Co-locating hf yagi and sat antennas

[ericr@access.digex.net (Eric Rosenberg)]

My satellite antennas (2m (10ft boom 7el x 7el) M-Square crossed yagi,
70cm G3RUH 16-turn, 10 ft boom helix, small s-band conifer dish) sit
comfortably on a 6 ft (2m) roof tower on top of my roof. 

I'd like to add a small HF beam (TA-33jr, TH3-jr) underneath the satellite
antennas. In addition to the physical spacing needed, do I need to space
the antennas any further apart? Should I put them perpendicular to
eachother? 

And what sort of reinforcement will I need to add to the roof tower? Is
guying the roof tower enough? 

Please email your responses and I'll summarize.

Thanks,

Eric WD3Q
Washington, DC
ericr@access.digex.net