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Old July 5th 08, 02:21 PM posted to rec.radio.amateur.antenna
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Posts: 440
Default Radiation and dummy loads

"Art Unwin" wrote
On Jul 4, 5:29 pm, rick frazier wrote:
Not sure where you get the swr repetitive over a band of frequencies
stuff, (perhaps I don't read enough of the group messages) but to reply
relative to dummy loads in general....


This comes from the radiator listed on my page
unwinantennas.com/

_______________________

Art -

The most important measure of an antenna is the amount of field intensity it
can produce at a given distance in a given direction, per watt of applied
r-f power. So far you have written nothing specific about this for the
"Unwin" antenna.

Note that a transmission line feeding a 20 dB series attenuator attached to
the input of a 100% efficient antenna will show very high return loss to the
r-f source ( 40 dB plus the twice the cable loss). But that antenna system
will radiate little of the available EM energy, nonetheless.

Could you please comment on the measured or at least the calculated
RADIATION CHARACTERISTICS of your antenna, compared to a matched 1/2-wave
dipole at that frequency (or an isotropic radiator), and tell us how you
arrived at them?

If you can do that, and your results can be scientifically duplicated by
others, you will have removed the source of a lot of the skepticism you read
here and in your similar threads on eHam.net.

Otherwise it will be "more of the same," which (let us hope) is or should
not be your goal.

RF

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Old July 5th 08, 02:46 PM posted to rec.radio.amateur.antenna
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Posts: 1,339
Default Radiation and dummy loads

On Jul 5, 8:21 am, "Richard Fry" wrote:
"Art Unwin" wrote On Jul 4, 5:29 pm, rick frazier wrote:
Not sure where you get the swr repetitive over a band of frequencies
stuff, (perhaps I don't read enough of the group messages) but to reply
relative to dummy loads in general....


This comes from the radiator listed on my page
unwinantennas.com/


_______________________

Art -

The most important measure of an antenna is the amount of field intensity it
can produce at a given distance in a given direction, per watt of applied
r-f power. So far you have written nothing specific about this for the
"Unwin" antenna.

Note that a transmission line feeding a 20 dB series attenuator attached to
the input of a 100% efficient antenna will show very high return loss to the
r-f source ( 40 dB plus the twice the cable loss). But that antenna system
will radiate little of the available EM energy, nonetheless.

Could you please comment on the measured or at least the calculated
RADIATION CHARACTERISTICS of your antenna, compared to a matched 1/2-wave
dipole at that frequency (or an isotropic radiator), and tell us how you
arrived at them?

If you can do that, and your results can be scientifically duplicated by
others, you will have removed the source of a lot of the skepticism you read
here and in your similar threads on eHam.net.

Otherwise it will be "more of the same," which (let us hope) is or should
not be your goal.

RF


No.More of the same is not my goal nor is it to respond to every
request.
The mathematision or doctorrate type can do it solely by mathematics.
The computor program is built on those mathematics. and a antenna
program
will ALWAYs produce radiators in equilibrium which means at an angle.
Even without
a optimiser you can do it on Eznec but it would be laborious but it
can be done.
People are enamoured with the Yagi so thay always insert planar type
figures thus the
program which is designed around equilibrium. If the goal is small
efficient radiators then
equilibrium must be present starting with a full wavelength that can
then be placed in a small volume.
It is the smaller efficient radiators and arrays that I have pursued
since radiation per unit length is solely a measure
that correlates with resistivity and it is that where my conclusions
lie. Gain itself is a whole different matter
cannot show it's worth
  #3   Report Post  
Old July 5th 08, 05:47 PM posted to rec.radio.amateur.antenna
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First recorded activity by RadioBanter: Jul 2006
Posts: 797
Default Radiation and dummy loads


"Art Unwin" wrote in message
...
On Jul 5, 8:21 am, "Richard Fry" wrote:
"Art Unwin" wrote On Jul 4, 5:29 pm, rick frazier wrote:
Not sure where you get the swr repetitive over a band of frequencies
stuff, (perhaps I don't read enough of the group messages) but to
reply
relative to dummy loads in general....


This comes from the radiator listed on my page
unwinantennas.com/


_______________________

Art -

The most important measure of an antenna is the amount of field intensity
it
can produce at a given distance in a given direction, per watt of applied
r-f power. So far you have written nothing specific about this for the
"Unwin" antenna.

Note that a transmission line feeding a 20 dB series attenuator attached
to
the input of a 100% efficient antenna will show very high return loss to
the
r-f source ( 40 dB plus the twice the cable loss). But that antenna
system
will radiate little of the available EM energy, nonetheless.

Could you please comment on the measured or at least the calculated
RADIATION CHARACTERISTICS of your antenna, compared to a matched 1/2-wave
dipole at that frequency (or an isotropic radiator), and tell us how you
arrived at them?

If you can do that, and your results can be scientifically duplicated by
others, you will have removed the source of a lot of the skepticism you
read
here and in your similar threads on eHam.net.

Otherwise it will be "more of the same," which (let us hope) is or should
not be your goal.

RF


No.More of the same is not my goal nor is it to respond to every
request.
The mathematision or doctorrate type can do it solely by mathematics.
The computor program is built on those mathematics. and a antenna
program
will ALWAYs produce radiators in equilibrium which means at an angle.
Even without
a optimiser you can do it on Eznec but it would be laborious but it
can be done.
People are enamoured with the Yagi so thay always insert planar type
figures thus the
program which is designed around equilibrium. If the goal is small
efficient radiators then
equilibrium must be present starting with a full wavelength that can
then be placed in a small volume.
It is the smaller efficient radiators and arrays that I have pursued
since radiation per unit length is solely a measure
that correlates with resistivity and it is that where my conclusions
lie. Gain itself is a whole different matter
cannot show it's worth


in other words, he hasn't, he won't, and he doesn't care... therefore, more
of the same handwaving and meaningless bafflegab. he doesn't have the math
background to present his theory in any kind of a coherent form, nor of
course could he ever measure his neutrino/carbon vortex crud because it
doesn't exist, so he keeps going back to the same old crap... its not even
funny any more, just sad.


  #4   Report Post  
Old July 5th 08, 06:27 PM posted to rec.radio.amateur.antenna
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First recorded activity by RadioBanter: Mar 2008
Posts: 1,339
Default Radiation and dummy loads

On Jul 5, 11:47 am, "Dave" wrote:
"Art Unwin" wrote in message

...



On Jul 5, 8:21 am, "Richard Fry" wrote:
"Art Unwin" wrote On Jul 4, 5:29 pm, rick frazier wrote:
Not sure where you get the swr repetitive over a band of frequencies
stuff, (perhaps I don't read enough of the group messages) but to
reply
relative to dummy loads in general....


This comes from the radiator listed on my page
unwinantennas.com/


_______________________


Art -


The most important measure of an antenna is the amount of field intensity
it
can produce at a given distance in a given direction, per watt of applied
r-f power. So far you have written nothing specific about this for the
"Unwin" antenna.


Note that a transmission line feeding a 20 dB series attenuator attached
to
the input of a 100% efficient antenna will show very high return loss to
the
r-f source ( 40 dB plus the twice the cable loss). But that antenna
system
will radiate little of the available EM energy, nonetheless.


Could you please comment on the measured or at least the calculated
RADIATION CHARACTERISTICS of your antenna, compared to a matched 1/2-wave
dipole at that frequency (or an isotropic radiator), and tell us how you
arrived at them?


If you can do that, and your results can be scientifically duplicated by
others, you will have removed the source of a lot of the skepticism you
read
here and in your similar threads on eHam.net.


Otherwise it will be "more of the same," which (let us hope) is or should
not be your goal.


RF


No.More of the same is not my goal nor is it to respond to every
request.
The mathematision or doctorrate type can do it solely by mathematics.
The computor program is built on those mathematics. and a antenna
program
will ALWAYs produce radiators in equilibrium which means at an angle.
Even without
a optimiser you can do it on Eznec but it would be laborious but it
can be done.
People are enamoured with the Yagi so thay always insert planar type
figures thus the
program which is designed around equilibrium. If the goal is small
efficient radiators then
equilibrium must be present starting with a full wavelength that can
then be placed in a small volume.
It is the smaller efficient radiators and arrays that I have pursued
since radiation per unit length is solely a measure
that correlates with resistivity and it is that where my conclusions
lie. Gain itself is a whole different matter
cannot show it's worth


in other words, he hasn't, he won't, and he doesn't care... therefore, more
of the same handwaving and meaningless bafflegab. he doesn't have the math
background to present his theory in any kind of a coherent form, nor of
course could he ever measure his neutrino/carbon vortex crud because it
doesn't exist, so he keeps going back to the same old crap... its not even
funny any more, just sad.


David,
at this stage in life it would very difficult for me to go thru the
math from the start
in the exercise of adding a a radiator and a time varying field to a
Gaussian field
to show it is the same asMaxwell equation, very few of us are. But
when you come across a theorem
that makes sense to you it is gravy added when a mathematician comes
along to supply the mathematics
which you can follow in part. Then when antenna computor programs
supply the ingredients of such an analysis
which proves the same you have to get excited. When you then apply
what is revealed in such a trail and succeed in making a smaller
antenna that anybody has made you stop questioning what you have
found. As an aside, where do you view the atributes of an antenna with
near constant SWR reponse would find most use. I know most will jump
to dummy load but this I ask in serious form.
  #5   Report Post  
Old July 5th 08, 07:32 PM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 797
Default Radiation and dummy loads


"Art Unwin" wrote in message
...
On Jul 5, 11:47 am, "Dave" wrote:
"Art Unwin" wrote in message

...



On Jul 5, 8:21 am, "Richard Fry" wrote:
"Art Unwin" wrote On Jul 4, 5:29 pm, rick frazier wrote:
Not sure where you get the swr repetitive over a band of
frequencies
stuff, (perhaps I don't read enough of the group messages) but to
reply
relative to dummy loads in general....


This comes from the radiator listed on my page
unwinantennas.com/


_______________________


Art -


The most important measure of an antenna is the amount of field
intensity
it
can produce at a given distance in a given direction, per watt of
applied
r-f power. So far you have written nothing specific about this for
the
"Unwin" antenna.


Note that a transmission line feeding a 20 dB series attenuator
attached
to
the input of a 100% efficient antenna will show very high return loss
to
the
r-f source ( 40 dB plus the twice the cable loss). But that antenna
system
will radiate little of the available EM energy, nonetheless.


Could you please comment on the measured or at least the calculated
RADIATION CHARACTERISTICS of your antenna, compared to a matched
1/2-wave
dipole at that frequency (or an isotropic radiator), and tell us how
you
arrived at them?


If you can do that, and your results can be scientifically duplicated
by
others, you will have removed the source of a lot of the skepticism
you
read
here and in your similar threads on eHam.net.


Otherwise it will be "more of the same," which (let us hope) is or
should
not be your goal.


RF


No.More of the same is not my goal nor is it to respond to every
request.
The mathematision or doctorrate type can do it solely by mathematics.
The computor program is built on those mathematics. and a antenna
program
will ALWAYs produce radiators in equilibrium which means at an angle.
Even without
a optimiser you can do it on Eznec but it would be laborious but it
can be done.
People are enamoured with the Yagi so thay always insert planar type
figures thus the
program which is designed around equilibrium. If the goal is small
efficient radiators then
equilibrium must be present starting with a full wavelength that can
then be placed in a small volume.
It is the smaller efficient radiators and arrays that I have pursued
since radiation per unit length is solely a measure
that correlates with resistivity and it is that where my conclusions
lie. Gain itself is a whole different matter
cannot show it's worth


in other words, he hasn't, he won't, and he doesn't care... therefore,
more
of the same handwaving and meaningless bafflegab. he doesn't have the
math
background to present his theory in any kind of a coherent form, nor of
course could he ever measure his neutrino/carbon vortex crud because it
doesn't exist, so he keeps going back to the same old crap... its not
even
funny any more, just sad.


David,
at this stage in life it would very difficult for me to go thru the
math from the start
in the exercise of adding a a radiator and a time varying field to a
Gaussian field
to show it is the same asMaxwell equation, very few of us are. But
when you come across a theorem
that makes sense to you it is gravy added when a mathematician comes
along to supply the mathematics
which you can follow in part. Then when antenna computor programs
supply the ingredients of such an analysis
which proves the same you have to get excited. When you then apply
what is revealed in such a trail and succeed in making a smaller
antenna that anybody has made you stop questioning what you have
found. As an aside, where do you view the atributes of an antenna with
near constant SWR reponse would find most use. I know most will jump
to dummy load but this I ask in serious form.


I already gave you the quote that shows that Gauss's Law is part of
Maxwell's equations already, you need no math for that. and since all the
antenna design programs are based on Maxwell's equations they of course
comply with Gauss's law... nothing exciting there.

the only use for a constant swr is to keep modern transceivers, that don't
have a tuner, happy. swr has no correlation to performance of an antenna as
far as gain or f/b or takeoff angle, things that are important to antenna
design. i can take any antenna and give it a flat swr, there used to be a
tuner on the market that did just that, until the league lab x-rayed it and
found it was nothing but a dummy load potted in epoxy. the funny thing is,
people liked it because it did exactly as it claimed, gave a perfect match
across a wide frequency range... they didn't care that it turned a good
percentage of their power into heat. so air cooled dummy loads as antennas
can work, as long as you don't have anything better to compare it to... but
I do, so I don't want one.






  #6   Report Post  
Old July 5th 08, 08:25 PM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Mar 2008
Posts: 1,339
Default Radiation and dummy loads

On Jul 5, 1:32 pm, "Dave" wrote:
"Art Unwin" wrote in message

...



On Jul 5, 11:47 am, "Dave" wrote:
"Art Unwin" wrote in message


...


On Jul 5, 8:21 am, "Richard Fry" wrote:
"Art Unwin" wrote On Jul 4, 5:29 pm, rick frazier wrote:
Not sure where you get the swr repetitive over a band of
frequencies
stuff, (perhaps I don't read enough of the group messages) but to
reply
relative to dummy loads in general....


This comes from the radiator listed on my page
unwinantennas.com/


_______________________


Art -


The most important measure of an antenna is the amount of field
intensity
it
can produce at a given distance in a given direction, per watt of
applied
r-f power. So far you have written nothing specific about this for
the
"Unwin" antenna.


Note that a transmission line feeding a 20 dB series attenuator
attached
to
the input of a 100% efficient antenna will show very high return loss
to
the
r-f source ( 40 dB plus the twice the cable loss). But that antenna
system
will radiate little of the available EM energy, nonetheless.


Could you please comment on the measured or at least the calculated
RADIATION CHARACTERISTICS of your antenna, compared to a matched
1/2-wave
dipole at that frequency (or an isotropic radiator), and tell us how
you
arrived at them?


If you can do that, and your results can be scientifically duplicated
by
others, you will have removed the source of a lot of the skepticism
you
read
here and in your similar threads on eHam.net.


Otherwise it will be "more of the same," which (let us hope) is or
should
not be your goal.


RF


No.More of the same is not my goal nor is it to respond to every
request.
The mathematision or doctorrate type can do it solely by mathematics.
The computor program is built on those mathematics. and a antenna
program
will ALWAYs produce radiators in equilibrium which means at an angle.
Even without
a optimiser you can do it on Eznec but it would be laborious but it
can be done.
People are enamoured with the Yagi so thay always insert planar type
figures thus the
program which is designed around equilibrium. If the goal is small
efficient radiators then
equilibrium must be present starting with a full wavelength that can
then be placed in a small volume.
It is the smaller efficient radiators and arrays that I have pursued
since radiation per unit length is solely a measure
that correlates with resistivity and it is that where my conclusions
lie. Gain itself is a whole different matter
cannot show it's worth


in other words, he hasn't, he won't, and he doesn't care... therefore,
more
of the same handwaving and meaningless bafflegab. he doesn't have the
math
background to present his theory in any kind of a coherent form, nor of
course could he ever measure his neutrino/carbon vortex crud because it
doesn't exist, so he keeps going back to the same old crap... its not
even
funny any more, just sad.


David,
at this stage in life it would very difficult for me to go thru the
math from the start
in the exercise of adding a a radiator and a time varying field to a
Gaussian field
to show it is the same asMaxwell equation, very few of us are. But
when you come across a theorem
that makes sense to you it is gravy added when a mathematician comes
along to supply the mathematics
which you can follow in part. Then when antenna computor programs
supply the ingredients of such an analysis
which proves the same you have to get excited. When you then apply
what is revealed in such a trail and succeed in making a smaller
antenna that anybody has made you stop questioning what you have
found. As an aside, where do you view the atributes of an antenna with
near constant SWR reponse would find most use. I know most will jump
to dummy load but this I ask in serious form.


I already gave you the quote that shows that Gauss's Law is part of
Maxwell's equations already, you need no math for that. and since all the
antenna design programs are based on Maxwell's equations they of course
comply with Gauss's law... nothing exciting there.

the only use for a constant swr is to keep modern transceivers, that don't
have a tuner, happy. swr has no correlation to performance of an antenna as
far as gain or f/b or takeoff angle, things that are important to antenna
design. i can take any antenna and give it a flat swr, there used to be a
tuner on the market that did just that, until the league lab x-rayed it and
found it was nothing but a dummy load potted in epoxy. the funny thing is,
people liked it because it did exactly as it claimed, gave a perfect match
across a wide frequency range... they didn't care that it turned a good
percentage of their power into heat. so air cooled dummy loads as antennas
can work, as long as you don't have anything better to compare it to... but
I do, so I don't want one.


David ,Gauss did a lot of work in his life time for which he is
recognised.
Are you saying that the "Gaussian law of static" was a prime mover of
Maxwells laws.
If this is so why does not Maxwells laws provide the role of particles
in radiation?
From my view point Gauss's contribution was supplied in other ways
that did not include the statics law but then I look forward to you
showing me where I am wrong
  #7   Report Post  
Old July 5th 08, 10:15 PM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 797
Default Radiation and dummy loads

"Art Unwin" wrote in message
...
On Jul 5, 1:32 pm, "Dave" wrote:
"Art Unwin" wrote in message

...



On Jul 5, 11:47 am, "Dave" wrote:
"Art Unwin" wrote in message


...


On Jul 5, 8:21 am, "Richard Fry" wrote:
"Art Unwin" wrote On Jul 4, 5:29 pm, rick frazier wrote:
Not sure where you get the swr repetitive over a band of
frequencies
stuff, (perhaps I don't read enough of the group messages) but
to
reply
relative to dummy loads in general....


This comes from the radiator listed on my page
unwinantennas.com/


_______________________


Art -


The most important measure of an antenna is the amount of field
intensity
it
can produce at a given distance in a given direction, per watt of
applied
r-f power. So far you have written nothing specific about this for
the
"Unwin" antenna.


Note that a transmission line feeding a 20 dB series attenuator
attached
to
the input of a 100% efficient antenna will show very high return
loss
to
the
r-f source ( 40 dB plus the twice the cable loss). But that
antenna
system
will radiate little of the available EM energy, nonetheless.


Could you please comment on the measured or at least the calculated
RADIATION CHARACTERISTICS of your antenna, compared to a matched
1/2-wave
dipole at that frequency (or an isotropic radiator), and tell us
how
you
arrived at them?


If you can do that, and your results can be scientifically
duplicated
by
others, you will have removed the source of a lot of the skepticism
you
read
here and in your similar threads on eHam.net.


Otherwise it will be "more of the same," which (let us hope) is or
should
not be your goal.


RF


No.More of the same is not my goal nor is it to respond to every
request.
The mathematision or doctorrate type can do it solely by
mathematics.
The computor program is built on those mathematics. and a antenna
program
will ALWAYs produce radiators in equilibrium which means at an
angle.
Even without
a optimiser you can do it on Eznec but it would be laborious but it
can be done.
People are enamoured with the Yagi so thay always insert planar type
figures thus the
program which is designed around equilibrium. If the goal is small
efficient radiators then
equilibrium must be present starting with a full wavelength that can
then be placed in a small volume.
It is the smaller efficient radiators and arrays that I have pursued
since radiation per unit length is solely a measure
that correlates with resistivity and it is that where my conclusions
lie. Gain itself is a whole different matter
cannot show it's worth


in other words, he hasn't, he won't, and he doesn't care... therefore,
more
of the same handwaving and meaningless bafflegab. he doesn't have the
math
background to present his theory in any kind of a coherent form, nor
of
course could he ever measure his neutrino/carbon vortex crud because
it
doesn't exist, so he keeps going back to the same old crap... its not
even
funny any more, just sad.


David,
at this stage in life it would very difficult for me to go thru the
math from the start
in the exercise of adding a a radiator and a time varying field to a
Gaussian field
to show it is the same asMaxwell equation, very few of us are. But
when you come across a theorem
that makes sense to you it is gravy added when a mathematician comes
along to supply the mathematics
which you can follow in part. Then when antenna computor programs
supply the ingredients of such an analysis
which proves the same you have to get excited. When you then apply
what is revealed in such a trail and succeed in making a smaller
antenna that anybody has made you stop questioning what you have
found. As an aside, where do you view the atributes of an antenna with
near constant SWR reponse would find most use. I know most will jump
to dummy load but this I ask in serious form.


I already gave you the quote that shows that Gauss's Law is part of
Maxwell's equations already, you need no math for that. and since all
the
antenna design programs are based on Maxwell's equations they of course
comply with Gauss's law... nothing exciting there.

the only use for a constant swr is to keep modern transceivers, that
don't
have a tuner, happy. swr has no correlation to performance of an antenna
as
far as gain or f/b or takeoff angle, things that are important to antenna
design. i can take any antenna and give it a flat swr, there used to be
a
tuner on the market that did just that, until the league lab x-rayed it
and
found it was nothing but a dummy load potted in epoxy. the funny thing
is,
people liked it because it did exactly as it claimed, gave a perfect
match
across a wide frequency range... they didn't care that it turned a good
percentage of their power into heat. so air cooled dummy loads as
antennas
can work, as long as you don't have anything better to compare it to...
but
I do, so I don't want one.


David ,Gauss did a lot of work in his life time for which he is
recognised.
Are you saying that the "Gaussian law of static" was a prime mover of
Maxwells laws.
If this is so why does not Maxwells laws provide the role of particles
in radiation?
From my view point Gauss's contribution was supplied in other ways
that did not include the statics law but then I look forward to you
showing me where I am wrong


well, your point of view is wrong.


  #8   Report Post  
Old July 6th 08, 05:30 PM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 588
Default Radiation and dummy loads

Art wrote:
"If this is so, why do not Maxwell`s laws provide the role of particles
in radiation?"

Maxwell`s equarions adequately describe electrical behavior without
resort to particles.

Art should read "Radio-Electronic Transmission Fundamentals" by B.
Whitfield Griffith, Jr. Its first chapter is: "A Brief History of
Electrical Knowledge". Maxwell`s equations are covered in Chapter 38,
"The Mechanism of Radiation".

On page 9, Griffirh wrote:
"Maxwell studied deeply the equations he had written and noted that they
were similar in form to equations which were used to express the motion
of waves in water. This made it clear to him that electromagnetic waves
could exist, and he was able to calculate the speed at which they would
travel.

Best regards, Richard Harrison, KB5WZI

  #9   Report Post  
Old July 6th 08, 07:52 PM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Oct 2007
Posts: 149
Default Radiation and dummy loads

Art Unwin wrote:
On Jul 5, 11:47 am, "Dave" wrote:


David,
at this stage in life it would very difficult for me to go thru the
math from the start
in the exercise of adding a a radiator and a time varying field to a
Gaussian field
to show it is the same asMaxwell equation, very few of us are.


At this stage of my life, Arthur, it has become very difficult for me to
take you seriously.

Dave K8MN
  #10   Report Post  
Old July 5th 08, 07:10 PM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 588
Default Radiation and dummy loads

Art wrote:
"The computer program is built on those mathematics, and an antenna
program will ALLWAYS produce radiators in equalibrium which means at an
angle."

Arnold B. Bailey disagrees in "TV and Other Receiving Antennas". On page
367 he writes:
"The directional action of a rod antenna best can be analyzed by
considering the rod as consisting of many tiny sections, connected
together to form a metallic circuit. A typical small segment X - X is
shown in Fig. 7-28 B; its position in a half-wave center-fed antenna is
indicated in part (A) of the figure. Each tiny section may be taken
sufficiently short compared to a wavelength so that the electromagnetic
wave acts practically instantaneously throughout one section, and hence
induces a substantially uniform current in that section. Such a short
antenna segment has a simple directional response pattern, indicated in
Fig. 7-28B, which is basic for all directivity calculations, since all
antenns may be considered to be made up of these tiny segments. This
fundamental response pattern varies as the cosine of the angle (which we
shall call theta) between the direction of the incoming wave and the
perpendicular through the center of the segment X - X, as indicated in
part (B) of the figure. If E stands for the value of the field intensity
(strength of the electric vector), then we can characterize the
directional response by the relation Ecos theta, which gives us the
relative magnitude of E for any wave direction relative to the antenna."

You probably have seen the figure-eight pattern of a dipole antenna and
are already aware that maximum response is broadside to the antenna at
its center. If the antenna is tilted away from the perpendicular its
response is diminished. Other antennas have a similar response as all
are made up of elemental segments.

Best regards, Richard Harrison, KB5WZI



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