On Mar 23, 1:50*pm, "Joel Koltner"
wrote:
Hi Tim,

"TimShoppa" wrote in message

...
On Mar 22, 9:24 pm, "Joel Koltner"
wrote:

I think his method, especially for physically compact antennas and
feed systems which tend to have very low radiation resistance at HF
frequencies, is a great check on theoretical calculations. There has
to be a meeting point between mathematical models/NEC and reality and
he is working at one such point.

Agreed -- the controversy comes into play in that he ends up computing
electrically-small loop antennas as being upwards of 70-90% efficient, when
everyone "knows" that such antennas are typically 10% efficient. *He even
goes after Chu/Wheeler/McLean/etc. in suggesting that the fundamental limits
for the Q of an ESA are orders of magnitude off (slide 47), and that's pretty
sacrosanct terriority (see, e.g.,www.slyusar.kiev.ua/Slyusar_077.pdf*-- even
the Ruskies buy into the traditional results :-) ).

Hence, while I don't really have the background to know precisely how much of
what Underhill promotes is true or not, it's definitely intriguing to me, and
I'm looking around for various rebuttals by those more skilled in the art than
I am.

One link I found:http://qcwa70.org/truth%20and%20untruth.pdf(but this was
written before the PowerPoint presentation I originally linked to).

I'm pretty sure that it is not so easy to just measure power in, heat
lost, and assume that everything else is being usefully radiated.

I think that after you've modeled and then built an antenna, that heat
loss and temperature measurements are valuable to determine if the
assumptions you put into the NEC model regarding loss etc. are correct
or not, and where you need to improve your model, especially of
materials like dielectrics.

Even the heat loss measurements require some fairly heavy modeling
just to convert the IR camera images to actual watts per square cm.
Think it's purely radiative? Sometimes yeah, but make the wrong
assumption when really it's convective and you can be off by a factor
of ten to thirty.

Tim.

On Mar 23, 9:35*pm, Tim Shoppa wrote:
On Mar 23, 1:50*pm, "Joel Koltner"
wrote:



Hi Tim,

"TimShoppa" wrote in message

...
On Mar 22, 9:24 pm, "Joel Koltner"
wrote:

I think his method, especially for physically compact antennas and
feed systems which tend to have very low radiation resistance at HF
frequencies, is a great check on theoretical calculations. There has
to be a meeting point between mathematical models/NEC and reality and
he is working at one such point.

Agreed -- the controversy comes into play in that he ends up computing
electrically-small loop antennas as being upwards of 70-90% efficient, when
everyone "knows" that such antennas are typically 10% efficient. *He even
goes after Chu/Wheeler/McLean/etc. in suggesting that the fundamental limits
for the Q of an ESA are orders of magnitude off (slide 47), and that's pretty
sacrosanct terriority (see, e.g.,www.slyusar.kiev.ua/Slyusar_077.pdf*-- even
the Ruskies buy into the traditional results :-) ).

Hence, while I don't really have the background to know precisely how much of
what Underhill promotes is true or not, it's definitely intriguing to me, and
I'm looking around for various rebuttals by those more skilled in the art than
I am.

One link I found:http://qcwa70.org/truth%20and%20untruth.pdf(butthis was
written before the PowerPoint presentation I originally linked to).

I'm pretty sure that it is not so easy to just measure power in, heat
lost, and assume that everything else is being usefully radiated.

I think that after you've modeled and then built an antenna, that heat
loss and temperature measurements are valuable to determine if the
assumptions you put into the NEC model regarding loss etc. are correct
or not, and where you need to improve your model, especially of
materials like dielectrics.

Even the heat loss measurements require some fairly heavy modeling
just to convert the IR camera images to actual watts per square cm.
Think it's purely radiative? Sometimes yeah, but make the wrong
assumption when really it's convective and you can be off by a factor
of ten to thirty.

Tim.

But Tim Maxwells equations are accepted every where and appear to be
valid.
Because of this antenna computer programs are based on these
equations.
Thus when a optimiser is added the program can change the input to one
that satisfies
Maxwells equations. Assuming programers did a good job in focusing on
the Maxwell equations then we are provided with an array that meets
Maxwells equations.
What more can we possibly need other than a program that accounts for
all forces involved for the generation of ALL radiation available for
communication use that can be propagated
If we have a distrust in the programers or in Maxwells laws then one
should ditch the arrays
supplied by an optimiser and find what some refer to as a "new
technology." Until one comes along we first have to delegitemise
Maxwell and we have been unable to do that!
Maxwells equations can be justified via all known laws in physics
including making static laws dynamic. and adhering to the absolute
requirement of equilibrium with respect to physics laws. The main
problem we have is misinterpretations we add by using lumped loads etc
which Maxwell never included same. This also is the case with the yagi
where
Maxwell never supplied anything with respect to planar or even a
stipulation that elements must be straight, parallel, resonant,
etc ,only EQUILIBRIUM. where all data can be placed on one side of an
equal sign and where on the other side MUST equal zero..
So we dance with the one that 'brung' us
Regards
Art

On Mar 24, 3:32*am, Art Unwin wrote:
On Mar 23, 9:35*pm, Tim Shoppa wrote:



On Mar 23, 1:50*pm, "Joel Koltner"
wrote:

Hi Tim,

"TimShoppa" wrote in message

....
On Mar 22, 9:24 pm, "Joel Koltner"
wrote:

I think his method, especially for physically compact antennas and
feed systems which tend to have very low radiation resistance at HF
frequencies, is a great check on theoretical calculations. There has
to be a meeting point between mathematical models/NEC and reality and
he is working at one such point.

Agreed -- the controversy comes into play in that he ends up computing
electrically-small loop antennas as being upwards of 70-90% efficient, when
everyone "knows" that such antennas are typically 10% efficient. *He even
goes after Chu/Wheeler/McLean/etc. in suggesting that the fundamental limits
for the Q of an ESA are orders of magnitude off (slide 47), and that's pretty
sacrosanct terriority (see, e.g.,www.slyusar.kiev.ua/Slyusar_077.pdf*-- even
the Ruskies buy into the traditional results :-) ).

Hence, while I don't really have the background to know precisely how much of
what Underhill promotes is true or not, it's definitely intriguing to me, and
I'm looking around for various rebuttals by those more skilled in the art than
I am.

One link I found:http://qcwa70.org/truth%20and%20untruth.pdf(butthiswas
written before the PowerPoint presentation I originally linked to).

I'm pretty sure that it is not so easy to just measure power in, heat
lost, and assume that everything else is being usefully radiated.

I think that after you've modeled and then built an antenna, that heat
loss and temperature measurements are valuable to determine if the
assumptions you put into the NEC model regarding loss etc. are correct
or not, and where you need to improve your model, especially of
materials like dielectrics.

Even the heat loss measurements require some fairly heavy modeling
just to convert the IR camera images to actual watts per square cm.
Think it's purely radiative? Sometimes yeah, but make the wrong
assumption when really it's convective and you can be off by a factor
of ten to thirty.

Tim.

But Tim Maxwells equations are accepted every where and appear to be
valid.
Because of this antenna computer programs are based on these
equations.
Thus when a optimiser is added the program can change the input to one
that satisfies
Maxwells equations. Assuming programers did a good job in focusing on
the Maxwell equations then we are provided with an array that meets
Maxwells equations.
What more can we possibly need other than a program that accounts for
all forces involved for the generation of ALL radiation available for
communication use that can be propagated
If we have a distrust in the programers or in Maxwells laws then one
should ditch the arrays
supplied by an optimiser and find what some refer to as a "new
technology." Until one comes along we first have to delegitemise
Maxwell and we have been unable to do that!

up to here this is the most lucid thing i think i have seen art
write... and then he starts going down hill.


Maxwells equations can be justified via all known laws in physics
including making static laws dynamic. and adhering to the absolute
requirement of equilibrium *with respect to physics laws. The main
problem we have is misinterpretations we add by using lumped loads etc
which Maxwell never included same. This also is the case with the yagi
where
Maxwell never supplied anything with respect to planar or even a
stipulation that elements must be straight, parallel, resonant,
etc ,only EQUILIBRIUM. where all data can be placed on one side of an
equal sign and where on the other side MUST equal zero..
So we dance with the one that 'brung' us
Regards
Art

the planar designs are a _result_ of maxwell's equations plus some
basic mechanical engineering considerations. coupling between
parallel wires or tubes is predictable and easily controlled by
adjusting length and spacing, all in accordance with maxwell's
equations, to make a family of easily designed and constructed
antennas. are they the ultimate, no, i quoted you a book probably a
couple years ago where an optimizer was used and came up with planar
elements that were more like a wavelength long but shaped like a cross
section of a bowl. a 3d optimizer can do other things, but then you
loose some of the important characteristics of the Yagi-Uda arrays,
like the control of polarization and ease of construction. and yes,
you can use maxwell's equations to model lumped elements, you just
have to model them on the appropriate scale with a program that
handles very small segments.

On Mar 23, 12:13*pm, Tim Shoppa wrote:
On Mar 22, 9:24*pm, "Joel Koltner"
wrote:

I know that many people think G3LHZ is a little bit off his rocker, but out of
curiosity... what he suggests on slide 15 hehttp://frrl.files.wordpress.com/2009...ts-of-small-an...
- is that a valid approach to measuring antenna efficiency? -- Use a thermal
camera to note how much an antenna heats up with a given input power, find out
how much DC power it required to heat it to the same temperature (the
antenna's loss), and -- poof! -- antenna efficiency = (input power-loss)/input
power?

What are the significant loss mechanisms that he's not accounting for? *(He
claims his matching network isn't getting at all hot.)

With some feedlines and frequencies, feedline radiation can become an
issue. For example, using 4" ladder line at UHF.

I think his method, especially for physically compact antennas and
feed systems which tend to have very low radiation resistance at HF
frequencies, is a great check on theoretical calculations. There has
to be a meeting point between mathematical models/NEC and reality and
he is working at one such point. There are of course other points too
(e.g. near field and far field measurements).

Tim.

I can't see how the external fields come into it! That would
automatically be within the two vectors that supply acceleration, this
would be measure by the skin depth created by the displacement
current. The accelleration of charge is a constant dependent on the
conductor used. Where the particle goes when acceleration stops i.e.
after leaving the boundary is of no consequence.This would be seen in
the oscillation losses of the radiator
in the same way as with a pendulum

On Mar 23, 1:56*pm, Art Unwin wrote:
On Mar 23, 12:13*pm, Tim Shoppa wrote:



On Mar 22, 9:24*pm, "Joel Koltner"
wrote:

I know that many people think G3LHZ is a little bit off his rocker, but out of
curiosity... what he suggests on slide 15 hehttp://frrl.files.wordpress.com/2009...ts-of-small-an...
- is that a valid approach to measuring antenna efficiency? -- Use a thermal
camera to note how much an antenna heats up with a given input power, find out
how much DC power it required to heat it to the same temperature (the
antenna's loss), and -- poof! -- antenna efficiency = (input power-loss)/input
power?

What are the significant loss mechanisms that he's not accounting for? *(He
claims his matching network isn't getting at all hot.)

With some feedlines and frequencies, feedline radiation can become an
issue. For example, using 4" ladder line at UHF.

I think his method, especially for physically compact antennas and
feed systems which tend to have very low radiation resistance at HF
frequencies, is a great check on theoretical calculations. There has
to be a meeting point between mathematical models/NEC and reality and
he is working at one such point. There are of course other points too
(e.g. near field and far field measurements).

Tim.

I can't see how the external fields come into it! * That would
automatically be within the two vectors that supply acceleration, this
would be measure by the skin depth created by the displacement
current. The accelleration of charge is a constant dependent on the
conductor used. Where the particle goes when acceleration stops i.e.
after leaving the boundary is of no consequence.This would be seen in
the oscillation losses of the radiator
in the same way as with a pendulum

If you dont understand external fields then you dont understand
Maxwell's equations at all. Maxwell is all about fields. This pretty
much means you havent had a clue about anything you have ever said
about antennas.

Jimmie

On Mar 23, 1:10*pm, JIMMIE wrote:
On Mar 23, 1:56*pm, Art Unwin wrote:



On Mar 23, 12:13*pm, Tim Shoppa wrote:

On Mar 22, 9:24*pm, "Joel Koltner"
wrote:

I know that many people think G3LHZ is a little bit off his rocker, but out of
curiosity... what he suggests on slide 15 hehttp://frrl.files.wordpress.com/2009...ts-of-small-an...
- is that a valid approach to measuring antenna efficiency? -- Use a thermal
camera to note how much an antenna heats up with a given input power, find out
how much DC power it required to heat it to the same temperature (the
antenna's loss), and -- poof! -- antenna efficiency = (input power-loss)/input
power?

What are the significant loss mechanisms that he's not accounting for? *(He
claims his matching network isn't getting at all hot.)

With some feedlines and frequencies, feedline radiation can become an
issue. For example, using 4" ladder line at UHF.

I think his method, especially for physically compact antennas and
feed systems which tend to have very low radiation resistance at HF
frequencies, is a great check on theoretical calculations. There has
to be a meeting point between mathematical models/NEC and reality and
he is working at one such point. There are of course other points too
(e.g. near field and far field measurements).

Tim.

I can't see how the external fields come into it! * That would
automatically be within the two vectors that supply acceleration, this
would be measure by the skin depth created by the displacement
current. The accelleration of charge is a constant dependent on the
conductor used. Where the particle goes when acceleration stops i.e.
after leaving the boundary is of no consequence.This would be seen in
the oscillation losses of the radiator
in the same way as with a pendulum

If you dont understand external fields then you dont understand
Maxwell's equations at all. Maxwell is all about fields. This pretty
much means you havent had a clue about anything you have ever said
about antennas.

Jimmie

Jimmy
I am referring to the boundary laws which is energy in versus energy
out.
Maxwells laws finish with the completion of acceleration of charge.
The boundary laws are covered by this action and reaction per Newton.
The particle that is accellerated is the smallest known with respect
to mass and we know that it is accellerated to the speed of light
which is known for any particular medium.
Thus knowing the energy supplied we must equate it to the ejection
vector applied to the particles and the reaction force applied to the
radiating member.
NEC computer programs do just this and for such equations produce
arrays where each
element is resonant and tipped to oppose the two vectors of gravity
and the rotation of the Earth by supplying the array only where it is
in a state of equilibrium and all elements are resonant as a result of
the initial two vectors. The NEC computer programs do just this when
applying Newton's laws which are not mismanaged to reflect planar
forms.
Again I state that Newtons equations account for all vectors involved
in radiation and does not in any way reflect the fields that are
generated beyond acceleration and how the particles are dispersed
beyond this point. This way it represents all types of radiation that
the radiator is capable of and likewise makes it sensitive to all that
is thrown at the receiving end ie H,V, cw, ccw signals e.t.c. and all
the rest that is thrown at it which it converts to a useable current
signal for the radio.Now if you are still in a state of flux as to the
use of equilibrium in all the laws of the Universe then you are still
spitting into the wind.
Art Unwin KB9MZ....xg

On 3/23/2010 1:44 PM, Art Unwin wrote:
On Mar 23, 1:10 pm, wrote:
On Mar 23, 1:56 pm, Art wrote:



On Mar 23, 12:13 pm, Tim wrote:

On Mar 22, 9:24 pm, "Joel
wrote:

I know that many people think G3LHZ is a little bit off his rocker, but out of
curiosity... what he suggests on slide 15 hehttp://frrl.files.wordpress.com/2009...ts-of-small-an...
- is that a valid approach to measuring antenna efficiency? -- Use a thermal
camera to note how much an antenna heats up with a given input power, find out
how much DC power it required to heat it to the same temperature (the
antenna's loss), and -- poof! -- antenna efficiency = (input power-loss)/input
power?

What are the significant loss mechanisms that he's not accounting for? (He
claims his matching network isn't getting at all hot.)

With some feedlines and frequencies, feedline radiation can become an
issue. For example, using 4" ladder line at UHF.

I think his method, especially for physically compact antennas and
feed systems which tend to have very low radiation resistance at HF
frequencies, is a great check on theoretical calculations. There has
to be a meeting point between mathematical models/NEC and reality and
he is working at one such point. There are of course other points too
(e.g. near field and far field measurements).

Tim.

I can't see how the external fields come into it! That would
automatically be within the two vectors that supply acceleration, this
would be measure by the skin depth created by the displacement
current. The accelleration of charge is a constant dependent on the
conductor used. Where the particle goes when acceleration stops i.e.
after leaving the boundary is of no consequence.This would be seen in
the oscillation losses of the radiator
in the same way as with a pendulum

If you dont understand external fields then you dont understand
Maxwell's equations at all. Maxwell is all about fields. This pretty
much means you havent had a clue about anything you have ever said
about antennas.

Jimmie

Jimmy
I am referring to the boundary laws which is energy in versus energy
out.
Maxwells laws finish with the completion of acceleration of charge.

Hmmmmmm.

I thought that you claimed Maxwell is STATIC.

How can anything static accelerate something?

Sorry, I should have spelled it "accellerated", which is probably
another new thing you have made up. So if that's what's going on here,
I apollojive.

tom
K0TAR

The boundary laws are covered by this action and reaction per Newton.
The particle that is accellerated is the smallest known with respect
to mass and we know that it is accellerated to the speed of light
which is known for any particular medium.
snip nonsense
/snip nonsense
Art Unwin KB9MZ....xg

On Mon, 22 Mar 2010 18:24:06 -0700, "Joel Koltner"
wrote:

What are the significant loss mechanisms that he's not accounting for? (He
claims his matching network isn't getting at all hot.)

Hi Joel,

Your source is thrashing against a number of conventions that he has
disproved by relying on Schopenhauer - what a wheeze! This is the
same argument that "revolutionary" thinkers appeal to forgetting that
their theories can be dismissed by the same mechanism.

Let's examine this heuristically (irony there). Two observations
provided by your source raise the temperature of
1. a can by 100 deg C with 100W;
2. a tube by 100 deg C with 150W.
Heat is always concerned with mass and surface area, and heat transfer
is expressed in Watts per square Meter. Temperature rise is expressed
in joules for specific heat capacity and mass.

The two examples provided by the source differ by -50/+100% in heat
transfer. How does this impact the development of a "new theory?"
Let's revisit the two examples normalized to transfer:
1. the can exhibits 127W/m²
2. the tube exhibits 57.7W/m²
Such discrepancies are meaningless? I assume so, because the source
doesn't respond to answering them.

There is, of course, a very simple explanation that heuristics reveals
in specific heat capacity (a term completely absent from the
discussion of heat in a radiator).

Let's consider the nearly 1m loop with a heating wire inside -
curiously unspecified for such a "scientific" and unbiased report. It
is, in fact, an 18ga wire of 80% nickel and 20% chromium (yes
nichrome) which by the current supplied heats up to 550 deg. C. These
details must be immaterial to the original source that ignores them.

Could one imagine a heater wire at 550deg. C heating the outer tube by
100 deg C only? Well, let's consider that light bulb in the can that
exhibits double the heat transfer. It's filament is running at
somewhere between 2200 and 3000 deg C for the same temperature rise.
Nature must have some curious law of heat plateau in this "new
theory."

If we were to rely on heat reportings alone to carry the logic, then
this vast wobbly range of -50/+100% reported values is not very
compelling. Intuition is often appealed to in these pages (some call
it heuristics); and it would seem that the heated wire, with 150W and
supporting 550 deg C would eventually melt the antenna components.
Where else is the heat at that temperature going? It is entirely
contained by the copper tube. Yet our source does not reveal this -
and ironically points out that would be the fate if RF could raise
temperatures.

However, temperature is NOT power. How much power would it take to
raise that specific 83 cm diameter looped 10 mm copper tube 100 deg C?
The answer is 2.16 W-Hours. The 550 deg C hot wire is
running at 150 W continuous and only pumping
up the temperature a paltry 100 deg C.
That is pretty pathetic.

The answer is ALSO 7800 W-Seconds.
Clearly 150W for several seconds wouldn't
make a noticeable heat boost.
That is pretty pathetic too.

Obviously heat rise is a product of time (the term "rise" demands
this) and yet throughout this source's "scientific" and unbiased
report time measurement for these heat readings are wholly absent. How
many in this forum recognize the duty cycle of a typical QSO in this?
How many antenna failures follow from heat, how many QSOs still suffer
from poor efficiency?

For those who care, the formula is simple:
Q = m · C · (Tf - Ti)
where
Q is joules
m is mass in grams
Tf is final temperature (K or C)
Ti is initial temperature (K or C)
C is specific heat capacity in
J/(K · g)
or
J/(C · g)
and for copper is 0.39

For comparison, water's specific heat capacity is 4.18, more than ten
times higher and thus more power is required to raise water that same
100 deg. and this is why water is used in radiators. Mineral oil runs
about half that (and folks struggle to obtain transformer oil for
their dummy loads when water is superior).

An aluminum tube at 0.90 is thus going to run cooler than copper when
we put a heater wire inside (for the same, unstated, time interval).

Given the inordinate number of facts missing, undisclosed time
intervals, no discussion of heat capacity (in a heat report) and the
obvious cynicism cloaked in "heuristics, science, and unbias" -
further reading on other topics has every chance of being equally
blighted.

To put icing on the cake, I am astonished that the original source can
only eke out low 90s percent efficiency in the 20M band! To employ
the original source's arguments: Put 450W to that sucker and tell us
where the 20 to 30W were lost. As it takes only 2W-Hr to raise that
antenna 100 deg C, that air cooled dummy load must be boiling rain and
burning fog.

--- and then again, maybe I did the math wrong.....

73's
Richard Clark, KB7QHC

On the surface, the method seems reasonable. However, remember that heat
(which is energy) is removed by three mechanisms: conduction,
convection, and radiation. And the temperature rise depends on the rate
heat is lost through these three. The effectiveness of each mechanism
will be different for each part of the antenna structure. So to
realistically judge the temperature rise due to RF compared to DC, the
two have to be distributing heat to the same parts of the antenna in the
same amounts. This isn't a trivial task, and no care was taken to do so.

An additional problem with the method is that no attempt was apparently
made to actually measure the amount of RF power being applied to the
antenna. So knowing the amount of power required for equal heating would
be insufficient for determining efficiency even if it could be
accurately measured.

That the method fails is demonstrated by the results. The author
concludes that the sample antennas have much higher efficiency than
known and proven physical laws predict and countless measurements have
confirmed. He's proposed "correcting" NEC, which applies known and
proven physical laws, to agree with his "heuristic" measurements based
on poor methodology and no direct measurement of efficiency such as
field strength. This is a common theme of junk science, and firmly
identifies this work as being in that category. A search for flaws in
his measurement methods is much more likely to be fruitful than
searching for fundamental flaws in NEC and current physical laws.

But I'm sure that some of the same folks who swallow homeopathic
remedies and arrange their lives around astrological predictions will
replace their 160 meter towers with tiny wire loops. P.T. Barnum's
famous observation is still true.

Roy Lewallen, W7EL

Thanks Roy, your observations and Richard's detailed discussion are just what
I was looking for.

I hope you sell a bunch of copies of EZNEC at Dayton this year!

---Joel