Art wrote:
"Normal mode helicals are commonly used on HF."

Yes. Such antennas include small diameter coils making up solenoids. The
turns act as small stacked loops.

A small loop acts as a short dipole but with its E and H fields
interchanged. See page 58 of the 3rd edition of "Antennas" by Kraus,
Marthefka, et al.

Best regards, Richard Harrison, KB5WZI