Jim Kelley wrote:
Cecil Moore wrote:

Could it be that a monopole is a "STANDING WAVE ANTENNA"?

The supposition is true, so the intended implication must be that only
standing wave current can be measured on monopole antennas. And Roy
therefore would have to have measured standing wave current (whatever
that is).

I must decline to agree. :-)

About 90% of the total current on an open-ended 1/4WL
monopole is standing wave current with close to unchanging
phase. That's why a 1/4WL monopole is called a "standing
wave antenna".

That is the current that Roy and Tom used so the component
traveling wave, accounting for about 10% of the total current
where the phase shift actually occurs, was mostly ignored and
swamped by the huge component standing wave.

This is such a simple concept - I don't see the problem
in understanding that a wave with the following equation
doesn't change phase with position (x). The phase is the
same over 90 degrees of length no matter what fixed x and
fixed t are chosen. EZNEC supports that fact of physics.
Here's the standing wave equation from "Optics", by Hecht:

E(x,t) = 2E01*sin(kx)*cos(wt) quoting "Optics", by Hecht:

"[Standing wave phase] "doesn't rotate at all, and the resultant
wave it represents doesn't progress through space - its a standing
wave."

Another interesting thing about the standing wave equation
is that the sign of (wt) can be reversed, i.e. standing waves
don't move in either direction - they just stand there. EM
waves cannot stand still so "EM standing wave" is an oxymoron.

Quoting one of my college textbooks, "Electrical
Communication", by Albert:

"Such a plot of voltage is usually referred to as a
*voltage standing wave* or as a *stationary wave*.
Neither of these terms is particularly descriptive
of the phenomenon. A plot of effective values of
voltage, appearing as in Fig. 6(e), *is not a wave*
in the usual sense. However, the term "standing wave"
is in widespread use."

From "College Physics", by Bueche and Hecht:

"These ... patterns are called *standing waves*, as
compared to the propagating waves considered above.
They might better not be called waves at all, since
they do not transport energy and momentum."

One can use EZNEC's VERT1.EZ to view the essentially
unchanging phase on a standing wave monopole. Just look
at the difference in phase between the feedpoint and a
point 45 degrees up the antenna. In 45 degrees of antenna,
the current phase changes by 3.65 degrees. That is the
current Roy used to measure phase shift through a coil
in order to support w8ji's 3 nS delay "measurements".
--
73, Cecil http://www.w5dxp.com
"Government 'help' to business is just as disastrous as
government persecution..." Ayn Rand