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.