John Popelish wrote:
Standing waves have a current that
varies with position. The fact that the EZNEC simulation of a loading
coil shows differing current in a situation that is a fairly pure
standing wave situation (more energy bouncing up and down the antenna
than is radiating from it) means that the RMS current will vary along
the standing wave. And, since the simulation shows a different current
magnitude at the two ends of the coil, a significant part of a standing
wave cycle must reside inside the coil (more than the physical length
between the two ends of the coil would account for).

And since a significant part of a standing wave cycle resides inside
the coil, it occupies a non-negligible percentage of a wavelength.
By every valid method, measured or calculated, a 75m bugcatcher
coil occupies tens of degrees of a wavelength (out of 360 degrees).
My best estimate is 60 degrees in a 75m mobile antenna.

In one case (the highest frequency one) the phase of the current even
reverses from one end of the coil to the other, as well as an amplitude
variation, indicating that a standing wave node occurs some where inside
the coil, and the two ends are on opposite ends of that node. If the
two currents had been equal, but 180 degrees out of phase, the node
would have been in the center of the coil.

Yes, if a current node exists inside a coil, the standing wave currents
are flowing into the coil at the same time from both ends and 1/2 cycle
later they are both flowing out of the coil at the same time. Wonder
how a lumped-circuit inductance handles that? :-)
--
73, Cecil http://www.qsl.net/w5dxp