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

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

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

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!

wrote:
As gain increases with a yagi design the forward
lobe narrows. So to the gurus of this group, what
actualy creates the narrowing of the forward lobes ?
______________________

A good analogy that needs no math to understand is that of squeezing an
inflated balloon from its normally spherical shape into whatever shape is
more appropriate for the application. There is a given volume of air in
that balloon. If you want the surface of the balloon to extend further from
the origin of its original sphere, the new shape must be narrower in one or
more planes than the original shape.

The shape changes can come from squeezing the balloon (pattern)
horizontally, vertically, or in combination -- which, in antenna hardware is
accomplished by an appropriate array of, and feed system for, its radiating
elements.

RF

"Richard Fry" wrote in message
...
wrote:
As gain increases with a yagi design the forward
lobe narrows. So to the gurus of this group, what
actualy creates the narrowing of the forward lobes ?
______________________

A good analogy that needs no math to understand is that of squeezing an
inflated balloon from its normally spherical shape into whatever shape is
more appropriate for the application. There is a given volume of air in
that balloon. If you want the surface of the balloon to extend further
from the origin of its original sphere, the new shape must be narrower in
one or more planes than the original shape.

The shape changes can come from squeezing the balloon (pattern)
horizontally, vertically, or in combination -- which, in antenna hardware
is accomplished by an appropriate array of, and feed system for, its
radiating elements.

Right..... so what creats it, this "squeezing" that you talk about and from
where
does this "squeezing force come from in an "appropiate"array?
That's what I was asking not a discussion of what the
Yagi array produces. Why does the lobe narrow?
Art




RF

" wrote:
The shape changes can come from squeezing the balloon (pattern)
horizontally, vertically, or in combination -- which, in antenna hardware
is accomplished by an appropriate array of, and feed system for, its
radiating elements.

Right..... so what creats it, this "squeezing" that you talk about and
from where does this "squeezing force come from in an "appropiate"array?
That's what I was asking not a discussion of what the Yagi array
produces. Why does the lobe narrow?
______________

Narrowing is the natural result of the vector addition of the separate EM
waves radiated from the individual sources comprising the Yagi (or any other
kind of directional array).

RF

Great! I would disagree with respect to "any other type of directional array
but I would like a further insight to the mechanics of vector array that
produces
this phenomina. I would like to reproduce this effect else where if I could.
Regards
Art



"Richard Fry" wrote in message
...
" wrote:
The shape changes can come from squeezing the balloon (pattern)
horizontally, vertically, or in combination -- which, in antenna
hardware is accomplished by an appropriate array of, and feed system
for, its radiating elements.

Right..... so what creats it, this "squeezing" that you talk about and
from where does this "squeezing force come from in an "appropiate"array?
That's what I was asking not a discussion of what the Yagi array
produces. Why does the lobe narrow?
______________

Narrowing is the natural result of the vector addition of the separate EM
waves radiated from the individual sources comprising the Yagi (or any
other kind of directional array).

RF

" wrote
Great! I would disagree with respect to "any other type of directional
array' but I would like a further insight to the mechanics of vector
array that produces this phenomina. I would like to reproduce this
effect else where if I could.
___________

Suggest you get this background from a good read of just about any of the
many antenna textbooks available. It's a bit much to deal with in a NG
forum.

RF

In article bkE1e.110371$Ze3.24514@attbi_s51,
wrote:

Right..... so what creats it, this "squeezing" that you talk about and from
where
does this "squeezing force come from in an "appropiate"array?

There is no "force" in the usual sense of pressure on a physical
balloon. That's because the "balloon" is not an object. It's simply
a mathematical abstraction - a drawing of lines of equal RF power
levels on a graph having a certain set of axes.

To think that there's a specific 'force' squeezing the 'balloon', is
somewhat like trying to travel from east to west by pulling yourself
along the lines of longitude. Hey, the lines are there on the globe,
they're there on the map, why can't I just walk along the lines?

There's nothing "pushing" on the "boundaries" of the lobe, because
there is no lobe in the physical sense. It's not a separate and
distinct object.

To understand why there's a change in the shape that we visualize (and
that's all that the lobe shape is - a selective visualization), we
have to step down to the underlying phenomenon and see what's changing.

Because the conventional "lobe shape" is simply the result of plotting
the strength of the RF energy coming from the antenna, the answer is
simple. The lobe's shape is changing, because the amount of RF energy
being transmitted in the different directions is changing...

.... and *that* happens because the phase-and-location details of the
various radiators (and re-radiators) in the antenna system are being
altered.

Different radiator and re-radiator locations, intensities, and phases...

.... cause different "sum of vectors" results ...

.... which changes the strength of the RF received ...

.... which, when we walk around and try to locate the points
having equal RF field strength, means that we walk along
different paths ...

.... which means that we draw the lines on the map in
different places ...

.... which means that the "lobes" now have a different
shape.

--
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!