"Wes Stewart" wrote :
Maybe part of the myth is that the antenna must be resonant to work.
Nothing could be further from the truth.

Can we agree that if the feedpoint impedance is purely resistive, then
the antenna is resonant?

How about this thought experiment: Assume a too short for resonance
monopole, that has its feedpoint impedance made non-reactive by the
insertion of a "base loading coil." All kinds of arguments, including
this one, arise about what the role of the coil is, what its current
distribution is, how it affects efficiency and so forth.

To minimize these arguments, let's stop calling the inductor a "base
loading coil" and call it part of an "L-network feedpoint matching
network." Now the radiator isn't resonant and the resulting feedpoint
reactance (and resistance) is matched separately with the external
network.

Has the radiator current distribution changed? No. Does the inductor
in the L-network "make up" some number of electrical degrees in the
radiator? Not from my viewpoint.

This can be easily addressed by looking at a G5RV on 40m. On
40m, the feedpoint impedance at the dipole is about 500+j100 ohms.
The parallel twinlead matching section is about 110 degrees long.
The resonant impedance looking into the matching section is about
27+j0 ohms. So the G5RV matching section has indeed made up
about 110 degrees needed by the antenna *system*. The tuned
matching section has increased the electrical length of the antenna
*system* by 110 degrees so its a pretty good match for coax.. The
same goes for an antenna loading coil no matter where it is located.
If the short whip antenna system needs 60 degrees to be matched
(resonated) the coil provides 60 degrees of phase shift.
That's all we are saying when we say the coil replaces 60
of degrees of an antenna system.

And the basic argument is whether a lumped circuit analysis
can be used on a coil when reflections are present. The answer
is NO!

If an antenna system needs 60 degrees to be resonant, it can be
done in any number of ways. You can give it 60 degrees of
transmission line or you can give it 60 degrees of coil. But please
note that the 60 degrees of phase shift in the loading coil has
no effect on the phase of the standing wave current. The phase
of the standing wave current essentially doesn't change all up
and down a 1/2WL dipole. Why would you expect it to change
in a shortened monopole. The fact that it doesn't changing is
essentially meaningless. It doesn't change whether a coil is
present or not.
--
73, Cecil, W5DXP