On May 12, 12:42*pm, Jim Lux wrote:
Art Unwin wrote:
On May 11, 4:02 pm, Jim Lux wrote:

Again you preach but obviously you are not qualified to address the
issue.

Opinions on qualification differ.

*AO pro by Beasley consistently produces an array in equilibrium when
the optimizer is used as well as including the presence of particles
dictated by Gauss., The program is of Minninec foundation which
obviously does not require the patch work aproach that NEC has.

Interestingly, MININEC uses the very same method of moments that NEC
does, but, because it's "mini" it has substantial limitations. It was
developed to fit in small microcomputers of the day. *I'd hardly call
NEC "patchwork". The two programs do use different formulations for the
basis function defining the current on the segment.

There are several papers out there that compare the mechanism of MININEC
vs NEC. One might start with the report by Burke and Poggio (for NEC)
and the report by Julian, Logam, and Rockway (which talks about
MININEC). John Rockway published a paper in 1995 describing the history
and differences.
"Advances in MININEC"
John Rockway, James Logan
IEEE Antennas and Propagation Magazine, v37, #4, August 1995, p7-12

I personaly am extremely happy with AO since I am able always to do an
overcheck with respect
the element resonance. I wouldn't be surprised if the next generation
moved away from the present
algerithms and rely purely on number crunching to obtain systems in
equilibrium. I personaly believe
that the programs would be much more accurate if they had a better
understanding of close elements because of proximetry effects. But as
long as the industry strays away from non planar forms we will have to
live with close approximations. Tho using Maxwell to its limits I have
yet to find a way to concentrate radiation for gain as opposed to
efficiency by the introduction of other elements but I enjoy trying
different methods and there is always a new vista that appears with
its use. My next aproach will be a multiplicity of cells or boundaries
dependent on how far my program can spread. One thing I am absolutely
sure now is that particles are the staple of propagation where the
neutrino act as the carrier and can well be the singular particle that
Einstein envisaged based on the Earths two vectors.I was absolutely
over joyed when AO allowed the radiating elements to gyrate towards
zero resistance so that the encapsulating cylinder could be divorced
from element thus removing losses. I see no better proof of my aproach
in making Gaussian static fields dynamic
which clearly exposes the presence of encapsulation that is
substantiated by the math and allows propagation to be viewed as a
point source. Next time one visits the moon they can apply a time
varying current to the space suit to prevent the carrage of particles
to the inside of the ship.
Regards
Art.Unwin

On May 12, 12:10*pm, K1TTT wrote:
On May 11, 8:30*pm, Art Unwin wrote:

When an array is
in equilibrium then Maxwell's equations are exact.

maxwell's equations are ALWAYS exact, it is digital models that are
inexact and have limitations due to the approximations made and the
numeric representations used.

On this I have total agreement. The moment one strays from the concept
of equilibrium is when we expose ourselves to errors.
Regards
Art

On May 10, 7:45*pm, tom wrote:
On 5/10/2010 9:34 PM, Ralph Mowery wrote:





The computer program should know its limits. *Anytine a program allows the
data entered to be too large or small for the calculations, it should be
flagged as being out of range. *Also many computer programs will use
simplified formulars that can mast the true outcome. *Usually it is not very
much, but as all errors start to add up the end results may be way off.

I often enter data that I know will be difficult for programs to use. *If
the program gives an answer then I usually don't use that program expecting
a exect answer.
Back in the Windows 3.1 and 3.11 days the simple calculator would give wrong
answers to simple problems. *I think if you entered 3.11 and subtracted 3.1
from it you got the wrong answer. *That program was not corrected by
Microsoft.

I disagree. *The program cannot "know" its limits if the problem it's
modeling is complex enough. *So the user must understand the program and
especially the math related to what the program is modeling.

Blaming the program for giving you the "wrong" answer is like blaming
the tires for hitting the guard rail because you exceeded their limits.
* Those limits are not the same under varying conditions and must be
filtered by experience and understanding.

tom
K0TAR

I've found it in my best interest to check the consistency of results
in various ways, whenever I can. Often there's more than one way to
think about a problem, and if the answers I get differ, I want to know
why. Until I can resolve the differences, I distrust both (or all...)
answers. I also like to have an idea about the tolerance on the
answers, and many programs (and formulas you use to calculate answers
for yourself) don't give much of a clue about the tolerance. Some are
"exact," and some should be considered only approximations, but often
they don't bother to tell you which. One example is formulas for
calculating the impedance of TEM transmission lines; it's common to
see, for air-dielectric two-wire line, Z0=276*log10(2D/d), but this is
an approximation whose error becomes significant as d approaches D.
Even the better formula, Z0=120invcosh(D/d), is not exact: the 120
isn't exactly correct, there's no consideration of finite conductor
resistance (and resulting skin depth), and there's no consideration of
the atmospheric pressure and relative humidity...

I mostly agree with Tom: don't expect the program, or formula, to
know how you are going to misapply it. Try to be aware of what the
answers you get imply. Learn the limits of your tools (programs;
formulas), and apply them wisely so they will serve you well.

Do I get stung by my own foolishness in not paying proper attention to
things like this? You bet I do! Just last night, I entered a coil
into the Hamwaves inductance calculator and it was happy to give me an
answer. The coil? Ten turns of 1mm wire in a coil 10mm diameter and
10mm long... Duh, that's a 1mm winding pitch and the turns will short
together. I didn't think to check that at first. The calculator
complains and won't give you an answer if the pitch is less than the
wire diameter, but not if it's just equal. Considering the same very
useful inductance calculator, I've learned to ignore the answer for
the effective shunt stray capacitance: it in general doesn't come
close to matching the value calculated from the self-resonance and the
inductance. To see what I mean, try entering D=10mm, N=10, len.=20mm,
d=1mm, and check what C(L,p) is reported. Now try changing D in 1mm
increments up and down. OK, so I don't trust the reported C(L,p)
value, but because I've checked several cases of all the other
reported values against measurements of actual coils and against one
or two other programs I use, I've learned to trust those other
reported values, within some tolerance (that's a lot looser than the
reported precision in the calculator!). -- I don't mean to pick on
that inductance calculator, just to use it to illustrate what applies
to pretty much all calculation programs and formulas.

Cheers,
Tom

On May 12, 12:58*pm, K7ITM wrote:
....
To see what I mean, try entering D=10mm, N=10, len.=20mm,
d=1mm, and check what C(L,p) is reported. *Now try changing D in 1mm
increments up and down. *OK, so I don't trust the reported C(L,p)
value, ...

OK, it also helps to RTFM. The text down below the inductance
calculator explains about this some. Also, I should have said that
you need to set the "design frequency" to something low (e.g. 10MHz)
to see the effect. However, the text suggests that C(L,p) value would
be larger than expected...and I've also seen it for some coils to be
considerably smaller. So I end up, then, not finding the lumped model
including C(L,p) being very useful for the things I do, where I want a
model that gives me _decent_ agreement over a broader frequency range,
rather than perhaps more exact agreement over a very limited frequency
range (as happens when the reported value of C(L,p) gets very large;
try "design frequency" = 1MHz for that coil).

Cheers,
Tom

On May 12, 3:16*pm, K7ITM wrote:
On May 12, 12:58*pm, K7ITM wrote:
...

To see what I mean, try entering D=10mm, N=10, len.=20mm,
d=1mm, and check what C(L,p) is reported. *Now try changing D in 1mm
increments up and down. *OK, so I don't trust the reported C(L,p)
value, ...

OK, it also helps to RTFM. *The text down below the inductance
calculator explains about this some. *Also, I should have said that
you need to set the "design frequency" to something low (e.g. 10MHz)
to see the effect. *However, the text suggests that C(L,p) value would
be larger than expected...and I've also seen it for some coils to be
considerably smaller. *So I end up, then, not finding the lumped model
including C(L,p) being very useful for the things I do, where I want a
model that gives me _decent_ agreement over a broader frequency range,
rather than perhaps more exact agreement over a very limited frequency
range (as happens when the reported value of C(L,p) gets very large;
try "design frequency" = 1MHz for that coil).

Cheers,
Tom

Remember, I have always specified that one does not go beyond the
units supplied by Maxwell, Maxwell did not use lumped loads. It is
stipulated
that equilibrium is paramount as soon as you see the "=" sign. Thus I
can say I am persueing exactnes or accuracy and not fudging.It was
when Maxwell followed the edict of the "equal" sign that he was forced
to add the particle elevation vector by the addition of displacement
current even tho
he could not describe the addition. To him it was a mathematical
equation and nothing else and without explanation of the process.
Art

On May 12, 3:29*pm, Art Unwin wrote:
On May 12, 12:10*pm, K1TTT wrote:

On May 11, 8:30*pm, Art Unwin wrote:

When an array is
in equilibrium then Maxwell's equations are exact.

maxwell's equations are ALWAYS exact, it is digital models that are
inexact and have limitations due to the approximations made and the
numeric representations used.

On this I have total agreement. The moment one strays from the concept of equilibrium is when we expose ourselves to errors.
Regards
Art

ok, so you DO agree that maxwell's equations that make no mention of
particles like neutrinos, gravity, coriolis forces, or levitation ARE
correct! And therefor you must agree that the representation of
gauss's law encapsulated in maxwell's equations, WITHOUT an explicit t
in it must be correct! You must also be admitting that your
optimization experiments are full of errors. wow, now its time to go
and rejoice, art has finally come around to the real world!

On May 12, 3:16*pm, K7ITM wrote:
On May 12, 12:58*pm, K7ITM wrote:
...

To see what I mean, try entering D=10mm, N=10, len.=20mm,
d=1mm, and check what C(L,p) is reported. *Now try changing D in 1mm
increments up and down. *OK, so I don't trust the reported C(L,p)
value, ...

OK, it also helps to RTFM. *The text down below the inductance
calculator explains about this some. *Also, I should have said that
you need to set the "design frequency" to something low (e.g. 10MHz)
to see the effect. *However, the text suggests that C(L,p) value would
be larger than expected...and I've also seen it for some coils to be
considerably smaller. *So I end up, then, not finding the lumped model
including C(L,p) being very useful for the things I do, where I want a
model that gives me _decent_ agreement over a broader frequency range,
rather than perhaps more exact agreement over a very limited frequency
range (as happens when the reported value of C(L,p) gets very large;
try "design frequency" = 1MHz for that coil).

Cheers,
Tom

Again I state. If you are using Maxwell equations you cannot stray
from the units supplied.Hams do not follow the rules with respect
to antennas so approximations are literally garranteed.
Using Maxwells equations alone you have the presence of point
radiation. With a single point radiation the rules of physics state
that radiation limits is in the form of a sphere. If one states you
cannot have a sphere of radiation they are breaking all the laws of
physics and I certainly had no part in the making of the rules.
Regards
Art

On May 12, 4:49*pm, Art Unwin wrote:
On May 12, 3:16*pm, K7ITM wrote:





On May 12, 12:58*pm, K7ITM wrote:
...

To see what I mean, try entering D=10mm, N=10, len.=20mm,
d=1mm, and check what C(L,p) is reported. *Now try changing D in 1mm
increments up and down. *OK, so I don't trust the reported C(L,p)
value, ...

OK, it also helps to RTFM. *The text down below the inductance
calculator explains about this some. *Also, I should have said that
you need to set the "design frequency" to something low (e.g. 10MHz)
to see the effect. *However, the text suggests that C(L,p) value would
be larger than expected...and I've also seen it for some coils to be
considerably smaller. *So I end up, then, not finding the lumped model
including C(L,p) being very useful for the things I do, where I want a
model that gives me _decent_ agreement over a broader frequency range,
rather than perhaps more exact agreement over a very limited frequency
range (as happens when the reported value of C(L,p) gets very large;
try "design frequency" = 1MHz for that coil).

Cheers,
Tom

Again I state. *If you are using Maxwell *equations you cannot stray
from the units supplied.Hams do not follow the rules with respect
to antennas so approximations are literally garranteed.
Using Maxwells equations alone you have the presence of point
radiation. With a single point radiation the rules of physics state
that radiation limits is in the form of a sphere. If one states you
cannot have a sphere of radiation they are breaking all the laws of
physics and I certainly had no part in the making of the rules.
Regards
Art- Hide quoted text -

- Show quoted text -

you can have a spherically symetric static electric field as is easily
shown by gauss's law. but in order to have 'radiation' (implying em
wave propagating through space) you must have movement of some kind,
that immediately removes the spherical symetry by creating an axis
defined by the direction of movement. this is why even the
theoretical infinitesimal dipole still produces a doughnut shaped
field in free space.

On May 12, 3:49*pm, Art Unwin wrote:


Again I state. *If you are using Maxwell *equations you cannot stray
from the units supplied.Hams do not follow the rules with respect
to antennas so approximations are literally garranteed.

Maybe this is good.. I have noticed my antennas tend to actually
work as radiators of RF, where as most of yours seem to prefer
to turn it to heat. :/ I think Maxwell must be taking you for a big
ride. I bet he's up there is the land of the big RF just laughing his
head off at all this silly jibber jabber you keep blaming him for.

Using Maxwells equations alone you have the presence of point
radiation. With a single point radiation the rules of physics state
that radiation limits is in the form of a sphere. If one states you
cannot have a sphere of radiation they are breaking all the laws of
physics and I certainly had no part in the making of the rules.
Regards
Art

How many cases of a single point of radiation have you seen
in the real world, using real world antennas? This is not a trick
question.

On May 11, 9:23*pm, tom wrote:
I don't know what the problem is, Cecil, it looks perfectly normal to
me.

Yep, one of its claims to fame is that it passes all the geometry and
segmentation checks that EZNEC runs. However, it does violate the
"spacing of elements" admonition in the manual.
--
73, Cecil, w5dxp.com