On Fri, 25 Mar 2011 04:36:26 -0700 (PDT), Cecil Moore
wrote:

On Mar 24, 5:35*pm, "Richard Fry" wrote:
But if, as if you posted earlier, "a helical monopole is 90 degrees long at
the design frequency," are you claiming that such a short, self-resonant,
normal-mode, helical monopole has the same radiation resistance and system
performance as a self-resonant linear monopole of about 1/4 of a free-space
wavelength (other things equal)?

Absolutely not. I am claiming that a 1/8WL long *resonant* helical is
electrically 90 degrees long and has approximately the same radiation
resistance as a 1/8WL straight piece of wire. Radiation resistance and
linear *physical* length are correlated. Radiation resistance and
*electrical* length are NOT correlated. As I said previously
(concerning standing wave antennas) the feedpoint impedance is
associated with the electrical length of the antenna. Radiation is
associated with the physical length of the antenna.

Cecil,
You frequently embed comments in your posts that I find especially
important to antenna basics.

I am starting a list of Antenna Axioms with this:

"Radiation resistance and linear *physical* length are correlated.
Radiation resistance and *electrical* length are NOT correlated. As I
said previously (concerning standing wave antennas) the feedpoint
impedance is associated with the electrical length of the antenna.
Radiation is associated with the physical length of the antenna.
--
73, Cecil, w5dxp.com"

As a student of antennas I do appreciate your stating the basic
principals in answering questions.

There are a lot of Hams who still think a short resonate dipole is
just as good as a full size dipole.