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Art Unwin September 13th 08 12:43 AM

Tilted radiator
 
A sloper antenna when resonant produces more gain
than a vertical dipole resonant at the same frequency.
True or false? prove it

Dave September 13th 08 01:12 AM

Tilted radiator
 

"Art Unwin" wrote in message
...
A sloper antenna when resonant produces more gain
than a vertical dipole resonant at the same frequency.
True or false? prove it


run it through your neutrino based weak force enabled optimizer program and
see what you get!



Art Unwin September 13th 08 01:38 AM

Tilted radiator
 
On Sep 12, 7:12*pm, "Dave" wrote:
"Art Unwin" wrote in message

...

A sloper antenna when resonant produces more gain
than a vertical dipole resonant at the same frequency.
True or false? prove it


run it through your neutrino based weak force enabled optimizer program and
see what you get!


a tilted radiator

Frank[_5_] September 13th 08 01:47 AM

Tilted radiator
 

"Art Unwin" wrote in message
...
A sloper antenna when resonant produces more gain
than a vertical dipole resonant at the same frequency.
True or false? prove it


Model parameters for sloping dipole: 60 ft at one end
13.3 ft at the other (45 deg slope). Horizontal dipole
at 60 ft. Length of both antennas 66 ft. Sloping dipole
resonant at 7.225 MHz, same length horizontal 7.3 MHz.
Average ground parameters: conductivity 5 mS/m, and
relative permittivity 13. Horizontal dipole maximum
gain off the sides (As expected). Sloping antenna
double lobed pattern with maximum gain at 80 degrees
either side of lowest end. Softwa Nittany's GNEC.

Simulation results:

EL. angle Sloping dipole Horizontal dipole
(deg.) Gain (dbi) Gain (dbi)
10 -1.5 +1.2
20 +1.4 +6
30 +2.4 +7
40 +2.7 +6.4
50 +2.7 +4.7
70 +2 -0.6
90 +1.5 -3.5

73, Frank



Frank[_5_] September 13th 08 01:55 AM

Tilted radiator
 
Simulation results:

EL. angle Sloping dipole Horizontal dipole
(deg.) Gain (dbi) Gain (dbi)
10 -1.5 +1.2
20 +1.4 +6
30 +2.4 +7
40 +2.7 +6.4
50 +2.7 +4.7
70 +2 -0.6
90 +1.5 -3.5

73, Frank


PS. Finite ground (Sommerfeld/Norton method).



Art Unwin September 13th 08 02:27 AM

Tilted radiator
 
On Sep 12, 7:55*pm, "Frank" wrote:
Simulation results:


EL. angle * *Sloping dipole *Horizontal dipole
(deg.) * * * * * *Gain (dbi) * *Gain (dbi)
10 * * * * * * * * *-1.5 * * * * * * +1.2
20 * * * * * * * * *+1.4 * * * * * * +6
30 * * * * * * * * *+2.4 * * * * * * +7
40 * * * * * * * * *+2.7 * * * * * * +6.4
50 * * * * * * * * *+2.7 * * * * * * +4.7
70 * * * * * * * * *+2 * * * * * * * *-0.6
90 * * * * * * * * *+1.5 * * * * * * -3.5


73, *Frank


PS. *Finite ground (Sommerfeld/Norton method).


FINE FRANK DAVE WILL SUPPLY THE ARRANGEMENT THAT GIVES MAXIMUM GAIN
as well as being resonant. Yours are not resonant as I assume you
would have supplied the info
The navy would not change to a antenna that was not resonant.
Art

Frank[_5_] September 13th 08 02:41 AM

Tilted radiator
 
FINE FRANK DAVE WILL SUPPLY THE ARRANGEMENT THAT GIVES MAXIMUM GAIN
as well as being resonant. Yours are not resonant as I assume you
would have supplied the info
The navy would not change to a antenna that was not resonant.
Art

The antenna is resonant.

Input impedance: 84.8 + j 1.3 at 7.25 MHz.

Not that I regard resonance as having any significance other than
the input impedance is resistive.

Frank



Art Unwin September 13th 08 03:33 AM

Tilted radiator
 
On Sep 12, 8:41*pm, "Frank" wrote:
FINE FRANK DAVE WILL SUPPLY THE ARRANGEMENT THAT GIVES MAXIMUM GAIN
as well as being resonant. Yours are not resonant as I assume you
would have supplied the info
The navy would not change to a antenna that was not resonant.
Art

The antenna is resonant.

Input impedance: 84.8 + j 1.3 *at 7.25 MHz.

Not that I regard resonance as having any significance other than
the input impedance is resistive.

Frank


Correct, as long as it is resistive. So what angle did the Navy tip
their antennas to achieve maximum gain?
They were not satisfied with the vertical antennas performance and
wanted something better.
So the question is what needs to be done to provide better performance
ie gain?
Yup they experimented in each and every way and fell upon.....what?
Even tho they cannot explain it.
David can tell you in less than 5 minuits which is the time the
program requires to provide the answer.
Art Unwin KB9MZ......xg

Dave September 13th 08 12:08 PM

Tilted radiator
 

"Art Unwin" wrote in message
...
On Sep 12, 7:55 pm, "Frank" wrote:
The navy would not change to a antenna that was not resonant.


sure they would, there is no reason to have a resonant antenna... a
non-resonant one radiates just fine when you have the power to get the
current into it. its all in the driving and matching networks.



Myron A. Calhoun September 13th 08 12:17 PM

Tilted radiator
 
On Sep 12, 7:47*pm, "Frank" wrote:
"Art Unwin" wrote in message

...

A sloper antenna when resonant produces more gain
than a vertical dipole resonant at the same frequency.
True or false? prove it


Model parameters for sloping dipole: 60 ft at one end
13.3 ft at the other (45 deg slope). *Horizontal dipole
at 60 ft. *Length of both antennas 66 ft. *Sloping dipole
resonant at 7.225 MHz, same length horizontal 7.3 MHz.
Average ground parameters: conductivity 5 mS/m, and
relative permittivity 13. *Horizontal dipole maximum
gain off the sides (As expected). *Sloping antenna
double lobed pattern with maximum gain at 80 degrees
either side of lowest end. *Softwa Nittany's GNEC.

Simulation results:

..... snip ....

The original question said VERTICAL dipole , but you modeled a
HORIZONTAL dipole? Or was one of these just a typo?

FWIW, I modeled your horizontal dipole in EZNEC and came up with
slightly DIFFERENT results:
Resonant frequency about 7.335 Mhz
Resistance about 81 ohms
Max gain about 6.54 dBi at 30 degrees
I am INexperienced in using EZNEC and wonder if I'm doing something
wrong?

--Myron, W0PBV.


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