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@att.net>
>Subject: [TowerTalk] 2 & 3 el 40m Booms
>To: towertalk@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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