On May 10, 12:35*pm, Art Unwin wrote:
I just completed a experiment with my antenna optimizer program where
I had a dipole in free space and where I increased the diameter until
it was close to.003 ohms resistive
What this means is the current flow is right at the surface where
there is no skin depth
penetration involved and thus close to zero material resistance. This
means that the total resistance is the radiation resistance of the
surface encapsulating particles. The radiation was 35 db in a shape
close to that of a sphere. (when the resistance of the aluminum dipole
went to zero the radiation went to a perfect sphere) Efficiency was
stated at 100% efficient pointing to 100% accountability for all
forces involved and where losses were at a minimum.
Regards
Art

Where is Lurch when I need him.... Grrrrrrrrrrrrrrrr...
Once again , delusions of grandeur induced by misuse of antenna
modeling programs. :/

On 5/10/2010 3:12 PM, wrote:
On May 10, 12:35 pm, Art wrote:
I just completed a experiment with my antenna optimizer program where
I had a dipole in free space and where I increased the diameter until
it was close to.003 ohms resistive
What this means is the current flow is right at the surface where
there is no skin depth
penetration involved and thus close to zero material resistance. This
means that the total resistance is the radiation resistance of the
surface encapsulating particles. The radiation was 35 db in a shape
close to that of a sphere. (when the resistance of the aluminum dipole
went to zero the radiation went to a perfect sphere) Efficiency was
stated at 100% efficient pointing to 100% accountability for all
forces involved and where losses were at a minimum.
Regards
Art

Where is Lurch when I need him.... Grrrrrrrrrrrrrrrr...
Once again , delusions of grandeur induced by misuse of antenna
modeling programs. :/

As Clint said in the wonderful old movie, "A man's gotta know his
limits". For antenna modelers it should read, "A man's gotta know the
program's limits".

Of course, Art thinks things have changed and the computer modelers have
a better grasp upon reality than the ones even he calls "the masters".
He is an example of the blind man leading himself.

tom
K0TAR

"tom" wrote in message
t...
On 5/10/2010 3:12 PM, wrote:
As Clint said in the wonderful old movie, "A man's gotta know his limits".
For antenna modelers it should read, "A man's gotta know the program's
limits".

Of course, Art thinks things have changed and the computer modelers have a
better grasp upon reality than the ones even he calls "the masters". He is
an example of the blind man leading himself.

tom
K0TAR

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.

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

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, 3:16*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 5/12/2010 3:16 PM, K7ITM wrote:
On May 12, 12:58 pm, 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



You are amusing in an engineer unix geek kind of way. Just the kind of
thing that annoyed my ex.

tom
K0TAR

On May 10, 9:34*pm, "Ralph Mowery" wrote:
"tom" wrote in message

t...

On 5/10/2010 3:12 PM, wrote:
As Clint said in the wonderful old movie, "A man's gotta know his limits".
For antenna modelers it should read, "A man's gotta know the program's
limits".

Of course, Art thinks things have changed and the computer modelers have a
better grasp upon reality than the ones even he calls "the masters". He is
an example of the blind man leading himself.

tom
K0TAR

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.

Ralph, the computer program I use is AO pro which is equipt with an
optimiser and based on Maxwells equation. It is required to provide
arrays where the whole is in equilibrium as is its parts where all
forces are taken into account according to boundary rules.
It is quite easy to confirm if the results are in equilibrium.There
are many programs that arer similar
only they will not crunch the numbers as an optimiser will but instead
calculate only from your input but without alteration. These also are
based on Maxwells equations. However hams are bound to Yagi style
antenna designs which are planar and not in equilibrium. This style of
program is modified to encompass its primary use. There are also
programs that are specifically designed for planar arrangement only
per the Yagi and are not based solely on Maxwell equations that demand
equilibrium.
To apply any of these programs is ok for a dipole in free space say
for 14 Mhz and should give the same results. Same goes if one changes
the diameter as will the radiation pattern provided. So in this
particular
situation it matters not what program one uses the results will be the
same. To conform with Maxwells equation equilibrium is demanded ie all
vectors add up to zero.Since it is based on boundary rules one can
make a static field dynamic which thus includes particles where the
result is applicable to Maxwells equations. Thus we have an conductive
element covered or encapsulated by particles the later being
dynamic.This produces two resistances, the element and the particle
skin. The element resistance goes to zero as the current flow moves
towards the surface thus removing skin penetration losses and where
all energy input is applied to propagation where we get accountability
for all forces resulting in an array or element where all is in
equilibrium without being planar as one must account for the earths
rotation vector as well as that for gravity otherwise equilibrium
cannot be retained. Thus as the diameter of the element is increased
so does the surface increase for the resting particles such that the
applied energy equals the energy required to elevate and propagate
the supplied particles. without penetrating the surface of the
element. This way we do not get into the situation of dealing with the
sharing of the total resistance and thus removing element losses that
do nothing for propagation, at the same time balancing the propagation
vectors upon the particles alone to the applied energy.
All basic classical physics which uses only fully accepted rules of
the masters without alteration of any kind as predicted by Einstein in
his search for the std model.