You must have missed the announcement I posted not long ago. The article
about transmission line phasing systems ("The Simplest Phased Array Feed
System - That Works") is now available at
http://eznec.com/Amateur/Articles/. And there's also a new Windows
Simpfeed program which takes EZNEC (or other modeling program) reported
feedpoint impedances as its input (no mutual Z calculation necessary)
and calculates the feedline lengths necessary for proper phasing. Click
the Simpfeed link at that same URL to get it. It's considerably more
versatile than the older DOS programs. A short manual, including a
detailed example (using both the EZNEC demo and the standard EZNEC
program type), can be viewed by clicking the Help button in the program
window.

EZNEC example files CardTL.EZ and 4SqTL.EZ illustrate the results of
using this feed method. The new program does all calculations in double
precision, so you'll find the values it generates are slightly different
than the values in the example files -- they're actually better.

Roy Lewallen, W7EL

Cecil Moore wrote:
Years ago I experimented with two-element beams where both
elements were driven. Roy, W7EL, has some BASIC programs
on his web page that allows the calculation of phasing
harnesses for such antennas. The disadvantage is that one
must know the mutual coupling impedance between the two
elements.
. . .