On Dec 29, 9:11*am, Cecil Moore wrote:
Art Unwin wrote:
You never did supply the information needed to
justify the values of E,I and R when
*the current value crosses the zero line on a graph.

In simple terms, when the standing-wave current has
a zero amplitude at a current node, none of the energy
is in the magnetic field and all of the energy is in
the electric field. That's why a voltage maximum appears
at a current minimum. When the current equals zero, the
virtual impedance, E/I, is infinite.

This is essentially what happens at the end of a dipole
or monopole or open-circuit stub. The characteristic
impedance of a #14 wire 30 feet above ground is very
close to 600 ohms. Given that Z0, we can treat a dipole
element as a lossy transmission line and calculate the
voltage at the end of the dipole element.

If we model a 1/4WL 600 ohm open-circuit stub with
EZNEC and adjust the resistivity to 0.0000021 ohm-m
to simulate the radiation resistance of a dipole
wire, the feedpoint impedance of the stub is 35 ohms
and conditions on the lossy stub are very close to
the conditions on a dipole element.
--
73, Cecil *http://www.w5dxp.com

At the end of the radiator you state the energy is transfered to the
field
so I would imagine there is zero skin effect at that point and the
chain of
skin effect is still present on the outside of the radiator, this
because a full period has not yet elapsed
This equates to a displacement current across the capacitance gap
(plates) between
the outside and the inside of the radiator which is the only current
route available
when the capacitor field expires. Note that this energy is released
prior to the end of the current flow period
because of the absence of the skin effect at that time.
Cecil I am examining all the holy cows that pervade the science of
radiation
as it is universally accepted that radiation is not fully understood,
thus the many hats!
At the moment I see no mechanism that supports the capacitor field to
expire in the direction of incoming current
prior to the completion of the forward period.
Regards
Art