[Antennaware] helically wound dipole

[Drax Felton]

I searched Google for "Helically Wound Antennas" and found plenty of
articles for helically wound monopoles and verticals. Same with the ARRL
antenna book. 

Is there such a thing as a helically wound dipole? I know people have made
Hamstick dipoles, which are helically wound, correct?

I am considering experimenting with a mobile dipole for 20m or 40m that is
physically short (1 to 8 ft.), horizontally polarized, and is a balanced
antenna that is continuously loaded without the use of loading coils other
than the helix itself. The idea is to work NVIS mobile.

I am not looking for wide band operating range. I have an automatic antenna
tuner, but I only want to operate on the PSK31 spot frequencies, so self
resonant is better.

Any ideas?

Where I can find the calculations for the number of turns per unit of
length?