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.

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.

No, you are correct. I must have been asleep. Funny that nobody
else noticed my error. The difference in your results are probably
due to the fact that EZNEC does not use the Sommerfeld/Norton
ground model which produces more accurate results when the
radiator is near to the ground.

Frank VE6CB

On Sep 13, 10:42*am, "Frank" wrote:
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.

No, you are correct. *I must have been asleep. *Funny that nobody
else noticed my error. *The difference in your results are probably
due to the fact that EZNEC does not use the Sommerfeld/Norton
ground model which produces more accurate results when the
radiator is near to the ground.

Frank VE6CB

well done

NOTE: This is a repost from my sent file. It didn't appear
20 hours or so after I sent it. Sorry if it's a dupe to anybody.
---------------------------------------------------------------------
"Art Unwin" wrote in message
news:7ce5bd71-d583-433d-88f0-

snip

The navy would not change to a antenna that was not resonant.

Perhaps you are speaking of another country's Navy with which you are
well-acquainted.

Having been intimately involved with US Navy electronics for over 45 years
(active duty 1962 -1982; civilian support in multiple capacities 1982 -
2007) I can tell you that our Navy has numerous shipboard and
shore-establishment antennas that are not resonant. Since flexibility in
frequency selection confers a tactical advantage, broadbanding is far more
important. Tuners and couplers of several designs allow non-resonant
antennas to work well.

The closest the Navy gets to resonant antennas is in some special
fixed-frequency applications, like IFF. Of course, antennas are sized for
the application and will probably exhibit resonance within their band of
operation, but that's not the design goal.

On Sep 14, 12:23*am, "Sal M. Onella"
wrote:
NOTE: *This is a repost from my sent file. *It didn't appear
20 hours or so after I sent it. *Sorry if it's a dupe to anybody.
---------------------------------------------------------------------"Art Unwin" wrote in message

news:7ce5bd71-d583-433d-88f0-

snip

The navy would not change to a antenna that was not resonant.

Perhaps you are speaking of another country's Navy with which you are
well-acquainted.

Having been intimately involved with US Navy electronics for over 45 years
(active duty 1962 -1982; civilian support in multiple capacities 1982 -
2007) *I can tell you that our Navy has numerous shipboard and
shore-establishment antennas that are not resonant. *Since flexibility in
frequency selection confers a tactical advantage, broadbanding is far more
important. *Tuners and couplers of several designs allow non-resonant
antennas to work well.

The closest the Navy gets to resonant antennas is in some special
fixed-frequency applications, like IFF. *Of course, antennas are sized for
the application and will probably exhibit resonance within their band of
operation, but that's not the design goal.

These were shore based installations probably in Hawaii or some
island.
With respect to resonance, moving away from such as well as changing
from 15 degrees
(Frank's 30 degrees divided by two)
would provide a pattern of distinct advantage which the navy is
constantly looking for
For a whip tipped at an angle of 15 degrees can provide a forward
pattern of gain which can be a big deal
I anticipate that the navy will gyrate towards helical design where
the addition of a magnetic field will give a pattern of choice
together with resonance the size of a shoebox to reduce the number of
antennas on board.
Thanks for the info, it certainly was not silly As an aside the 15
degrees is the same as found empirically by Kraus
in the pitch angle of a helical, another example of the inclusion of
the weak force in a system in equilibrium !

"Art Unwin" wrote in message
...
Thanks for the info, it certainly was not silly As an aside the 15
degrees is the same as found empirically by Kraus
in the pitch angle of a helical, another example of the inclusion of
the weak force in a system in equilibrium !

where is that weak force in maxwell's equations????? the world is waiting
to know!

On Sep 14, 11:30*am, "Dave" wrote:
"Art Unwin" wrote in message

...

Thanks for the info, it certainly was not silly As an aside the 15
degrees is the same as found empirically by Kraus
in the pitch angle of a helical, another example of the inclusion of
the weak force in a system in equilibrium !

where is that weak force in maxwell's equations????? *the world is waiting
to know!

You will never get it from me. You have done nothing for yourself or
anybody else on this group
so why should I do it for you? Why haven't you done the AO program for
the benefit of the group?
I know it will be embarassing to you but no more than your other posts
have done.
Carry on your fight against change and be among friends. Don't do the
AO program which
acknowledges the weak force that way there can be no change, Just
continue to be a talking head !

These were shore based installations probably in Hawaii or some
island.
With respect to resonance, moving away from such as well as changing
from 15 degrees
(Frank's 30 degrees divided by two)
would provide a pattern of distinct advantage which the navy is
constantly looking for
For a whip tipped at an angle of 15 degrees can provide a forward
pattern of gain which can be a big deal
I anticipate that the navy will gyrate towards helical design where
the addition of a magnetic field will give a pattern of choice
together with resonance the size of a shoebox to reduce the number of
antennas on board.
Thanks for the info, it certainly was not silly As an aside the 15
degrees is the same as found empirically by Kraus
in the pitch angle of a helical, another example of the inclusion of
the weak force in a system in equilibrium !

My original model was for a dipole tilted 45 degrees. The following
analysis is for a 35 ft ground mounted monopole with thirty-six 40 ft
radials buried 1" below an average ground of: conductivity 5 mS/m,
and relative permittivity 13. It is noted that the tilted monopole has
a slight gain opposite to the direction of tilt. The following comparison
is made in the direction of maximum gain. The F/B ratio is nominally
0.2 db, and the gain 0.2 db at lower angles. The measurement was
made on 7.2 MHz, and the input impedance 45 + j 47 ohms.

Take off Angle Vertical 15 deg tilt
(degrees) Gain (dbi) Gain (dbi)
10 -2.5 -2.3
20 -0.2 0
30 0 +0.3
40 -0.8 -0.3
50 -2.3 -1.5
60 -4.6 -3.3
70 -8.0 -5.9
80 -14.0 -9.3
90 Deep null -13.4


CM Monopole with buried radial system.
CE
GW 1 1 0 0 0 0 1 -0.083 0.0026708
GW 37 39 0 1 -0.083 0 40 -0.083 0.0026708
GR 1 36
GS 0 0 0.304800
GE -1 -1 0
GN 2 0 0 0 13.0000 0.0050
FR 0 1 0 0 7.2 0.01
LD 5 0 0 0 5.8001E7
WG monopole_36.NGF
EN


CM 36 Radial Read NGF
CE
GF 0 monopole_36.NGF
GW 73 35 0 9.0587 33.807 0 0 0 0.002671
GS 0 0 0.304800
GE 0 0 0
EX 0 73 35 0 6349.474358 0.00000
LD 5 0 0 0 5.8001E7
RP 0 181 1 1000 -90 270 1.00000 1.00000
EN

73, Frank

On Sep 14, 12:22*pm, "Frank" wrote:
These were shore based installations probably in Hawaii or some
island.
With respect to resonance, moving away from such as well as changing
from 15 degrees
(Frank's 30 degrees divided by two)
would provide a pattern of distinct advantage which the navy is
constantly looking for
For a whip tipped at an angle of 15 degrees can provide a forward
pattern of gain which can be a big deal
I anticipate that the navy will gyrate towards helical design where
the addition of a magnetic field will give a pattern of choice
together with resonance the size of a shoebox to reduce the number of
antennas on board.
Thanks for the info, it certainly was not silly As an aside the 15
degrees is the same as found empirically by Kraus
in the pitch angle of a helical, another example of the inclusion of
the weak force in a system in equilibrium !

My original model was for a dipole tilted 45 degrees. *The following
analysis is for a 35 ft ground mounted monopole with thirty-six 40 ft
radials buried 1" below an average ground of: conductivity 5 mS/m,
and relative permittivity 13. *It is noted that the tilted monopole has
a slight gain opposite to the direction of tilt. *The following comparison
is made in the direction of maximum gain. *The F/B ratio is nominally
0.2 db, and the gain 0.2 db at lower angles. *The measurement was
made on 7.2 MHz, and the input impedance 45 + j 47 ohms.

Take off Angle * * * *Vertical * * * * * *15 deg tilt
(degrees) * * * * * * * Gain (dbi) * * * * * Gain (dbi)
10 * * * * * * * * * * * * * *-2.5 * * * * * * * * * *-2.3
20 * * * * * * * * * * * * * *-0.2 * * * * * * * * * *0
30 * * * * * * * * * * * * * * *0 * * * * * * * * * * * +0.3
40 * * * * * * * * * * * * * * -0.8 * * * * * * * * *-0.3
50 * * * * * * * * * * * * * *-2.3 * * * * * * * * * -1.5
60 * * * * * * * * * * * * * *-4.6 * * * * * * * * * -3.3
70 * * * * * * * * * * * * * *-8.0 * * * * * * * * * -5.9
80 * * * * * * * * * * * * * -14.0 * * * * * * * * *-9.3
90 * * * * * * * * * *Deep null * * * * * * * * * -13.4

CM Monopole with buried radial system.
CE
GW 1 1 0 0 0 0 1 -0.083 0.0026708
GW 37 39 0 1 -0.083 0 40 -0.083 0.0026708
GR 1 36
GS 0 0 0.304800
GE -1 -1 0
GN 2 0 0 0 13.0000 0.0050
FR 0 1 0 0 7.2 0.01
LD 5 0 0 0 5.8001E7
WG monopole_36.NGF
EN

CM 36 Radial Read NGF
CE
GF 0 monopole_36.NGF
GW 73 35 0 9.0587 33.807 0 0 0 0.002671
GS 0 0 0.304800
GE 0 0 0
EX 0 73 35 0 6349.474358 0.00000
LD 5 0 0 0 5.8001E7
RP 0 181 1 1000 -90 270 1.00000 1.00000
EN

73, *Frank

Frank I am not familiar with your programming but the weak force is
just that....weak
It is for that reason the Yagi coupling of elements provides a good
estimate with easy structure.
For long distance accurracy is not a big deal but for measuring and
for medical applications it is.
Art

On Sun, 14 Sep 2008 17:22:37 GMT, "Frank"
wrote:

It is noted that the tilted monopole has
a slight gain opposite to the direction of tilt.

Hi Frank,

The numbers hint of mixed polarization results which would come as no
surprise from tilting which tosses in a horizontal component that was
effectively suppressed by a true vertical.

The hint is the collapse of the overhead null, and the marginal
differences close to the horizon.

73's
Richard Clark, KB7QHC