Topband: 1/2 wl verticals and spaving

[Tom W8JI]

I'm glad to hear that it's that simple.  I used the same principle when the 
verticals were dedicated to 40M and were 1/4wl tall where I fed them with 
3/4wl and 5/4wl coaxial runs.  The gain and side nulls were impressive.>>>

Carl,

This is real simple to handle.

With a 1/4 wave or odd 1/4 feed to a current-fed vertical, the feedline 
needs equal voltages at the phasing unit to force equal currents. If it was 
a 1/2 wave feeder, it would require equal currents.

With a voltage fed antenna and a 1/4 wave feeder to the phasing unit, it 
would require equal currents at the phasing unit. If you make the feeder to 
each vertical 1/2 wave long, then it takes equal voltages at the phasing 
unit just like a normal current fed does with 1/4 wave feeder.

The issue with this is transmission line properties in the matching system 
at the vertical can upset what you think is the transmission line length.

With the 1/2 wave wide spacing you really only have the choice of in or out 
of phase for any pattern with deep nulls, so none of this really matters. 
Each element would have the same impedance.  If you had a unidirectional 
pattern it would matter.  I probably would just run a catenary line between 
the towers and drop a pair of wire elements for 40. If the verticals would 
support that, then you could get a unidirectional end fire pattern with 40M 
elements.

At 1/2 wave spacing, you are kind of stuck with limited patterns with very 
modest gain and no unidirectional pattern.