Topband: 1/2 wl verticals and spaving

[Carl Braun]

Topbanders

Im currently using a two element vertical array that I'm able to use on both 80 and 160M by switching in two different feedlines and matching schemes.  The system works well using a Comtek switch box on 80 with the verticals spaced at ¼ wl and the classic Christman method of feeding the verticals on 160 via 157 deg feedlines and 37 deg delay line.   Using the same vertical elements results in 1/8 wl spacing on 160.

On last challenge I want to tackle is using the same verticals on 40M.  The elements would then be effectively spaced ½ wl apart and would be ½ wl tall.

I cannot find any patterns or phasing suggestions for this arrangement...only ¼ wl radiators.  Can anyone offer any suggestions for feeding an array like this on 40M?

In the past I use the same verticals for 40m but they were only 33' tall and I fed it in and out of phase using the Christman coaxial delay line technique and it worked well...however, my elements are now 65' tall and all the math surely changes.

Any suggestions or websites available on ½ wl spacing and ½ wl radiators?

Thanks

Carl AG6X