[TowerTalk] 40m OWA

donovanf at starpower.net donovanf at starpower.net
Sun Jul 27 12:21:16 EDT 2008


The boom design for a 40M OWA is highly dependent on local wind and ice loading conditions.  All of my Yagis are designed for at least 90 MPH wind with no ice, and at least 50 MPH wind with 3/4 inch radial ice.

While I do not have an OWA Yagi, the boom design for my full size stacked 3 element 40 meter Yagis may be adequate for your wind and ice conditions.  The additional OWA parasitic driven element, located near the middle of the boom, would have very little effect on the boom design.

My booms consist of two 24 foot lengths of 6061-T6 aluminum tubing, 0.188 wall thickness.  They're spliced together with a four foot length of steel tubing, machined to snugly (but not tightly) fit the inside diameter of the aluminum tubing after galvanizing.

My boom-to-mast mount is 12 inches square by 1/2 inch thick 6061-T6 aluminum plate.

The booms are guyed with 6700 pound Phillystran.


---- Original message ----
>Date: Sun, 27 Jul 2008 16:02:41 +0200
>From: "Peter Voelpel" <df3kv at t-online.de>  
>Subject: [TowerTalk] 40m OWA  
>To: <towertalk at contesting.com>
>I obtained a used 3 element yagi on a 39 foot boom which I am in the process
>of rebuilding.
>Since I have some boom tubing left from ny previous yagi ruined by Kyrill I
>think about an OWA design.
>Is there anywhere around with a good design on a 48 foot boom which seems to
>be proven length for that beam?
>EZNEC or AO files will be welcome.
>TowerTalk mailing list
>TowerTalk at contesting.com

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