alhearn wrote:
"That is, when it`s too short for resonance, reactance is capacitive,
and is inductive if too long."

Just look at Terman`s phase diagram for a shorted transmission line and
I think you will agree with Capt. Lee.

Capt. Raul H. Lee, USNR, K6TS on page 31 of "The Amateur Radio Vertical
Antenna Handbook" wrote:
"The folded unipole feed principle may be easily applied to the short,
top loaded vertical radiator. The transformer action of the folded
unipole is used to give a more favorable input resistance than can be
obtained with a series feed. Another thing that the folded unipole feed
does is to reverse the sign of the input reactance. The input reactance
of a series fed tower shorter than 1/4 wavelength is always capacitive.
This means a series loading coil (spoken of in high power as a helix)
must be used to resonate the tower. With folded unipole input the feed
point reactance is always positive. (Consider the tower and feed wire to
be a shorted transmission line less than 1/4 wave long. Its input
reactance is positive.) Thus, the folded unipole may be fed with a
low-loss capacitive feed network.

Best regards, Richard Harrison, KB5WZI