Art Unwin wrote:
"I am still of the belief that on a fractional wave antenna the current
travels on both the outside and the inside of the radiator."

That`s so at DC but not at HF.

HF only travels on the outside layer of a conductor as more
current-opposing flux lines encircle the conductor`s center than
encircle the conductor`s surface or outer layer. See Fig. 2-10 on page
22 of Terman`s 1955 opus.

Art also is confused about current distribution on resonant antennas of
various lengths. Terman can help there too. On page 866 Terman wrote:
"The current distribution as observed in such a resonant wire (1/2-wave
open at both ends) serving as an antenna ordinarily approximates very
closely the distribution that would be obtained on the assumption of
zero loss. provided the wire length does not exceed 8 to 10 wavelengths.
The current distribution, accordingly has the character illustrated in
Fig. 23-3."
Also on page 866:
"----to a first approximation the current distribution can be taken as
that for a line with zero losses; it then has the characteristics
discussed in Sec.4-5."

Page 91, Fig. 4-3 shows the vectors (phasors) E1 & E2 at an
open-circuited load as happens at the antenna tips, Conduction current
ends at the conductor tip. Current interruption collapses the magnetic
field and induces an opposite current causing a zero sum current at the
tip, but the induced voltage is of the same polarity as the incident
votage making a voltage double at the antenna tip. Energy is conserved.

Best regards, Richard Harrison, KB5WZI