Reg Edwards wrote:

"Cecil Moore"
Sure, just rent a helicopter and make field strength
measurements.

What use would he make of take-off angle if he ever gets to know it.

Maybe it would make him feel good?
Sorta like your Cabernet? :-)
--
73, Cecil http://www.qsl.net/w5dxp

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Charlie wrote:
Hi Richard thx for the reply but in thinking it over it would seem an

unlikely possibility that I could accurately model the 5-BTV with
it's
traps. Did I miss something there?

Hi Charlie, A 5-BTV with 72 radials will have about the same take off
angle as a full size vertical with 72 radials on a given band. This is
assuming the 5-BTV is operated as a 1/4 wave, current fed vertical on
all bands. If it is used as something else, say a 1/2 wave voltage fed
vertical on a given band, then the TOA should be about the same as a
full size 1/2 wave vertical.
As you can tell by other posts, actually measuring the TOA will be
difficult. If you could model full size versions of the 5-BTV on the
bands of interest on a program such as Eznec, you could find out your
TOA. As Reg asked, when you do find it out, what are you gonna do
then?
Gary N4AST

Cecil Moore wrote:

Reg Edwards wrote:

"Cecil Moore"

Sure, just rent a helicopter and make field strength
measurements.


What use would he make of take-off angle if he ever gets to know it.


Maybe it would make him feel good?
Sorta like your Cabernet? :-)


I want to measure the Cabernet of my antenna!!!


- Mike KB3EIA -

Reg
If he knew the TOA could he not ascertain the height of the reflecting layer
using your "hop distance" program:.
I suspect that your program on the same subject has a similar use so perhaps
you could answer your own question.
With my antenna having a TOA of 10 degrees I could work out backwards a
whole mine of information all based around your program, assuming your input
data is correct. Grin
Cheers
Art


"Reg Edwards" wrote in message
...

"Cecil Moore"
Charlie wrote:
Using a Hustler 5-BTV ground mounted with 72 radials. I have heard
about antenna modeling but is there any way to do a real world take
off
angle
measurement???

Sure, just rent a helicopter and make field strength
measurements.

==============================

What use would he make of take-off angle if he ever gets to know it.

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

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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Newsgroups
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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