N4KG comments inserted below.
On Wed, 30 Jan 2002 "Rajiv Dewan, N2RD" <n2rd@arrl.net> writes:
>
> There are two ways a structure can withstand wind forces:
>
> 1. Be very robust (most of the older antennas, if they could survive)
> 2. Be compliant (like F12 antennas)
>
My Telrex 3L20 with 1.5 inch dia elements at center
is an example of #1. It weighs 75 lbs. I have one
assembled on a 10 ft waterpipe mast in the yard.
A *large* tree limb fell on the 3 inch OD boom,
bending the waterpipe mast. The Telrex antenna
was NOT damaged.
My old style modified Wilson 5L10's are an example of #2.
They use a 6 ft center piece 5/8 inch OD and 1/2 inch 5 ft tips.
Two END tips bent in high straight line winds. I 'assume'
they caught some 'flying debris' since the elements should
have been able to survive close to 100? mph winds (and
the intermediate element tips did survive undamaged).
Tom N4KG
> At least for tall skyscrapers, 2 is a better strategy.
> I think that it is the same for ham antennas too. The latter
> strategy leads
> to lower weight, turning moments, etc. A winning combination and
> better
> design in my opinion.
>
> Regards,
> Rajiv, N2RD
>
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