[TowerTalk] Modelling a basic stack

[Pete Smith]

At 10:51 PM 5/9/2004, Bill Tippett wrote:
>         Bert, I would first use YO7 to optimize the
>antennas in their free space stacked configuration.
>YO7 already has the A50-5S in the database so it is
>simply a matter of selecting it and the stacking
>distance you want to try.  YO7 is still available
>and is supported by K6STI.  Brian can be reached at
>bbACn2.net where AC is the new Morse symbol for @.
>
>         Once you've optimized the F/R, Gain and SWR
>performance as a stack, you can then use N6BV's
>HFTA program included in ARRL's 20th edition of
>the Antenna Handbook to model different stacking
>heights over your actual terrain.


This raises a question.  I have always had the impression that antennas in 
an HF stack, even if first optimized in free space at the planned stacking 
distance, would be de-optimized (is that a word?) once returned to the 
"above ground" environment, because the ground plane also figures in the 
performance of each antenna, and the antennas are different distances from 
it.

True?

73, Pete N4ZR
The World HF Contest Station Database
was updated on April 26, 2004
2706 contest stations at
www.pvrc.org/WCSD/WCSDsearch.htm