On Mar 31, 7:31*pm, John - KD5YI wrote:
Do you have an EZnec file you can post? I'd like to see what you're doing..

It is at:

http://www.w5dxp.com/helix.EZ

The 90 degree (1/4WL) resonant frequency is 10.067 MHz where the TOA
is 150 degrees.

The 270 degree (3/4WL) resonant frequency is 26.493 MHz where the TOA
is 155 degrees.

The difference in TOA is because of the two current maximum points at
26.493 MHz.

The 180 degree (1/2WL) resonant frequency is 16.6254 MHz where the TOA
is 29 degrees. Raising the single current maximum point from the
feedpoint to the midpoint of the helical monopole only moves it by
2.625 feet which is 0.0444WL (16 physical degrees) and that lowers the
TOA by one degree. Since the 1/2WL helical contains twice as much
wire as the 1/4WL helical, I don't see any advantage for the 1/2WL
helical over the 1/4WL helical except for the elevated current maximum
point which may require a less robust radial system.

The "Currents" button on EZNEC will display the current magnitude/
phase in the helical segments.
--
73, Cecil, w5dxp.com