Richard Fry wrote:
"Cecil Moore"
A self-resonant coil is obviously 90 degrees long.

A coil is not the electrical equivalent of a linear, physical,
~90-degree, self-resonant radiator. How well do you expect your
self-resonant coil to radiate?

Not very well. Nobody is saying that a coil is a good
radiator. It probably radiates about as much RF as a
piece of wire of the same axial length as the coil.

Nothing about the discussion of phase
shift through a coil has had anything to do with radiation.
In fact, I have ignored radiation from the coil in all
of my calculations since I consider it to be negligible.

We have a phase shift in a transmission line with negligible
radiation. The same is true of a loading coil.

When you add a stinger to a coil, it is the stinger that radiates the
great majority of the applied power.

Absolutely no question about that. The round and round
design of a coil makes it more akin to a piece of
transmission line than it does to a radiator. But like
a transmission line stub, it contributes a phase shift
to the system.

The stub on a properly designed J-Pole doesn't radiate
much either. But one can certainly calculate the phase
shift from the feedpoint to bottom of the radiating element.

Again, the phase shift in the coil has virtually nothing
to do with how much the coil radiates. Looking at just
one turn on the coil, the current on each side of the
turn is approximately equal magnitude and flowing in
opposite directions (just as in a transmission line).
So virtually all the radiation is canceled by the
opposite near fields (just as in a transmission line).
--
73, Cecil http://www.qsl.net/w5dxp