radiator. Might be interesting.

ac6xg

"John Smith" wrote in message
...

Dale:

Yes, someone injected a T-Match in here, but no real interest in a
T-Match...

Warmest regards,
John

"Dale Parfitt" wrote in message
news:ODOne.7695$vK5.2782@trnddc03...

"Dave Platt" wrote in message
...

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?


Check out any of the antenna handbooks for a Tee match. The driven
element
is insulated from the boom and split in the middle. Each side of the
Tee
taps out on the D.E. at a point yielding a 200 Ohm balanced feed. A
4:1
coaxial balun is used to transform the 200 Ohms balanced down to 50
Ohms
unbalanced.

Dale W4OP

might just work, if the total element length is 1 wave! and in a dipole
configuration...

Warmest regards,
John

"Jim Kelley" wrote in message
...


John Smith wrote:

I should have pointed out, a T-Match requires a dipole, a few seem to
miss I had previously noted this is a monopole in question... a
T-Match would unbalance the RF RADIATION PATTERN of a dipole in the
same way a gamma does a monopole, there would be no gain from using a
T-Match in place of a gamma, EVEN if it could be done here...
I suppose you might be able to mount the bottom of T-Match on the
mast holding the monopole--but then, that is another experiment for
another day...

Warmest regards,
John

I've been thinking about a delta type match as a way to couple to a
1/2 wave radiator. Might be interesting.

ac6xg

"John Smith" wrote in message
...

Dale:

Yes, someone injected a T-Match in here, but no real interest in a
T-Match...

Warmest regards,
John

"Dale Parfitt" wrote in message
news:ODOne.7695$vK5.2782@trnddc03...

"Dave Platt" wrote in message
...

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?


Check out any of the antenna handbooks for a Tee match. The driven
element
is insulated from the boom and split in the middle. Each side of the
Tee
taps out on the D.E. at a point yielding a 200 Ohm balanced feed. A
4:1
coaxial balun is used to transform the 200 Ohms balanced down to 50
Ohms
unbalanced.

Dale W4OP

.... however, would still distort radiation pattern due to the match on
one side... perfect symmetry prompted me to begin this line of thought
and tweaking the equations...

Warmest regards,
John
"John Smith" wrote in message
...
might just work, if the total element length is 1 wave! and in a
dipole configuration...

Warmest regards,
John

"Jim Kelley" wrote in message
...


John Smith wrote:

I should have pointed out, a T-Match requires a dipole, a few seem
to miss I had previously noted this is a monopole in question... a
T-Match would unbalance the RF RADIATION PATTERN of a dipole in the
same way a gamma does a monopole, there would be no gain from using
a T-Match in place of a gamma, EVEN if it could be done here...
I suppose you might be able to mount the bottom of T-Match on the
mast holding the monopole--but then, that is another experiment for
another day...

Warmest regards,
John

I've been thinking about a delta type match as a way to couple to a
1/2 wave radiator. Might be interesting.

ac6xg

"John Smith" wrote in message
...

Dale:

Yes, someone injected a T-Match in here, but no real interest in a
T-Match...

Warmest regards,
John

"Dale Parfitt" wrote in message
news:ODOne.7695$vK5.2782@trnddc03...

"Dave Platt" wrote in message
...

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?


Check out any of the antenna handbooks for a Tee match. The driven
element
is insulated from the boom and split in the middle. Each side of
the Tee
taps out on the D.E. at a point yielding a 200 Ohm balanced feed. A
4:1
coaxial balun is used to transform the 200 Ohms balanced down to 50
Ohms
unbalanced.

Dale W4OP

John Smith wrote:

might just work, if the total element length is 1 wave! and in a dipole
configuration...

You're thinking too far outside the box. Reel it back in a smidge. :-)

ac6xg

Jim:

Well, I have found terminology interesting. And, depends on whose you
use, there is ARRL of course, then there are a bunch of in-house tech
docs from industry.

Take what I have been accustomed to calling a 1/2 wave monopole--for
example: on 10 meters, it is about a 16 foot metal length and end fed.
An EFHWA. Most frequently fed through an L-Match or 1/4 wave matching
section--sometimes uniquely though an unun.

However, if you attempt to feed it in the middle, it suddenly becomes a
dipole, the equiv of two 8 ft-1/4 wave monopoles connected at there
bases, and would take a unique feed I am not familiar with, as each 1/4
wave section would need be fed out of phase--and this would be difficult
with the impedance so close to the feedline (coax in this case) and
having the 1/4 monopoles connected (notice, I didn't say impossible!
grin.)

Spilt the 1/2 monopole and center feed it and it becomes two 1/4 wave
monopoles (commonly referred to as a 1/2 wave dipole) and can be center
fed with convention means quite easily, as a dipole (indeed, many feed
them directly from coax--the more picky through a isolation balun or 1/4
wave section.)

However, two 1/2 monopoles, connected at their bases (actually a 1 wave
length single element) begins to accept center feeding with quite
conventional means (ant feed point is high impedance), although in ARRL
literature this would be referred to as 1 wave dipole, still it could be
modeled as two 1/2 wave monopoles being fed out of phase.

All I am concentrating on is the EFHWA (and, if setup right requires no
counterpoise), and various means of feeding it, modifications and
experiments...

Warmest regards,
John
"Jim Kelley" wrote in message
...


John Smith wrote:

might just work, if the total element length is 1 wave! and in a
dipole configuration...

You're thinking too far outside the box. Reel it back in a smidge.
:-)

ac6xg

I could be wrong, but here's what I was getting at. You should be able
to vary the feedpoint impedance, where ever the feedpoint happens to be
(in this case, the end), by varying the distance between the attachment
points of the two conductors of the feedline. The closer they are
together, naturally, the lower the impedance. It should be possible to
find a match in this way. Part B would be to keep the feedline from
trying to radiate.

ac6xg

John Smith wrote:

Jim:

Well, I have found terminology interesting. And, depends on whose you
use, there is ARRL of course, then there are a bunch of in-house tech
docs from industry.

Take what I have been accustomed to calling a 1/2 wave monopole--for
example: on 10 meters, it is about a 16 foot metal length and end fed.
An EFHWA. Most frequently fed through an L-Match or 1/4 wave matching
section--sometimes uniquely though an unun.

However, if you attempt to feed it in the middle, it suddenly becomes a
dipole, the equiv of two 8 ft-1/4 wave monopoles connected at there
bases, and would take a unique feed I am not familiar with, as each 1/4
wave section would need be fed out of phase--and this would be difficult
with the impedance so close to the feedline (coax in this case) and
having the 1/4 monopoles connected (notice, I didn't say impossible!
grin.)

Spilt the 1/2 monopole and center feed it and it becomes two 1/4 wave
monopoles (commonly referred to as a 1/2 wave dipole) and can be center
fed with convention means quite easily, as a dipole (indeed, many feed
them directly from coax--the more picky through a isolation balun or 1/4
wave section.)

However, two 1/2 monopoles, connected at their bases (actually a 1 wave
length single element) begins to accept center feeding with quite
conventional means (ant feed point is high impedance), although in ARRL
literature this would be referred to as 1 wave dipole, still it could be
modeled as two 1/2 wave monopoles being fed out of phase.

All I am concentrating on is the EFHWA (and, if setup right requires no
counterpoise), and various means of feeding it, modifications and
experiments...

Warmest regards,
John
"Jim Kelley" wrote in message
...


John Smith wrote:


might just work, if the total element length is 1 wave! and in a
dipole configuration...

You're thinking too far outside the box. Reel it back in a smidge.
:-)

ac6xg

Jim:

Could be... by the time I am done with the venerable half-wave-end-fed I
just might try it--I wasn't being picky, just explaining how I was
attacking the problem... I don't mind side excursions of thought--your
observations/suggestions are noted... thanks!

Warmest regards,
John
"Jim Kelley" wrote in message
...
I could be wrong, but here's what I was getting at. You should be able
to vary the feedpoint impedance, where ever the feedpoint happens to be
(in this case, the end), by varying the distance between the attachment
points of the two conductors of the feedline. The closer they are
together, naturally, the lower the impedance. It should be possible to
find a match in this way. Part B would be to keep the feedline from
trying to radiate.

ac6xg

John Smith wrote:

Jim:

Well, I have found terminology interesting. And, depends on whose
you use, there is ARRL of course, then there are a bunch of in-house
tech docs from industry.

Take what I have been accustomed to calling a 1/2 wave monopole--for
example: on 10 meters, it is about a 16 foot metal length and end
fed. An EFHWA. Most frequently fed through an L-Match or 1/4 wave
matching section--sometimes uniquely though an unun.

However, if you attempt to feed it in the middle, it suddenly becomes
a dipole, the equiv of two 8 ft-1/4 wave monopoles connected at there
bases, and would take a unique feed I am not familiar with, as each
1/4 wave section would need be fed out of phase--and this would be
difficult with the impedance so close to the feedline (coax in this
case) and having the 1/4 monopoles connected (notice, I didn't say
impossible! grin.)

Spilt the 1/2 monopole and center feed it and it becomes two 1/4 wave
monopoles (commonly referred to as a 1/2 wave dipole) and can be
center fed with convention means quite easily, as a dipole (indeed,
many feed them directly from coax--the more picky through a isolation
balun or 1/4 wave section.)

However, two 1/2 monopoles, connected at their bases (actually a 1
wave length single element) begins to accept center feeding with
quite conventional means (ant feed point is high impedance), although
in ARRL literature this would be referred to as 1 wave dipole, still
it could be modeled as two 1/2 wave monopoles being fed out of phase.

All I am concentrating on is the EFHWA (and, if setup right requires
no counterpoise), and various means of feeding it, modifications and
experiments...

Warmest regards,
John
"Jim Kelley" wrote in message
...


John Smith wrote:


might just work, if the total element length is 1 wave! and in a
dipole configuration...

You're thinking too far outside the box. Reel it back in a smidge.
:-)

ac6xg