[TowerTalk] CushCraft Query

[Jim Lux]

At 10:16 AM 6/22/2006, Kent Tiburski wrote:
>Changing the DE might give a different feed impedance, but as far as the 
>it changing the pattern , etc., it will still be the same.

I haven't actually tried it, and a well designed experiment beats pages of 
theory, but theory says that changing the impedance of any element changes 
the relative currents in the elements which changes the pattern.

The easy exception would be if the impedance change is due to some sort of 
broadband untuned matching device between feedline and feedpoint, like a 
transformer.

But if the matching device is reactive this would change the impedance that 
the element is "looking into" and that would change the currents among the 
elements too. Reactive matching networks are pretty common on single band 
antennas, for example a LC network, whether lumped or distributed(like a 
gamma match).  On a multiband antenna, who knows?

Jim..