[TowerTalk] Fall Zones

[john at kk9a.com]

Plus it would be dangerous to be outside cranking down a tower during  
tornado or microburst and it may jam from the extreme side wind force.  
  I would not want to rely on having to crank down a tower to survive  
normal heavy winds however in hurricane prone areas crank-up towers  
may be good option. Most of the guyed towers that I know of in St  
Croix fell down during Hurricane Maria and most crank-up towers in the  
down position survived. Hurricane paths are predicted days in advance  
so there is plenty of time to lower a tower and even remove the  
antennas if desired.

73,

John KK9A - WP2AA



Bob KQ2M wrote

I don’t know how long is required to crank down at 89’ crank-up at  
full extension but I would suspect that it is at least 90 seconds.

At this qth, when a Tornado or macroburst/microburst winds are  
approaching, I get about 30 seconds warning from the oncoming “roar”  
of wind crashing through the trees.  The noise is loud, distinct and  
unmistakable.  If at that exact moment I started to crankdown an 89’  
tower, I doubt that it would have been lowered enough by the time the  
winds arrived to make it the rest of the way safely.  If it took me a  
minute or two to get to the station to lower the tower, I’m sure that  
it would be already too late.  That’s probably what happened with the  
guy with the tall tower, anemometer and winch.

The other issue with such violent winds is that they are usually  
hurling debris as they come in.  All it would take is one solid branch  
or piece of something wedging into the tower at a strategic spot to  
stop the winch dead in its tracks.  Game over for the tower.  BTW,  
this is one reason why Tornados are so dangerous – often significant  
damage is caused to objects  by debris picked up and hurled somewhere  
else outside of the funnel.


Bob KQ2M