As gain increases with a yagi design the forward
lobe narrows . With high gain yagi's the lobe
becomes so narrow it is deemed to be a hinderence
instead of an advantage. To overcome this perceived
problem one has to know what causes it.
So to the gurus of this group, what actualy creates
the narrowing of the forward lobes ?
End effects perhaps!
Regards
Art

On Sun, 27 Mar 2005 16:20:58 GMT, "
wrote:

As gain increases with a yagi design the forward
lobe narrows .

Let's certainly hope so.

With high gain yagi's the lobe
becomes so narrow it is deemed to be a hinderence
instead of an advantage.

Huh, I didn't know this...for several decades now I've thought it was
an advantage.

For example my EME friends and I have always believed that focusing
the available transmit power on the moon on transmit and rejecting
stellar background noise on receive was desirable. How did we go so
wrong?

On Sun, 27 Mar 2005 16:20:58 GMT, "
wrote:
To overcome this perceived problem one has to know what causes it.

Hi Art,

Replace the defective yagi with an omni. To re-obtain gain without
perceived problem - add amplification.
So to the gurus of this group, what actualy creates the narrowing of the forward lobes ?
Sinus pressure.

73's
Richard Clark, KB7QHC

In article K3B1e.8558$NW5.7100@attbi_s02,
wrote:

As gain increases with a yagi design the forward
lobe narrows . With high gain yagi's the lobe
becomes so narrow it is deemed to be a hinderence
instead of an advantage. To overcome this perceived
problem one has to know what causes it.
So to the gurus of this group, what actualy creates
the narrowing of the forward lobes ?
End effects perhaps!

Conservation of energy.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

"Wes Stewart" wrote in message
news
On Sun, 27 Mar 2005 16:20:58 GMT, "
wrote:

As gain increases with a yagi design the forward
lobe narrows .

Let's certainly hope so. But if you knew the answer you could
then use the knoweledge to extend the narrowing to provide more gain.
All is known about antennas isn't it?

It doesn't with my antenna where the lobe gets larger
as radiation is deflected to the forward direction.
Obviously with a yagi cancellation is occuring as well as addition.




With high gain yagi's the lobe
becomes so narrow it is deemed to be a hinderence
instead of an advantage.

Huh, I didn't know this...for several decades now I've thought it was

an advantage.

You are not alone as I thought it meant quieter contacts but it is said
(ARRL publication) that it then becomes more difficult to aim, ala the
rombic.
That's why I see my antenna's flattening of the main lobe without loss in
beam
width an advantage.



For example my EME friends and I have always believed that focusing
the available transmit power on the moon on transmit and rejecting
stellar background noise on receive was desirable. How did we go so
wrong?



But back to the question.
-------------------------------------

Do you know what creates the narrowing of the main lobe ?
It only takes one diffinitive post from a real guru to explain and then
the others will follow. Until the real guru comes forward with an
explanation
all others will procrastinate and avoid the question without giving
a hint that they do not know and are awaiting the explanation from a real
guru.

If you actually know Wes then jump in so others may follow.

Regards
Art



..

Richard
Why do you feel compelled to post when you apparently do not know the
answer.
Your response is pure rubbish
Why not wait for the real guru to post so you can float in on his or her's
coatails ?
You seem to have a penchant for posting in such oblique language in the hope
that
others will see you as possibly knoweledgable but not understood by the
lesser educated.
Your degree in Shakespeare has sure muddled your thinking with respect to
engineering.
Art





"Richard Clark" wrote in message
...
On Sun, 27 Mar 2005 16:20:58 GMT, "
wrote:
To overcome this perceived problem one has to know what causes it.

Hi Art,

Replace the defective yagi with an omni. To re-obtain gain without
perceived problem - add amplification.
So to the gurus of this group, what actualy creates the narrowing of the
forward lobes ?
Sinus pressure.

73's
Richard Clark, KB7QHC

In article FUB1e.8710$NW5.8590@attbi_s02,
wrote:

It doesn't with my antenna where the lobe gets larger
as radiation is deflected to the forward direction.

There is a harsh limit, imposed by physics, as to how much gain that
approach can give you.

If all of the energy from one hemisphere is redirected into the other
hemisphere, and if the forward-direction pattern shape does not change
(the forward lobe is not narrowed), then you have a forward gain of 3
dB (2:1 power ratio increase). You *cannot* have more, as this would
require that the antenna be radiating more power than it receives from
its input.

A Moxon antenna is, to a first approximation, a pretty good example of
this approach - it has very little energy in the rear hemisphere, and
a broad forward lobe. There are various two-driven-element array
designs which achieve a similar pattern and result.

Obviously with a yagi cancellation is occuring as well as addition.

You are trying to draw a distinction between "deflection" and
"cancellation" which I believe is invalid. Both are simply ways of
describing the result of the "sum of vectors" effects of having energy
from multiple radiators (driven or passive) combining in different
phases at different locations. Same math, two different words.

Do you know what creates the narrowing of the main lobe ?

Conservation of energy *requires* that the main lobe be narrowed, if
you wish to achieve more gain than you can get by simply redistibuting
the rear-ward energy in the forward direction.

A super-high-gain antenna *cannot* have a wide, uniform beam-width in
both azimuth and elevation.

As usual for your postings, Art, it's impossible to tell whether your
claims for your antenna are plausible, because you refuse to disclose
*anything* (either the invention, or the results you claim) in any
halfway-tanglible form (e.g. models, specific numbers, etc.).

Until you do, I really think it would be to everyone's relief if you'd
follow through with your recent statement that you were going to stop
posting. You're achieving no good result for yourself by contining as
you are.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

On Sun, 27 Mar 2005 17:28:25 GMT, "
wrote:

Richard
Why do you feel compelled to post

Hi Art,

Because straightforward, simple answers seem to baffle you so
outright. See? Each and every post offers what is YOUR
responsibility to discuss, and by your choice you litter the landscape
with thrashing over style instead of content:

Your response is pure rubbish

Let's call it entangled correspondence. Really, Art, you need to go
back to your disclaimers with each posting so we can tell when you
aren't serious.

Why not wait for the real guru to post so you can float in on his or her's
coatails ?

-Whew!- And here I thought you had reserved your venom of "guru" for
me alone. Thanx, that makes me feel so much better that you have
elevated me above that ill-bred population you so love to spit on.

others will see you as possibly knoweledgable but not understood by the
lesser educated.

Well, let's test that by returning to the topic and see which side you
occupy:

Now, do you dispute that sinus pressure DOES NOT create narrowing of
frontal lobes? Even the lesser educated know this for a fact, Art.
Are you suggesting that perceived problems of yagis cannot be cured
with an omni with amplification? Something tells me you already had
an answer for that hidden up your sleeve (without data of course but
perfectly proven with chords and tangents).

I await your Euclidean gymnastics. ;-)

73's
Richard Clark, KB7QHC

"Dave Platt" wrote in message
...
In article FUB1e.8710$NW5.8590@attbi_s02,
wrote:

It doesn't with my antenna where the lobe gets larger
as radiation is deflected to the forward direction.

There is a harsh limit, imposed by physics, as to how much gain that
approach can give you.
Agreed... Do you know what those limits are ?



If all of the energy from one hemisphere is redirected into the other
hemisphere, and if the forward-direction pattern shape does not change
(the forward lobe is not narrowed), then you have a forward gain of 3
dB (2:1 power ratio increase). You *cannot* have more, as this would
require that the antenna be radiating more power than it receives from
its input.

Absolutely incorrect. If I place the air of two balloons ,which reflect the
figure
eight,into one single balloon and where the laws of partial pressures do not
intervene
then you will have a balloon that is round and not elongated as the antenna
books
would have you suggest. "Gain" is a term used to to quantify a small
portion of the
energy contained in the mythical ball of energy. Since the collection of
energy comes
from different directions and phases the energy collection is layered
depending on
the influence of the earth. Thus the layers of radiation are distorted
where one layer
can be squeezed outwards further than other layers, thus the terminology
of "gain"
If you are going to interelate the terms of "gain" and "power" then you must
define
the parameters used to allow that.





A Moxon antenna is, to a first approximation, a pretty good example of
this approach - it has very little energy in the rear hemisphere, and
a broad forward lobe. There are various two-driven-element array
designs which achieve a similar pattern and result.

And the resulting "gain" is ....what?
I have difficulty in getting beyond 16 dbi as any additional energy from the
rear
has very little effect on the diameter of the frontal lobe.


Obviously with a yagi cancellation is occuring as well as addition.


You are trying to draw a distinction between "deflection" and
"cancellation" which I believe is invalid. Both are simply ways of
describing the result of the "sum of vectors" effects of having energy
from multiple radiators (driven or passive) combining in different
phases at different locations. Same math, two different words.

Yes I agree because of conservation laws e.t.c . When cancellation occurs
then energy creats energy in another direction similar to pulling steel
apart in tension
(or using compression) the steel becomes narrower before severing occurrs.
This thinning or "waisting" is created by the additional forces created at
90 degrees
to the tensile forces and where the break actually occurrs at 45 degrees
and not at right angles.

Do you know what creates the narrowing of the main lobe ?



Conservation of energy *requires* that the main lobe be narrowed, if
you wish to achieve more gain than you can get by simply redistibuting
the rear-ward energy in the forward direction.

This is what you alluded to before and it is still incorrect
What "requires" what ? And how is this conclusion generating
an elongated lobe?


A super-high-gain antenna *cannot* have a wide, uniform beam-width in
both azimuth and elevation.

Don't know how you can say that unless somehow you generated a single lobe.
Now that would be interesting




As usual for your postings, Art, it's impossible to tell whether your
claims for your antenna are plausible, because you refuse to disclose
*anything* (either the invention, or the results you claim) in any
halfway-tanglible form (e.g. models, specific numbers, etc.).


My antenna is somewhat related thus my interest in what creates an elongated
lobe
which is formed using Yagi principles.
The question however, is specifically related to Yagi's
and its narrowed lobes.
Do you know what it is that creats an elongated lobe
on a high gain yagi i.e not totally round.?
Nothing more, nothing less.
Regards
Art





Until you do, I really think it would be to everyone's relief if you'd
follow through with your recent statement that you were going to stop
posting. You're achieving no good result for yourself by contining as
you are.
I have not posted as you have inferred. The question is about Yagi design


AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

On Sun, 27 Mar 2005 18:59:42 GMT, "
wrote:

the problem:
My antenna is somewhat related thus my interest in what creates an elongated lobe
the answer:
which is formed using Yagi principles.

Hi Art,

Your question already answers your question. You have a tendency to
just blow right on taking no notice of this to create the SAME
question again:
The question however, is specifically related to Yagi's
and its narrowed lobes.
Do you know what it is that creats an elongated lobe
on a high gain yagi i.e not totally round.?
formed using Yagi principles. (to quote you)
Nothing more, nothing less.
Exactly.

Now, are we going to be treated by another round of your complaints
about Shakespeare and the quality of gurus; or are you going to stick
with technical discussion and respond to the obvious points?

73's
Richard Clark, KB7QHC