[TowerTalk] 15 meter beam on 40 meter tower ?

[john at kk9a.com]

Why would the 40m beam be effected by the 15m? It is unlikely that the 15m
beam will have much interaction from the 40m beam that is almost a
wavelength away but it is easy to model. If you have just one 40m Yagi, most
people put it near the top of the tower for lower radiation angle.

John KK9A 

Everett Jackson wz8p wrote:

Good Morning,
If I put a 5 element 15 meter beam 40 feet above
a full size 40 meter 3 element beam will they work ?

What would be the result ?   I have heard that both beams will suffer.
Best to ask before doing the wrong thing.   Do they need there own towers ?
73,
Everett - WZ8P