In a message dated 96-02-09 02:14:21 EST, you write:
>Although I agree with your statements that crankups are not capable
>of the holding as much wind load as a guyed tower, the fact of life
>here in Los Angeles is that there would be no towers if it weren't
>for crankups. I don't know of a guyed amateur tower within the LA
>city limits. Most of us don't leave them fully extended during windy
>conditions. And like many hams, some have seriously overloaded
>them. On the other hand, I'm always amazed at the number of
>antennas that some hams stack on Rohn 25G. In fact as I recall the
>cover of CQ featured the results of K1EA overloading his 25G
>installation (it was shown bent over).
>
>73 de Bruce, WA7BNM (bhorn@netcom.com)
Bruce --
Thanks for your input. Yes, crankups are sometimes the only solution in
some places/situations. And again, if you follow the manufacturer's specs
you're system will be reliable. I think that the same situation exists in
Japan, I've never seen a picture of a guyed tower in Japan - just crankups or
self-supporters. Some crankup owners leave their towers cranked up and say
that they'll crank them down when a wind comes up. First of all, you're not
always at home when some storm comes up and secondly, unless your tower has
positive pulldown, it won't crank down because of wind pressure on the
sections anyway. The ones that I've installed with motorized positive
pulldown (such as US Towers) are really elegant - and expensive!
Rohn will tell you that the number one cause of tower failure
(particularly amateur), is overloading -- surprise! I think that it was Doug
Grant, K1DG, on that cover of the fallen tower -- the old maxim 'if it
doesn't come down, it's not big enough' isn't appropriate anymore.
73, Steve K7LXC
"Up The Twoer" now appears in CQ Contest magazine
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