Al, WA4GKQ wrote:
"---as frequency is increased past quarter-wave resonance, I`ve noticed
with interest that both reactance and resistance peak at different
times, as they increase with frequency toward the half-wave point."

At the end of the ARRL Antenna Book edoition 19 chapter on Antenna
Fundamentals is a bibliography which includes P.H. Lee`s "The Amateur
Radio Vertical Antenna Handbook". In my 1974 edition, there are Figs.
18(A) Vertical Antenna Base Resistance and 18(B) Base Reactance, versus
height in wavelengths.

Figs. 18(A) and (B) clearly show the variation of R and X just short of
1/2-wavelength and their dependence on the characteristic impedance of
the antenna.

If the "Antenna Book" doesn`t have the information, one of the
bibliography books most lilkely does.

Best regards, Richard Harrison, KB5WZI