I have searched quite a bit for evidence that states that performance
of antennas can be rated by it's size. Formulas do not refere to
radiator size or volume
and aparture is referenced to gain. I understand that sort of thinking
based on Yagi design
but the idea that all small radiators are inefficient is rather
ludicrouse. My work, based on
the sciences of the masters, show that a efficient radiator can be any
size,shape and
configuration as long as it
is in equilibrium . Period
No where can I find reference to "size" in what the masters state
Regards
Art

wrote:
I have searched quite a bit for evidence that states that performance
of antennas can be rated by it's size. Formulas do not refere to
radiator size or volume
and aparture is referenced to gain. I understand that sort of thinking
based on Yagi design
but the idea that all small radiators are inefficient is rather
ludicrouse. My work, based on
the sciences of the masters, show that a efficient radiator can be any
size,shape and
configuration as long as it
is in equilibrium . Period
No where can I find reference to "size" in what the masters state
Regards
Art

The work by Chu (Journal of Applied Physics, p1163, v19, Dec 1948) and
subsequently by Harrington (IEEE Trans Ant & Prop, V18#6, Nov 1965,
p896) , Thiele (IEEE Trans on Ant and Prop, v51, #6, June 2003, p1263)
and later others, discusses fundamental limits on performance. Watch
out, though, for the assumptions in the constraints (e.g. whether the
device attached to the feedpoint is reciprocal), and, of course, where
the boundary of the system is.

Watch out also for the definition of "Q", which in this context is the
ratio of stored to disspated/radiated energy, not the ratio of center
frequency/bandwidth.


In short, there is a tradeoff between Q, directivity, and size. And,
because high Q implies high stored energy, for physically realizable
antennas with loss, efficiency is in the mix too.





Googling "chu harrington limit" often turns up useful stuff.

On Mar 7, 11:46 am, Jim Lux wrote:
wrote:
I have searched quite a bit for evidence that states that performance
of antennas can be rated by it's size. Formulas do not refere to
radiator size or volume
and aparture is referenced to gain. I understand that sort of thinking
based on Yagi design
but the idea that all small radiators are inefficient is rather
ludicrouse. My work, based on
the sciences of the masters, show that a efficient radiator can be any
size,shape and
configuration as long as it
is in equilibrium . Period
No where can I find reference to "size" in what the masters state
Regards
Art

The work by Chu (Journal of Applied Physics, p1163, v19, Dec 1948) and
subsequently by Harrington (IEEE Trans Ant & Prop, V18#6, Nov 1965,
p896) , Thiele (IEEE Trans on Ant and Prop, v51, #6, June 2003, p1263)
and later others, discusses fundamental limits on performance. Watch
out, though, for the assumptions in the constraints (e.g. whether the
device attached to the feedpoint is reciprocal), and, of course, where
the boundary of the system is.

Watch out also for the definition of "Q", which in this context is the
ratio of stored to disspated/radiated energy, not the ratio of center
frequency/bandwidth.

In short, there is a tradeoff between Q, directivity, and size. And,
because high Q implies high stored energy, for physically realizable
antennas with loss, efficiency is in the mix too.

Googling "chu harrington limit" often turns up useful stuff.

Googled Chu harrington and find that his work is basically empirical
around known arrangements.
When he brought the question of Q into the picture he made the
statement that small antennas
are usually of a low impedance which is correct empirically with
respect to existing designs but it is not exclusive
when dealing with all radiators that can be made that comply with
Maxwells laws. As I have said before it is implicite in Maxwells laws
that a efficient radiator can be any size shape or configuration as
long as it complies with Maxwells law.
In my case my small antenna can have any impedance value for
equilibrium and it is quite easy to have a resistive impedance in the
hundreds of ohms as well as minuit impedances. I conform to 50 ohms
purely because of component availability. As another aside my small
antennas
have a much wider bandwidth than any other available! As far as gain
or energy transmitted that all depends on what frequencies get thru
the bandpass filter and in no way directs out of pass energy to be be
redirected to band pass status and augment energy transmitted. Stored
energy has no relationship to Q in my mind since it goes around or
circulates as with a tank circuit energy that lies within the pass
bandof the tank circuit filter.
To summate, my antenna design is considered small yet complies with
Maxwells laws and yet does not have a narrow bandwidth or low
impedance thus Chu's comments cannot be inclusive of all radiators.
Best regards
Art

On Mar 7, 7:29 pm, Art Unwin wrote:

When he brought the question of Q into the picture he made the
statement that small antennas
are usually of a low impedance which is correct empirically with
respect to existing designs but it is not exclusive
when dealing with all radiators that can be made that comply with
Maxwells laws.

I take it your version is gifted and suffers not from a low Q... :/

As I have said before it is implicite in Maxwells laws
that a efficient radiator can be any size shape or configuration as
long as it complies with Maxwells law.

Sure it can. Common knowledge. It's also common knowledge
that the trick with building a small efficient antenna is not really
the size of the radiator itself, it's actually getting power to that
small radiator.


In my case my small antenna can have any impedance value for
equilibrium and it is quite easy to have a resistive impedance in the
hundreds of ohms as well as minuit impedances. I conform to 50 ohms
purely because of component availability. As another aside my small
antennas
have a much wider bandwidth than any other available!

As previously noted, you have reinvented the air cooled dummy
load. Your performance specs sure seem to mimic one anyway.. :/

As far as gain
or energy transmitted that all depends on what frequencies get thru
the bandpass filter and in no way directs out of pass energy to be be
redirected to band pass status and augment energy transmitted. Stored
energy has no relationship to Q in my mind since it goes around or
circulates as with a tank circuit energy that lies within the pass
bandof the tank circuit filter.
To summate, my antenna design is considered small yet complies with
Maxwells laws and yet does not have a narrow bandwidth or low
impedance thus Chu's comments cannot be inclusive of all radiators.
Best regards
Art

As far as the rest, my cat has mittens.. :/
BTW, you need to define "equilibrium".
After several months you still are lagging at this task.
MK

Art Unwin wrote:
On Mar 7, 11:46 am, Jim Lux wrote:

wrote:

I have searched quite a bit for evidence that states that performance
of antennas can be rated by it's size. Formulas do not refere to
radiator size or volume
and aparture is referenced to gain. I understand that sort of thinking
based on Yagi design
but the idea that all small radiators are inefficient is rather
ludicrouse. My work, based on
the sciences of the masters, show that a efficient radiator can be any
size,shape and
configuration as long as it
is in equilibrium . Period
No where can I find reference to "size" in what the masters state
Regards
Art

The work by Chu (Journal of Applied Physics, p1163, v19, Dec 1948) and
subsequently by Harrington (IEEE Trans Ant & Prop, V18#6, Nov 1965,
p896) , Thiele (IEEE Trans on Ant and Prop, v51, #6, June 2003, p1263)
and later others, discusses fundamental limits on performance. Watch
out, though, for the assumptions in the constraints (e.g. whether the
device attached to the feedpoint is reciprocal), and, of course, where
the boundary of the system is.

Watch out also for the definition of "Q", which in this context is the
ratio of stored to disspated/radiated energy, not the ratio of center
frequency/bandwidth.

In short, there is a tradeoff between Q, directivity, and size. And,
because high Q implies high stored energy, for physically realizable
antennas with loss, efficiency is in the mix too.

Googling "chu harrington limit" often turns up useful stuff.


Googled Chu harrington and find that his work is basically empirical
around known arrangements.
When he brought the question of Q into the picture he made the
statement that small antennas
are usually of a low impedance which is correct empirically with
respect to existing designs but it is not exclusive

To summate, my antenna design is considered small yet complies with
Maxwells laws and yet does not have a narrow bandwidth or low
impedance thus Chu's comments cannot be inclusive of all radiators.
Best regards
Art

which is why I mentioned:
"Watch out, though, for the assumptions in the constraints"

However, I believe it is incorrect to characterize his analysis as
empiricism (i.e. getting experimental data and fitting curves). His
analysis (and that of Harrington and Thiele) is entirely theoretical,
and actually doesn't deal with loss in the antenna, per se. Indeed,
Chu's analysis is based on a simple case (a dipole), but that's more
because it's a good first example (and he could use the previous work of
Schelkunoff as a starting point). I believe the analysis is generally
valid, regardless of what the actual antenna is.

On Mar 10, 11:19 am, Jim Lux wrote:
Art Unwin wrote:
On Mar 7, 11:46 am, Jim Lux wrote:

wrote:

I have searched quite a bit for evidence that states that performance
of antennas can be rated by it's size. Formulas do not refere to
radiator size or volume
and aparture is referenced to gain. I understand that sort of thinking
based on Yagi design
but the idea that all small radiators are inefficient is rather
ludicrouse. My work, based on
the sciences of the masters, show that a efficient radiator can be any
size,shape and
configuration as long as it
is in equilibrium . Period
No where can I find reference to "size" in what the masters state
Regards
Art

The work by Chu (Journal of Applied Physics, p1163, v19, Dec 1948) and
subsequently by Harrington (IEEE Trans Ant & Prop, V18#6, Nov 1965,
p896) , Thiele (IEEE Trans on Ant and Prop, v51, #6, June 2003, p1263)
and later others, discusses fundamental limits on performance. Watch
out, though, for the assumptions in the constraints (e.g. whether the
device attached to the feedpoint is reciprocal), and, of course, where
the boundary of the system is.

Watch out also for the definition of "Q", which in this context is the
ratio of stored to disspated/radiated energy, not the ratio of center
frequency/bandwidth.

In short, there is a tradeoff between Q, directivity, and size. And,
because high Q implies high stored energy, for physically realizable
antennas with loss, efficiency is in the mix too.

Googling "chu harrington limit" often turns up useful stuff.

Googled Chu harrington and find that his work is basically empirical
around known arrangements.
When he brought the question of Q into the picture he made the
statement that small antennas
are usually of a low impedance which is correct empirically with
respect to existing designs but it is not exclusive
To summate, my antenna design is considered small yet complies with
Maxwells laws and yet does not have a narrow bandwidth or low
impedance thus Chu's comments cannot be inclusive of all radiators.
Best regards
Art

which is why I mentioned:
"Watch out, though, for the assumptions in the constraints"

However, I believe it is incorrect to characterize his analysis as
empiricism (i.e. getting experimental data and fitting curves). His
analysis (and that of Harrington and Thiele) is entirely theoretical,
and actually doesn't deal with loss in the antenna, per se. Indeed,
Chu's analysis is based on a simple case (a dipole), but that's more
because it's a good first example (and he could use the previous work of
Schelkunoff as a starting point). I believe the analysis is generally
valid, regardless of what the actual antenna is.

You may well be correct. I cannot enter the IEEE papers that you
allude to
to study it furthur. The fact that my impedences are high and the
bandwith is large
is really putting me in a unknown area and I have a lot to learn about
it
Regards
Art

You can pretty much sum up the characteristics of small antennas as:

Small - Broadband - Efficient: Pick any two.

Roy Lewallen, W7EL

On Mar 10, 1:56 pm, Roy Lewallen wrote:
You can pretty much sum up the characteristics of small antennas as:

Small - Broadband - Efficient: Pick any two.

Roy Lewallen, W7EL

Who knows what "efficiency" represents in the electrical world?
It is the word "small" that confuses everybody when the word
should be" fractional wavelength".
Small and large are meaningles in the antenna world.
No I diddn't overlook the sniping.

Art wrote:
"No where can I find reference to "size" in what the masters state"


More diligence!

Terman never failed to have an answer for me. On page 864 of his 1955
0pus he writes:
"The simplest wire radiator or antenna is the elementary doublet shown
in Fig. 23-1a. This consists of a conductor of length small-delta l that
is short compared with the wavelength lambda, and which is assumed to
have such large capacitance areas associated with each end that current
flowing throughout the length of the doublet everywhere has the same
value I. The strength E of the field radiated from such an elementary
antenna in volts per unit length by a current I cos (omega t + 90
degrees) is given by the formula
E = 60 pi/d l/lambda Icos theta cos omega (t-d/c)
Eqn. (23-1)
Here d is the distance from the doublet to a distant receiving point P,
and theta is the direction of P with respect a plane perpendicular to
the axis of the doublet while c is the velocity of light. The strength
of the radiated field is distributed in space in accordance with the
doughnut pattern with a figure-of-eight cross section shown in Fig.
23-1b."

The above is only the beginning of Terman`s chapter on antennas. Fig.
23-2 shows how contributions from multiple doublets in a larger antenna
combine to produce the pattern of the larger antenna. Point to be noted
is that length over lambda is a multiplier in Eqn.(23-1). Obviously size
(length) does make a difference.

Best regards, Richard Harrison, KB5WZI

On Mar 7, 2:08 pm, (Richard Harrison) wrote:
Art wrote:

"No where can I find reference to "size" in what the masters state"

More diligence!

Terman never failed to have an answer for me. On page 864 of his 19550pus he writes:

"The simplest wire radiator or antenna is the elementary doublet shown
in Fig. 23-1a. This consists of a conductor of length small-delta l that
is short compared with the wavelength lambda, and which is assumed to
have such large capacitance areas associated with each end that current
flowing throughout the length of the doublet everywhere has the same
value I. The strength E of the field radiated from such an elementary
antenna in volts per unit length by a current I cos (omega t + 90
degrees) is given by the formula
E = 60 pi/d l/lambda Icos theta cos omega (t-d/c)
Eqn. (23-1)
Here d is the distance from the doublet to a distant receiving point P,
and theta is the direction of P with respect a plane perpendicular to
the axis of the doublet while c is the velocity of light. The strength
of the radiated field is distributed in space in accordance with the
doughnut pattern with a figure-of-eight cross section shown in Fig.
23-1b."

The above is only the beginning of Terman`s chapter on antennas. Fig.
23-2 shows how contributions from multiple doublets in a larger antenna
combine to produce the pattern of the larger antenna. Point to be noted
is that length over lambda is a multiplier in Eqn.(23-1). Obviously size
(length) does make a difference.

Best regards, Richard Harrison, KB5WZI

I disagree. Laws written are all based on the assumption of
equilibrium and that includes
Maxwell's laws. These laws hav e zero refernce to size as such though
many would seek
for the word volume. Pertinent factors are wave length of frequency in
use and root LC.
For equilibrium there is zero reference to size or volume. I ofcourse
fall back to the term equilibrium
which is a basic for Gauss's law of statics to which a variable time
can be added. Thus it can be seen that
a law can be stated that a radiator can be any size, shape or
configuration as long as it is in equilibrium.
The problem here is that amateur radio is wellded to the yagi design
which is not one of equilibrium
and the fact that amateurs and many of the higher educated have pushed
the term of equilibrium
outside the box. This shows up when the uneducated refer to small
antennas as being inefficient
based purely on the connection to a specific design without regard to
whether equilibrium exists
so that all the laws of the masters can be applied. Again, it is
implicite that all laws apply when
there is equilibrium, if there is not then the laws do not apply as
is.
With respect to the term
"length", this is not synonimous to "size" because it has only one
degree of freedom.
There is no reason why a radiator can be rolled up into any shape as
long as the laws of Maxwell
are adhered to and such a sample has been assigned for testing and I
have to be satisfied with the results
as they arrive.I will be soon using one on the radio for QSO's and I
apologise if its use offends anybody
Seems like the group is in quite a tizzy that a person would have a
small radiator that defies
that which has taken them years to memorize. I gave all pertinent
details how to make them
I also gave the mathematics and a sample where established computor
programs confirm the above
and now to upset all again I have given a sample for testing to a
independent reviewer.
There is no need for anybody to worry, Yagi designs still exist for
those who abore change,worry
about transmission line radiation or even radiators melting. When you
all understand the relevence of
equilibrium you can then procede to review the math, until then you
are all in left field.
Best regards
Art
There is nothing in Maxwells laws that prohibit a "wavelength" from
being condensed into the
size of a pinhead or smaller and still be "efficient" with respect to
stated paramitors.