[TowerTalk] Antenna Spacing

[Mike DeVivo]

I am considering putting up a 30 foot Universal tilt over tower. There would
be a 3 element HF Tribander and a mono band 2 meter and a mono band 440
beams. The VHF and UHF beams would be vertically polarized.
 
Universal recommends that nothing be 6 feet above the the tower. 
 
Other than physically speaking, I know about the 1/2 wave length guide line
of the lowest frequency. Does this apply only if another ham and I were
using two antennas on the tower at the same time or does this apply to the
function of a single antenna transmitting and some sort of over load
 
Thanks and 73,
Mike
 
N1CHP