[TowerTalk] spacing of verticals on a temporary mast

[Patrick Johnson]

Group,
What is the rule of thumb or equation to determine the minimum spacing
between verticals on a temporary mast?  With Summer nearly upon us I will
be working bike races and other public service events.  I have a home brew
mast which extends to about 20 ft.  At the moment I've only run a 1/2 wave
2M vertical.  I would like to add a second vertical possibly another 1/2
wave 2M or a 1/4 wave vertical in the HF range.

Before I start building I want to make sure I start off with a long enough
cross piece to mount the verticals safely  and avoid interference and
cross-talk.

Thanks for the suggestions & input,

73s,

Patrick
KJ4TRT