TOA is deemed to be the angle at which maximum gain occurs.
Seems like you are fishing for something, but you will not get
it from me.

Art


"Richard Clark" wrote in message
...
On Fri, 04 Mar 2005 05:24:23 GMT, "
wrote:

With my antenna having a TOA of 10 degrees

Hi Art,

All antennas have a TOA of 10 degrees. That is possibly why Reggie
(and others) generally advise that worshiping at the altar of TOA is
illusory. Without some real data, like 0.2 dBi @ 10°, simply saying
you have a TOA of 10 degrees is like trying to sell this wonderful car
because it has brakes that work.

73's
Richard Clark, KB7QHC

wrote:
TOA is deemed to be the angle at which maximum gain occurs.
Seems like you are fishing for something, but you will not get
it from me.

The problem seems to be that the definition of TOA is
not standardized. Literally, TOA can be any angle but
has a special meaning when quoting EZNEC. Neither my
antenna books nor "The IEEE Dictionary" define TOA.
I did a search for "take off angle" and "TOA" on my
ARRL Antenna Book CD with zero results.
--
73, Cecil, W5DXP

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Exactly.
After all there is some gain at 0 degrees, very small of course,
but would anybody consider that as the TOA.?
It appears that many consider TOA of little importance, but just consider
a antenna with a single feed point such as a big yagi for 20m with say
a 60 foot boom. Even with the high gain its TOA is in the region of 13
degrees
where smaller boom antennas will be about 14 degrees.
Now say we have another antenna with a single feed that has a TOA of
10 degrees with the same gain as the big yagi !.
Which antenna will OPEN the band ? They do NOT open at the same time
even tho they have the same gain so where Reg states that no amount of
changing or shaking the antennas is going to make a scrap of difference to
the" hop" distance is patently incorrect.
As an aside losses in a signal is directly related to the number of hops
that it takes
one hop less to communicate means a louder signal.
You can design a single feed antenna with a TOA of +/- 25 percent
from the norm which makes a terrific distance to the "hop " distance,
especially
if the lower contour of the main lobe is below the competition, as the lobe
will
be noticable thinner with a low TOA. You can ,ofcourse, lower the take off
angle
by using multiple antenna feeds ie stacking but that is another matter of
discussion.
Regards
Art




"Cecil Moore" wrote in message
...
wrote:
TOA is deemed to be the angle at which maximum gain occurs.
Seems like you are fishing for something, but you will not get
it from me.

The problem seems to be that the definition of TOA is
not standardized. Literally, TOA can be any angle but
has a special meaning when quoting EZNEC. Neither my
antenna books nor "The IEEE Dictionary" define TOA.
I did a search for "take off angle" and "TOA" on my
ARRL Antenna Book CD with zero results.
--
73, Cecil, W5DXP

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News==----
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Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption
=----

On Fri, 04 Mar 2005 17:19:26 GMT, "
wrote:
Now say we have another antenna with a single feed that has a TOA of
10 degrees with the same gain as the big yagi !.

Hi Art,

Simply using EZNEC's freely available yagi design, I can come up with
a 11.4 dBi figure at 10 degrees. Can you say we have another antenna
with a single feed that has a TOA of 10 degrees with more gain that
this?

73's
Richard Clark, KB7QHC

I don't think there would be a problem in beating that!
I would expect many could come up with one better than that at a feed
point height
of 1 wave length. Isn't the max gain theoretical obtainable just short of
16dbi ?
Allow for 0.5 db max losses seems like 15.5 dbi is obtainable.
( using perfect flat terrain ofcourse with a 60 foot boom 'big' yagi)
With all the experts that reside on this group plus a zillion of antenna
reference books
I expect many to come up with antennas better than that.
Isn';t all now known about antennas and placed in print? (Grin)
It just needs is a bit of research or an expert to share his knowledge
with civility.
Art





"Richard Clark" wrote in message
...
On Fri, 04 Mar 2005 17:19:26 GMT, "
wrote:
Now say we have another antenna with a single feed that has a TOA of
10 degrees with the same gain as the big yagi !.

Hi Art,

Simply using EZNEC's freely available yagi design, I can come up with
a 11.4 dBi figure at 10 degrees. Can you say we have another antenna
with a single feed that has a TOA of 10 degrees with more gain that
this?

73's
Richard Clark, KB7QHC

On Fri, 04 Mar 2005 18:33:41 GMT, "
wrote:
I expect many to come up with antennas better than that.

Hi Art,

Thanx, I just needed you to confirm that you, in fact, did not have
such a design.

73's
Richard Clark, KB7QHC

Do you really think that I wasn't wise to the games you play ?
You was gearing up for an augument so I gave you nothing you
could argue about. Check mate !

Art



"Richard Clark" wrote in message
...
On Fri, 04 Mar 2005 18:33:41 GMT, "
wrote:
I expect many to come up with antennas better than that.

Hi Art,

Thanx, I just needed you to confirm that you, in fact, did not have
such a design.

73's
Richard Clark, KB7QHC

wrote:
You can ,ofcourse, lower the take off angle
by using multiple antenna feeds ie stacking
but that is another matter of discussion.

Art, if you really want perfect control of your
TOA, get a satellite tracking system. :-)
--
73, Cecil, W5DXP

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Judging by newsgroup postings, I'd say the most common meaning of
"takeoff angle" is "that elevation angle at which an antenna radiates".
For this to have any meaning, it's necessary to assume that the antenna
radiates at only one angle and no others. Since this is a false
assumption, the term "takeoff angle" as used by most amateurs is
meaningless. I've never seen the term in any non-amateur publication --
it seems to be in the same category as "capture area" and "S unit",
creations which only amateurs seem to have a need for.

As you say, it has a precise definition as used in EZNEC. The first
versions of ELNEC, incidentally, didn't report "takeoff angle" because I
thought it to be unnecessary to point out what anyone can see from a
glance at the pattern, and felt that the term would be misunderstood and
misused. Turns out I was right -- it's misunderstood and misused,
despite my best effort at explicitly defining it. But you've gotta give
the customer what he wants, not what he needs.

Roy Lewallen, W7EL

Cecil Moore wrote:
wrote:

TOA is deemed to be the angle at which maximum gain occurs.
Seems like you are fishing for something, but you will not get
it from me.


The problem seems to be that the definition of TOA is
not standardized. Literally, TOA can be any angle but
has a special meaning when quoting EZNEC. Neither my
antenna books nor "The IEEE Dictionary" define TOA.
I did a search for "take off angle" and "TOA" on my
ARRL Antenna Book CD with zero results.
--
73, Cecil, W5DXP

Don't professionals use the term? Seems like it shows up in pro computor
programs.
Doesn't the Antenna handbook refer to TOA ? I do know they made a graph of
incoming
RF ray angles which amounts to the same thing. What is wrong with the common
perception
that it is the angle of maximum gain?
If you were designing a 'point to point' antenna would you not look for the
angle of maximum gain?
If so what would you call that angle ? If you are refering to an antenna
lobe pattern could you not invoke
the +/- 3 db points as used in many other places in antenna work?
Methinks that people are looking for problems to argue about
Art





"Roy Lewallen" wrote in message
...
Judging by newsgroup postings, I'd say the most common meaning of "takeoff
angle" is "that elevation angle at which an antenna radiates". For this to
have any meaning, it's necessary to assume that the antenna radiates at
only one angle and no others. Since this is a false assumption, the term
"takeoff angle" as used by most amateurs is meaningless. I've never seen
the term in any non-amateur publication --
it seems to be in the same category as "capture area" and "S unit",
creations which only amateurs seem to have a need for.

As you say, it has a precise definition as used in EZNEC. The first
versions of ELNEC, incidentally, didn't report "takeoff angle" because I
thought it to be unnecessary to point out what anyone can see from a
glance at the pattern, and felt that the term would be misunderstood and
misused. Turns out I was right -- it's misunderstood and misused, despite
my best effort at explicitly defining it. But you've gotta give the
customer what he wants, not what he needs.

Roy Lewallen, W7EL

Cecil Moore wrote:
wrote:

TOA is deemed to be the angle at which maximum gain occurs.
Seems like you are fishing for something, but you will not get
it from me.


The problem seems to be that the definition of TOA is
not standardized. Literally, TOA can be any angle but
has a special meaning when quoting EZNEC. Neither my
antenna books nor "The IEEE Dictionary" define TOA.
I did a search for "take off angle" and "TOA" on my
ARRL Antenna Book CD with zero results.
--
73, Cecil, W5DXP