In some situations it is better to have a 'shortened' antenna than the
absolute last tiniest fraction of a db. I realize a cap hat can
reduce the size of a vertical with reasonably low loss, I am wondering
if it would do as well with the J-Pole?

For example, a quarter wave matching network for the J-Pole would be
whatever works best, be it original design or some form of balun, but
the 1/2 wave vertical might be reduced in size by forming a capacity
hat above it.

How well would that work for shortening a J-Pole? would it be better
to use a shortened 1/2 wave dipole or would the J-Pole design be
better?

Buck

--
73 for now
Buck
N4PGW

Becareful Buck!!! It is catching, you are starting to think like me!

Regards

--
Hay, if'n ya'll cun't konstructivly partecipete in this har disscusion, haw
aboot speel-checkin it fer me?


"Buck" wrote in message
...
In some situations it is better to have a 'shortened' antenna than the
absolute last tiniest fraction of a db. I realize a cap hat can
reduce the size of a vertical with reasonably low loss, I am wondering
if it would do as well with the J-Pole?

For example, a quarter wave matching network for the J-Pole would be
whatever works best, be it original design or some form of balun, but
the 1/2 wave vertical might be reduced in size by forming a capacity
hat above it.

How well would that work for shortening a J-Pole? would it be better
to use a shortened 1/2 wave dipole or would the J-Pole design be
better?

Buck

--
73 for now
Buck
N4PGW

On Tue, 29 Mar 2005 13:41:50 -0800, "John Smith"
wrote:

Becareful Buck!!! It is catching, you are starting to think like me!

Regards


hmmm, maybe I should killfile you for being contagious?

(sorry, couldn't resist.)

As for the topic, I am interested to know. I am eznic challenged.


--
73 for now
Buck
N4PGW

I am a software engineer but, I am glad you commented on eznec--I am finding
it a bit of challenge to utilize it meaningfully--it has brought me to my
knees and humbled me.
You know the old saying, "Garbage in, Garbage out", eznec just won't arrange
my garbage in a meaninful way.

Warmest regards

--
Hay, if'n ya'll cun't konstructivly partecipete in this har disscusion, haw
aboot speel-checkin it fer me?


"Buck" wrote in message
...
On Tue, 29 Mar 2005 13:41:50 -0800, "John Smith"
wrote:

Becareful Buck!!! It is catching, you are starting to think like me!

Regards


hmmm, maybe I should killfile you for being contagious?

(sorry, couldn't resist.)

As for the topic, I am interested to know. I am eznic challenged.


--
73 for now
Buck
N4PGW

On Tue, 29 Mar 2005 15:09:25 -0500, Buck wrote:

How well would that work for shortening a J-Pole? would it be better
to use a shortened 1/2 wave dipole or would the J-Pole design be
better?

Hi Buck,

You may have noticed the vacuum of response - most have already seen
this movie and skipped out. However, for your benefit:

Like any small antenna, narrow bandwidth. Like any Hi-Z antenna, very
skitterish. Like any small antenna, lower gain.

For a helix standing roughly 4M tall for 40M band (which isn't
particularly short) under an 8 spoke top hat 6M wide, this exhibits a
drive point Z of 40000 Ohms. Put 100W into it and you will see 2KV at
the connector. That should take care of grass growing nearby.

EZNEC boldly announces there is loss, and the best gain is -2.6dBi.

The bandwidth spanned from 7.18MHz to 7.25MHz.

From there it is only a matter of adding the critical matching
section.

OR

Throw away the helix and use a straight support, shorten the 8 spoke
top hat to 4M wide and the drive point is an easier match at 13 Ohms.
No lethal voltages at the drive point, lower loss, more gain (albeit
of 0.65dBi), more bandwidth 7.14MHz to 7.4MHz.

Still reduces to it's hardly worth the effort to change from one to
the other, but all the signs point to a better implementation without
the air cooled wire wound resistor. If you want to keep a coil in the
picture, you can put it in the conventional place, shorten the top hat
spokes yet some more, and find no more gain, and less bandwidth.

OR

Buy an SGC which proudly proclaims it will match a wet string.

OR

Throw away all this folderol, and build a full size antenna (roughly
twice as tall as these gomers). No matching issue, bandwidth up the
kazoo (7-7.5 MHz), no appreciable change in gain though (in other
words, that imperceptible 1dB delta).

All modeling performed using "Real/MiniNEC Ground" (not usually my
choice, but then no one else has stepped up to the bar).

OR

Go watch a movie you haven't seen before, it may have a surprise in
it.

73's
Richard Clark, KB7QHC

My gawd! Is this the same Richard Clark which I just reported to mental
health for a three day observation???
Quick, where is a phone--I will and cancel that! grin

Regards

--
Hay, if'n ya'll cun't konstructivly partecipete in this har disscusion, haw
aboot speel-checkin it fer me?


"Richard Clark" wrote in message
...
On Tue, 29 Mar 2005 15:09:25 -0500, Buck wrote:

How well would that work for shortening a J-Pole? would it be better
to use a shortened 1/2 wave dipole or would the J-Pole design be
better?

Hi Buck,

You may have noticed the vacuum of response - most have already seen
this movie and skipped out. However, for your benefit:

Like any small antenna, narrow bandwidth. Like any Hi-Z antenna, very
skitterish. Like any small antenna, lower gain.

For a helix standing roughly 4M tall for 40M band (which isn't
particularly short) under an 8 spoke top hat 6M wide, this exhibits a
drive point Z of 40000 Ohms. Put 100W into it and you will see 2KV at
the connector. That should take care of grass growing nearby.

EZNEC boldly announces there is loss, and the best gain is -2.6dBi.

The bandwidth spanned from 7.18MHz to 7.25MHz.

From there it is only a matter of adding the critical matching
section.

OR

Throw away the helix and use a straight support, shorten the 8 spoke
top hat to 4M wide and the drive point is an easier match at 13 Ohms.
No lethal voltages at the drive point, lower loss, more gain (albeit
of 0.65dBi), more bandwidth 7.14MHz to 7.4MHz.

Still reduces to it's hardly worth the effort to change from one to
the other, but all the signs point to a better implementation without
the air cooled wire wound resistor. If you want to keep a coil in the
picture, you can put it in the conventional place, shorten the top hat
spokes yet some more, and find no more gain, and less bandwidth.

OR

Buy an SGC which proudly proclaims it will match a wet string.

OR

Throw away all this folderol, and build a full size antenna (roughly
twice as tall as these gomers). No matching issue, bandwidth up the
kazoo (7-7.5 MHz), no appreciable change in gain though (in other
words, that imperceptible 1dB delta).

All modeling performed using "Real/MiniNEC Ground" (not usually my
choice, but then no one else has stepped up to the bar).

OR

Go watch a movie you haven't seen before, it may have a surprise in
it.

73's
Richard Clark, KB7QHC

....I will call and cancel that... even!

--
Hay, if'n ya'll cun't konstructivly partecipete in this har disscusion, haw
aboot speel-checkin it fer me?


"John Smith" wrote in message
...
My gawd! Is this the same Richard Clark which I just reported to mental
health for a three day observation???
Quick, where is a phone--I will and cancel that! grin

Regards

--
Hay, if'n ya'll cun't konstructivly partecipete in this har disscusion,
haw
aboot speel-checkin it fer me?


"Richard Clark" wrote in message
...
On Tue, 29 Mar 2005 15:09:25 -0500, Buck wrote:

How well would that work for shortening a J-Pole? would it be better
to use a shortened 1/2 wave dipole or would the J-Pole design be
better?

Hi Buck,

You may have noticed the vacuum of response - most have already seen
this movie and skipped out. However, for your benefit:

Like any small antenna, narrow bandwidth. Like any Hi-Z antenna, very
skitterish. Like any small antenna, lower gain.

For a helix standing roughly 4M tall for 40M band (which isn't
particularly short) under an 8 spoke top hat 6M wide, this exhibits a
drive point Z of 40000 Ohms. Put 100W into it and you will see 2KV at
the connector. That should take care of grass growing nearby.

EZNEC boldly announces there is loss, and the best gain is -2.6dBi.

The bandwidth spanned from 7.18MHz to 7.25MHz.

From there it is only a matter of adding the critical matching
section.

OR

Throw away the helix and use a straight support, shorten the 8 spoke
top hat to 4M wide and the drive point is an easier match at 13 Ohms.
No lethal voltages at the drive point, lower loss, more gain (albeit
of 0.65dBi), more bandwidth 7.14MHz to 7.4MHz.

Still reduces to it's hardly worth the effort to change from one to
the other, but all the signs point to a better implementation without
the air cooled wire wound resistor. If you want to keep a coil in the
picture, you can put it in the conventional place, shorten the top hat
spokes yet some more, and find no more gain, and less bandwidth.

OR

Buy an SGC which proudly proclaims it will match a wet string.

OR

Throw away all this folderol, and build a full size antenna (roughly
twice as tall as these gomers). No matching issue, bandwidth up the
kazoo (7-7.5 MHz), no appreciable change in gain though (in other
words, that imperceptible 1dB delta).

All modeling performed using "Real/MiniNEC Ground" (not usually my
choice, but then no one else has stepped up to the bar).

OR

Go watch a movie you haven't seen before, it may have a surprise in
it.

73's
Richard Clark, KB7QHC

On Thu, 31 Mar 2005 23:11:04 -0800, "John Smith"
wrote:

My gawd! Is this the same Richard Clark which I just reported to mental
health for a three day observation???

Hi Brett,

Catch a particularly interesting movie? A good one for programmers
from Argentina: "Una Sombra Ya Pronto Seras" comes to mind. However,
in a diverse crowd at the end of the road and for those willing to
truck 2 tons of nitro over the Andes: "Le Salaire De La Peur."

For Art, all of this is like sitting through "The Saragossa
Manuscript." ;-)

73's
Richard Clark, KB7QHC

Err, Richard, I like the other personality better, yanno, the technical one
which imitated sanity in a believable manner?

Hey, just how many of those multiple personalities do you have? But, only
one sane one?



Regards


--
Hay, if'n ya'll cun't konstructivly partecipete in this har disscusion, haw
aboot speel-checkin it fer me?


"Richard Clark" wrote in message
...
On Thu, 31 Mar 2005 23:11:04 -0800, "John Smith"
wrote:

My gawd! Is this the same Richard Clark which I just reported to mental
health for a three day observation???

Hi Brett,

Catch a particularly interesting movie? A good one for programmers
from Argentina: "Una Sombra Ya Pronto Seras" comes to mind. However,
in a diverse crowd at the end of the road and for those willing to
truck 2 tons of nitro over the Andes: "Le Salaire De La Peur."

For Art, all of this is like sitting through "The Saragossa
Manuscript." ;-)

73's
Richard Clark, KB7QHC

On Fri, 1 Apr 2005 06:33:17 -0800, "John Smith"
wrote:

Hey, just how many of those multiple personalities do you have? But, only
one sane one?

Hi Brett,

How many screen names do you have? Is your serial multiple
personality somehow better than what you see as parallel multiple
personality? What about false personality? What you perceive as a
talent in yourself is projected to be the mark of a fool upon another.
In this group, we observe the laws of what are called symmetry and
reciprocity - two very strong, scientific principles.

The responsibility of posting to a newsgroup is that only you choose
what you think is important to discuss. Of your choices to go
technical or metaphysical (or CB truckers), I have no control over. I
have responded to your technical comments and your sidebars (as now)
equally.

Upon my analysis of the Top Hat on J-Pole you could have acknowledged
the results, asked questions about particulars of implementation, or
challenged the results to greater scrutiny - and simply ignored side
topics. I observe you have not shown any interest in obtaining the
model used. We share models as a commonplace expectation of peer
review. Any of this would have constituted technical correspondence.

Instead, the side-topics attracted your notice and you took that route
instead. I welcome all correspondence, but I am not responsible for
what you respond to when there are choices - especially when you can
add topics as well (a privilege I exercise, you present above, and I
do not object to in anyone).

So, as I offered so long ago:
1. Adding a coil offers loss [demonstrated];
2. Physical size in relation to wavelength dominates launch
characteristics [demonstrated];
3. It barely matters [less than 1dB].

The launch gain of a half wave radiator did not appear simply because
a much shorter antenna is ginned up to be antiresonant [demonstrated].

This also returns me to an unanswered question (also technical):
The rubber duckie antenna is certainly useful for some situations, however,
it is better if it stays on the walkie-talkie and we use another design for
portable or base use.
Given this opprobrium, what makes its cousin for 20M more suitable?

OR

I am both content, and competent to discuss those movies that would
have been more enjoyable than the alternative of sitting through the
snooze of finding gain from a small antenna.

OR

I am content discussing how to obtain the most gain from a small
antenna, or simply pointing you at 300 pages of results I've done
years ago.

73's
Richard Clark, KB7QHC