[TowerTalk] ANTENNA SURFACE AREA VS ROTOR

[K7LXC@aol.com]

In a message dated 98-06-16 15:42:13 EDT, CATALANO_DENIS_E@hq.navsea.navy.mil
writes:

<<   In preparation for Field Day, I have a few wind loading questions 
      for the group.  The HD 73 has a spec of supporting an antenna with a 
      max surface area of 10.7 sq ft when it is tower mounted.  Does anyone 
      know what the figure is for mast mounted.  For the HAM IV, the figure 
      is half the tower mounted spec (15 vs 7.5 sq ft).  I wonder if half is 
      the general rule of thumb.  

      I would use the 50% derating for mast mounting applications. OTOH since
this is FD and it's only going to be up for 24 hours, you could probably get
away with somewhat more loading. Even if it fails, you can still turn it with
a rope. 
      
>>>   Last question is, would anyone care to guess what the surface area 
      would be for a 15M 6 element monobander on a 38 ft boom would be.  
      Estimates are OK.  >>
 
      Look in any manufacturer's catalog for something similar. It's probably
a 2 inch boom so just about anything similar will work. (I'm at work and don't
have my reference stuff here. OF COURSE I'm working.) It would only take you a
couple of minutes to calculate it too. Calculate the square footage and then
use a .67 multiplier to get the round-membered load. 

Cheers,  Steve  K7LXC

--
FAQ on WWW:               http://www.contesting.com/towertalkfaq.html
Submissions:              towertalk@contesting.com
Administrative requests:  towertalk-REQUEST@contesting.com
Problems:                 owner-towertalk@contesting.com
Search:                   http://www.contesting.com/km9p/search.htm