[Towertalk] ping-pong stacks

[Pete Smith]

At 04:03 PM 5/29/02 -0700, jimlux wrote:
>As a first order approach... use the phased array concept of pattern 
>multiplication ... Figure the pattern for two isotropic antennas fed in 
>the way you want, then multiply that pattern by the pattern of one 
>element.  This assumes two identical antennas, of course.. Given that one 
>is probably at the top of the tower and one is "next to" the tower, this 
>might not be a valid assumption.  You might try a simple model with just a 
>pair of dipoles (so that you get the polarization and images taken care of).

I'm wondering whether this really works, for stacks at HF, where the ground 
is a small number of wavelengths away?  It seems to me that identical 
antennas are far from it in that environment.

In any case, it is simple enough to model a small stack in NEC/EZNEC and 
alter the phasing to see what it produces.


73, Pete N4ZR

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