optimum stacking distance

[Zack Widup]

>
>At HamCom this past weekend I attended the antenna design forum on Sunday. The
>presenter (can't think who it was right now) stated that the optimum
>(vertical) stacking distance between Yagis was dependent on the gain of
>the individual Yagis.
>
>I had never heard of this before so when I got home I looked up Yagi
>Stacking in the ARRL Antenna Handbook. It briefly touched on this by
>stating that the stacking distance was dependent on the *beamwidth* of
>the major forward lobe and referred to a little graph with beamwidth on
>the x-axis and stacking distance on the y-axis. It showed that narrower
>beamwidth antennas must be stacked further apart than broader beamwith
>antennas.
>
>Now, I know that in general higher gain antennas have narrower
>beamwidths. Can someone explain why narrower beamwidth (higher gain)
>antennas must be stacked further apart? Or point me to a book that
>gives the details? tnx.
>
>
>73
>Kris AA5UO
>mraz at aud.alcatel.com
>
>
>
>

See the article "Stacking Yagis is a Science" in May 1985 HAM RADIO 
magazine, starting on pg. 18, by Steve Powlishen K1FO. 

Although the article is concerned with VHF/UHF antennas, the data applies 
just as well to HF CONTEST antennas.

There was also a 2-part article in HAM RADIO in April/May 1985 by Joe 
Reisert W1JR about stacking antennas.

Hope this helps!

					73, Zack W9SZ