[TowerTalk] 2 & 3 el 40m Booms

[donovanf at starpower.net]

Dan,

It depends primarily on your ice and wind requirements.  Full sized 40M Yagis in Duluth, MN and Miami, FL require different boom materials than the same Yagis in Yuma, AZ.

At W3LPL, 3/4 inch radial ice and 100 MPH winds (at 200 ft elevation) are both expected (but not at the same time!).  My 3 element full sized 40M Yagis on 48 foot booms use 3 inch diameter booms with 0.188 wall thickness.  0.125 wall tubing would be adequate for 1/4 inch ice and 70 MPH winds (but not simultaneously!)

A 3 inch diameter boom with 0.125 inch wall would be an excellent choice for a full sized 2 element 40M Yagi, even in many severe ice and wind enviroments.

Full size 40M Yagi elements are a far more difficult problem, especially in severe environments.  But you didn't ask that question...

K7NV's Yagi Stress (YS) program does an excellent job in analyzing all of these problems.

73
Frank
W3LPL

---- Original message ----
>Date: Fri, 20 Mar 2009 07:44:50 -0700 (PDT)
>From: dan edwards <w5xz at att.net>  
>Subject: [TowerTalk] 2 & 3 el 40m Booms  
>To: towertalk at contesting.com
>
>what do people use for homebrew antennas with full-size elements?
>(besides tower sections!)
>
>digging in the scrap pile at W5WMU.
>
>thanks
>
>73 from texas, W5XZ, dan
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