Amos Keag wrote:

Resonance has NOTHING to do with impedance. Resonance is resonance; it
has a harmonic response.
. . .

Resonance has everything to do with impedance. Resonance is defined as
any frequency at which the impedance is purely resistive; that is, where
the reactive part of the impedance is zero. And that is all resonance is.

You can change the resonant frequency of an antenna by simply adding a
series or parallel inductor or capacitor at the feedpoint. This doesn't
change the antenna characteristics in any other way than to alter the
feedpoint impedance.

Roy Lewallen, W7EL