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## Wind area of mast.

 To: Wind area of mast. K7LXC@aol.com (K7LXC@aol.com) Thu, 5 Sep 1996 12:31:54 -0400
 ```In a message dated 96-09-05 11:40:14 EDT, you write: >I want to calculate the effective wind area of >a 2" diameter mast that is 72" long. > >Therefore 72" X 2" = 144 sq.in = 1 sq.ft. > >The calculation above would be accurate if the >mast were square. But because it's round >isn't there a constant I neet to multiply the >result by. Hi, Gene -- You're just about there. The round-member multiplier, or drag coefficient, is 0.67. It is used by Dave Leeson, W6QHS, in his book "Physical Design of Yagi Antennas", page 7-6. The EIA/TIA-222-F uses a 'reduction factor' of .51e(squared) + .57 where e is the solidity ratio. They also have an appurtenance force coefficient for a cylindrical appurtenance of 0.8 for an aspect ratio <7. You should investigate it further to look at the definitions and applicability to your question. This info is covered on pages 3-8 73, Steve K7LXC TOWER TECH -- professional tower supplies and services for amateurs ```
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