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.