[TowerTalk] Nesting of multiband stacked yagis

[Ian White, G3SEK]

Roger Rehr wrote:
>
>I want to have:
>
>       4       M2 12 el yagi           stacked for 144 MHz
>       4       M2 9 Lambda yagi        stacked for 432 MHz
>       4       M2 35 el yagi           stacked for 1296 MHz
>       1       Myers 3 x 2 slotted dish for 2400 MHz.
>
>
>
>I have been told that I could stack the 144 Mhz yagis in a 2 x 2 array
>approx 10 feet on a side,
>and then stack the 432 MHz antennas nested within that rectangle(70 inches
>on a side), and then stack the 1296 antennas within the 432 stack (28 inches
>on a side).  The dish would go "somewhere" (not sure yet where).

Take a look at my web pages, which contain an "FAQ" on this subject. 

The closest distance for stacking of mixed antennas depends on the
capture area of each antenna, which you can estimate from the
manufacturer's recommended stacking distances for two of the same
antenna.

I don't have the information from M2 so I can't comment further, but you
can judge the interactions by drawing the capture areas as ellipses on
squared paper or in a CAD program, and seeing how they overlap. For a
definitive answer, you have to model the whole nested stack using NEC-2.

Also, W1JR wrote about this problem in his VHF column in the old Ham
Radio (can anybody supply a reference or a reprint?).

As anecdotal evidence, I don't recall any truly successful 432MHz EME
station that is using nested stacking with 2m. 



73 from Ian G3SEK          Editor, 'The VHF/UHF DX Book'
                          'In Practice' columnist for RadCom (RSGB)
                           http://www.ifwtech.demon.co.uk/g3sek

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