[VHFcontesting] Yagis on masts

[Patrick Thomas]

Hey all,

I've been considering augmenting the park-and-go rover setup with a push-up mast.  However, I have noticed that the Rohn H50, etc., explicitly state that they are "not recommended" for use with yagis.  And sure, physics would suggest that if you have a 15' antenna boom, you are likely to have more off-axis "arm" acting on the top of the mast, versus a vertical or even a dish.  On the other hand, I don't know if they only say that to protect themselves against people who use H50s as semi-permanent rooftop installations in 80MPH wind zones with heavy ice.

So what's the verdict?  I'm sure it's "possible" but is it safe to use a large 2m yagi on an H50 when properly guyed, on a day with gentle breezes?  Or is it indeed "not recommended" under any conditions due to instability, etc?  For that matter, what about the weight of a rotor that high up?

(And yes, I'm still working on the halo stack, so worst case I could always hike that up the line... but would love to have the extra gain and directionality from the yagi.)

Thanks,

Patrick
KB8DGC