[TowerTalk] Antennas down FOLLOWUP

K7LXC@aol.com K7LXC@aol.com
Tue, 12 Feb 2002 10:43:53 EST


In a message dated 2/12/02 5:48:03 AM Pacific Standard Time, 
majrabsr@rconnect.com writes:

> Closer investigation this morning leads to the following: 20M boom broke in
>  UPWARDS direction! Likewise, the 15M & 10M booms were bent UP. Broken
>  elements appear to have been broken sideways, based on the fact that I
>  installed the clamps toward the ground. I suspect something other than
>  ordinary wind and ice loading.
>  
    This is pretty common if you live on or near sloping terrain where the 
wind is driven UP the hill and hits antennas from underneath. That's when 120 
degree boom trussing is used. You've got a venturi effect going on where the 
windspeed is higher at the top of the hill than the apparent windspeed so 
they hardware really gets slammed in those conditions. 

Cheers,
Steve    K7LXC
Tower Tech 

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