[TowerTalk] Question on mast height above tower

K7LXC at aol.com K7LXC at aol.com
Wed Aug 21 17:48:15 EDT 2013


>  If you can find a copy of Dave Leeson's "Physical Design  of Yagi 
Antennas"
(out of print) he explains how to calculate all the moments  created by your
combination of wind speed, boom/mast lengths and material  types.  Then you
select the proper material, length and wall thickness  to withstand those
forces.  
 
        We used Dave's book  as a guide for our MARC Program (Mast, Antenna 
and Rotator Calculator). It's ten  bucks at  championradio.com.         
 
>  That stack sounds like a big load on the base of the 2"  mast, but
whether it will hold depends on the yield strength of the chrome  moly mast
you use.
 
        IMO most of the people that  buy expensive chromoly masts waste 
their money when there are other cheaper  alternatives available; e.g. SAE 
1026, DOM 520. There is a whole  chapter on masts in my UP THE TOWER book. 
 
        But in this scenario the  mast is beside the point. I'd say the 
tower won't take the local windspeed  conditions with the array that's being 
proposed. 
 
Cheers,
Steve     K7LXC
TOWER TECH


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