Question to help my curiosity

[Oldme]

I will be the first to admit that my knowledge of antenna building and
theory is small.

In searching / reading I came across information building a helical antenna.
The inner working of a walkie talkie rubber duck enlarged, if you will.

The pictures I saw were for another band but it seems the same theory would
work regardless.

Are these efficient on a larger sale?
Say a 1/2 or 5/8 for 11 meter made out of 14 or 16 gauge wire for a vertical.
I can't remember seeing anyone talk about these. Of course there may be a reason
for that too.

What got me thinking:
http://www.smeter.net/antennas/short-helical.php
http://www.smeter.net/antennas/helical-modeling.php
http://en.wikipedia.org/wiki/Helical_antenna
http://www.k6mm.com/antennas/160M-QST.pdf

 

[Moleculo]

In searching / reading I came across information building a helical antenna.
The inner working of a walkie talkie rubber duck enlarged, if you will.
(snip)
Are these efficient on a larger sale?

No. They are about the most inefficient design possible. They do serve a useful purpose for when you need a small antenna, but that's about it.

Now, there is a type of directional helical antenna that is very useful for things like satellite work....

 

[Oldme]

Thanks.
Curiosity satisfied.