Antenna physical size
 

It is hanging in the yard right now and obviously is very efficient at
what it does.

You mean it's very efficient at hanging in the yard? :)
Joking aside, I'd be interested in a *NEC file. Is it possible to
model, or is it restricted by the number of segments?

Robert

Antenna physical size
 

On Mar 31, 9:26 pm, wrote:
On Mar 31, 8:52 pm, Jim Lux wrote:

wrote:

Uhhh. actually there ARE laws of physics putting some pretty severe
constraints on it, if not actually forbidding it, if you also accept the
constraint that the material of which you make the antenna has finite
resistance.

Where ease might be defined in terms of being able to be made of
actually realizable materials?

The term 'actually realizable materials' seems to shift it's
definition every time something new is discovered :)



Chu and, later, Harrington said nothing about bandwidth, by the way.
They were more concerned with directivity and size and stored energy
(the latter of which ties to efficiency and bandwidth).

True, I didn't imply that.



Also, even if you created a very small antenna with high efficiency
(e.g. with superconductors), the fields around such an antenna will be
quite intense, so while the antenna may be small, its near field will be
pretty much the same size as the dipole it replaces, so you'll need to
put that tiny antenna way up in the air with a non-conductive, non-lossy
support to get it away from everything else. Finding a feedline might be
a bit of a challenge. One has to be careful when one draws "the
boundary" of the antenna.

Ok, it was my mistake to not clarify 'high efficiency'. By that I
meant 'at the same order of efficiency as normal scale designs'.
I am currenty interested by what I have seen claimed as 'compacted
antennas', which behave similar to normal ones, except their
dimensions are smaller, X-axis wise at least. That those designs do
not perform as well or better than their counterparts is no problem
to me, as long as the figures are in the same ballpark. That would
mean they still are more efficient than previous designs which
attempted to solve the problem of physical dimensions, which is an
advancement in my book. That some other unexpected features as the
broadband factor may appear is only a bonus, because we can achieve
that with full scale antennas too.
To be more specific, I was reffering to such designs that reduce the
scale of antennas in at least one axis:http://adsabs.harvard.edu/abs/2004IT...s.jsp?R=470415
I have seen some of them described as fractal trees, but the
information is relatively scarce. I know research is continuing on
this subject and even found some info at a website somewhere but I
can't remember where. Since you probably know more about them than me,
I would appreciate some guidance here too :)



In practical terms, the size of an antenna isn't just the dimensions of
the metal, but the "keepout" area within which you can't tolerate any
intrusions and still keep the same antenna performance (i.e. a 40m
dipole laying on the ground doesn't work nearly as well as a dipole
suspended 10 feet off the ground)

For that matter, avoiding the breakdown of air might be a problem.
Consider a tesla coil, which is basically a fairly inefficient (in terms
of radiated power for RF input power) small antenna for 100 kHz or so.
The limit on performance for the tesla coil isn't thermal heating of the
coil, but HV breakdown. Even a few hundred watts into a "shoebox" sized
coil will have breakdown problems (and this is fully predicted by Chu's
analysis... it's that "energy stored in the field" problem)

I do not dispute that, however I get a feeling we're talking about
different things.

Best,
Robert

Robert, the Fractal can now be considered obsolete when compared to
mine.
The person who is testing my antenna is a member of this group.
Maybe he will drop a bone regarding this new antenna of mine so I can
have some credability. For years I have been insulted on my findings
and frankly I am getting fed up.People stated that I did not have such
an antenna,
A $5000 stake was put up by an Aussie ( they bet on anything) to say
that he believed me.
Not one of the talking heads were willing to take on the Aussie and
win big.
As I stated they are mostly talking heads and nothing else.
Regards
Art

Antenna physical size
 

On Mar 31, 9:39 pm, wrote:
It is hanging in the yard right now and obviously is very efficient at
what it does.

You mean it's very efficient at hanging in the yard? :)
Joking aside, I'd be interested in a *NEC file. Is it possible to
model, or is it restricted by the number of segments?

Robert

Restricted by the number of segments but I have tested enough of the
diifferent designs
to know what I am talking aboutand only a few can be programed but
with limited segments
it can only provide guidance. MAYBE one day I will supply the patent
request number
I received last year as well as the following patent number but the
number of insults
have ruled that possibility out. The person who is testing it never
insulted me and
wanted badly to be on the inside of this new antenna. Sooner or later
the PTO will provide all.
The hula hoop was just a design for checking, The one I have now is on
a tip and turn set up
for the top of my tower for use with a mesh dish for 160 and all other
frequencies. I want to change the polarity
in situ !.
You never can stop learning once you get off the normal path and
penetrate the underbrush.
Suddenly the brush is behind and a clear valley bathed in sun light
appears and you have little time
to fully explore
There are many different versions of this antenna primarily to get a
complete range of impedences
for use as well as determining tilt angle e.t.c.
Regards
Art

Antenna physical size
 

Cecil Moore wrote:
Richard Clark wrote:
But you don't know how, and have never seen one either.

Dear Richard - some people contribute to human knowledge
through their optimism regarding things to come that are
presently out of reach. Some people would prefer that we
live forever in the dark ages. Which one are you?


Never forget that we need all types, Cecil. Imagine a world where
complete suspension of disbelief made all theories equal.


- 73 de Mike N3LI -

Antenna physical size
 

Antenna physical size
 

On Mar 31, 7:52 pm, Jim Lux wrote:
wrote:
I find this topic very interesting, including the mandrill part :)

We all want to have small, broadband, eficient antennas. I believe Art
is right in his original post, today we can have all these
characteristics in the same package. There is no law of physics
forbidding that.

Uhhh. actually there ARE laws of physics putting some pretty severe
constraints on it, if not actually forbidding it, if you also accept the
constraint that the material of which you make the antenna has finite
resistance.

Through advances in computation power we can achieve

today in months what took decades in the past and there is much
research directed at these kinds of new antennas. Eventually
everyone will be able to choose and model his own antenna based on the
characteristics one wants, but without the cumbersome dimensions,
without significant bandwith limitations, without major efficiency
compromises. I believe the tradeoff (for it has to exist one) will be
ease of manufacturing.

Where ease might be defined in terms of being able to be made of
actually realizable materials?



Incidentally these new antennas have a lot to do with what Art
defines as equilibrium although I don't think he has a clear enough
definition. But it's all related to patterns, patterns which can be
found everywhere in nature an which can be expressed almost entirely
through matemathical formulas. Scaling of antennas is clearly
possible, despite of what the Chu-Harrington limit states ( or to be
fair, by applying them in a new way ).

Chu and, later, Harrington said nothing about bandwidth, by the way.
They were more concerned with directivity and size and stored energy
(the latter of which ties to efficiency and bandwidth).

Also, even if you created a very small antenna with high efficiency
(e.g. with superconductors), the fields around such an antenna will be
quite intense, so while the antenna may be small, its near field will be
pretty much the same size as the dipole it replaces, so you'll need to
put that tiny antenna way up in the air with a non-conductive, non-lossy
support to get it away from everything else. Finding a feedline might be
a bit of a challenge. One has to be careful when one draws "the
boundary" of the antenna.

In practical terms, the size of an antenna isn't just the dimensions of
the metal, but the "keepout" area within which you can't tolerate any
intrusions and still keep the same antenna performance (i.e. a 40m
dipole laying on the ground doesn't work nearly as well as a dipole
suspended 10 feet off the ground)

For that matter, avoiding the breakdown of air might be a problem.
Consider a tesla coil, which is basically a fairly inefficient (in terms
of radiated power for RF input power) small antenna for 100 kHz or so.
The limit on performance for the tesla coil isn't thermal heating of the
coil, but HV breakdown. Even a few hundred watts into a "shoebox" sized
coil will have breakdown problems (and this is fully predicted by Chu's
analysis... it's that "energy stored in the field" problem)

I eagerly await the day when the 80 meter dipole will be replace by a
small device the size of a shoe box ( although it might be a bit
larger in the beginning :) ).

Regards,
Robert

When the air breaks down around an antenna it is because the antenna
is not in a state of equilibrium. When a dipole is replaced by a quad
ala
a series circuit is replaced by a tank circuit it clearly shows that
the latter
is more efficient.This was firmly proven in Quito.Maximum radiation
efficiency requires equilibrium. Period
Art

Antenna physical size
 

On Mar 31, 9:39 pm, wrote:
It is hanging in the yard right now and obviously is very efficient at
what it does.

You mean it's very efficient at hanging in the yard? :)
Joking aside, I'd be interested in a *NEC file. Is it possible to
model, or is it restricted by the number of segments?

Robert

Let me clarify my answer.
The natural resonance resistance can exceed 1000 ohms
thought with the same design the resistance can be lowered
at the expense of bandwidth. These design forms can be easily
modelled with or without a dish reflector. I introduced twisted
wire into the design to overcome the reduced bandwidth of
the other design to bring the resistance down to the 50 to
100 ohm mark for easy match to existing components.
Since the impedance resistance is drastically lowered when
using the standard design on the computor I am inclined only
to use the computor as a guide in that instance. The dish
modelled consist of parallel elements which obviously would
be a bear to tilt so many inaccuracies are built in except in
the case of the assembly being tilted which I am presently
researching.
Art

Antenna physical size
 

On Apr 1, 9:18 am, Art Unwin wrote:


When the air breaks down around an antenna it is because the antenna
is not in a state of equilibrium. When a dipole is replaced by a quad
ala
a series circuit is replaced by a tank circuit it clearly shows that
the latter
is more efficient.This was firmly proven in Quito.Maximum radiation
efficiency requires equilibrium. Period
Art

If you don't quit spewing all this blatant horse crap, I will be going
into
talking head mode again.
BTW, I'm younger than you are. So your claims of age affecting
vulnerability to the effects of constant bafflegab and horse caca
will
tested at great lengths in such an endeavor.
The change of the fabled antenna at HCJB had nothing to do with
efficiency. Period.

Antenna physical size
 

On Apr 1, 12:57 pm, wrote:
On Apr 1, 9:18 am, Art Unwin wrote:



When the air breaks down around an antenna it is because the antenna
is not in a state of equilibrium. When a dipole is replaced by a quad
ala
a series circuit is replaced by a tank circuit it clearly shows that
the latter
is more efficient.This was firmly proven in Quito.Maximum radiation
efficiency requires equilibrium. Period
Art

If you don't quit spewing all this blatant horse crap, I will be going
into
talking head mode again.
BTW, I'm younger than you are. So your claims of age affecting
vulnerability to the effects of constant bafflegab and horse caca
will
tested at great lengths in such an endeavor.
The change of the fabled antenna at HCJB had nothing to do with
efficiency. Period.

You my friend are a good example of what a redneck thinks.
In the past you have bragged about your lack of schooling
spouting about the times you didn't go to school. Now you have a
license
to operate a radio where you can excercise your freedom of speech at
will.
Unfortunately, as soon as you start vibrating you vocal cords you
instantly
reveal who and what you are. This is of immense inportance to the
rest of us
when considering whether to use our precious time to your utterings.
Go ahead and be a talking head but you will find that your audio lacks
propagation
in the subject of antennas
Have a happy day and be nice to those around you. You will never know
when
that last day of yours comes around despite your youthful age.
Art Unwin

Antenna physical size
 

On Apr 1, 12:32 pm, Art Unwin wrote:
On Apr 1, 12:57 pm, wrote:



On Apr 1, 9:18 am, Art Unwin wrote:

When the air breaks down around an antenna it is because the antenna
is not in a state of equilibrium. When a dipole is replaced by a quad
ala
a series circuit is replaced by a tank circuit it clearly shows that
the latter
is more efficient.This was firmly proven in Quito.Maximum radiation
efficiency requires equilibrium. Period
Art

If you don't quit spewing all this blatant horse crap, I will be going
into
talking head mode again.
BTW, I'm younger than you are. So your claims of age affecting
vulnerability to the effects of constant bafflegab and horse caca
will
tested at great lengths in such an endeavor.
The change of the fabled antenna at HCJB had nothing to do with
efficiency. Period.

You my friend are a good example of what a redneck thinks.
In the past you have bragged about your lack of schooling
spouting about the times you didn't go to school. Now you have a
license
to operate a radio where you can excercise your freedom of speech at
will.
Unfortunately, as soon as you start vibrating you vocal cords you
instantly
reveal who and what you are. This is of immense inportance to the
rest of us
when considering whether to use our precious time to your utterings.
Go ahead and be a talking head but you will find that your audio lacks
propagation
in the subject of antennas
Have a happy day and be nice to those around you. You will never know
when
that last day of yours comes around despite your youthful age.
Art Unwin

Prior Art... I have never "bragged" about not going to school.
I was expelled from school. Which means I really didn't have a
whole lot of choice in the matter past that stage.
But in the general scheme of things this means little, as most
schools don't teach antenna theory unless it's a specific college
course.
You have never heard my vocal cords vibrate, as you have never
talked to me. I doubt if you have even heard me on the air.

Being you are so highly educated, why is your spelling
so bad?
Seems to me you went to school, but either slept through
it, or had other things to think about.
In any case, you are the last horses ass that should be
braying about my education.
I educate myself, and have plenty of books laying around.
It's funny, I am self educated and oft speak about antennas,
but few people have any problems with what I write about.
If they do, it's usually some fairly minor detail.
You on the other hand, claim to be well educated, but
almost everything you spout is challenged as bafflegab,
pure untruth, or just plain horse crap.
What is wrong with this picture?
Prior Art, you make me feel gifted, being I seem to be
ahead of you as far as antenna theory, and I didn't
take *any* scholarly courses for it.
I think you should learn to write and spell a little better
if you are going to whine about other peoples lack of
education. Your "Queens English" is a mess.
What is your excuse for this problem?
I absolutely hated English when in school, yet I seem
to be doing a bit better writing it than you, even with my
sub par education. At least I have an excuse though.
Again, you make me feel downright gifted to be on par
with such a highly educated man such as yourself. :/
MK