The point of minimum Z (that is, minimum magnitude of Z) will probably
be close to resonance. Resonance is the frequency at which the reactance
is zero. In a typical antenna near resonance, the reactance changes much
faster than resistance with frequency. This causes the magnitude of the
impedance, and the SWR, to be minimum near the resonant frequency. It
should be true for the antennas you asked about. It isn't true for all
antennas, however.

Roy Lewallen, W7EL

dansawyeror wrote:
Is minimum Z, across a frequency scan, 'resonance' on a 1/4 wave vertical?

Is it resonance on a center loaded vertical?

Thanks - Dan kb0qil