I agree with John on the mechanical issues, but want to add one comment.
I have used tribanders about 10 feet from 40 meter beams and from my
experience there is little interaction...except on 15. You may see the SWR on
that band creep up somewhat....maybe instead of being 1.2, it may be 1.4.
However, that is a small trade off.
In a message dated 10/17/2014 4:16:32 P.M. Coordinated Universal Tim,
john@kk9a.com writes:
Putting the 40m beam on top has two benefits. Since it is the smaller
antenna there will be less mast stress and since it is a lower frequency
beam it should be higher. The tribander below it will have no effect on
the radiation angle.
John KK9A
To: <towertalk@contesting.com>
Subject: [TowerTalk] Stacking a 2L 40M and Tribander
From: "Marsh Stewart" <marsh@ka5m.net>
Date: Fri, 17 Oct 2014 10:04:56 -0500
My tower is a US Tower HDX-555. I'm planning to stack a compact 2L 40
monobander and a larger tribander on the same mast 10' vertically apart.
Which antenna should be on top?
The 2L 40M is lighter and has about half the wind load area of the large
tribander. So mechanically it should be on top. But, will it "shield" the
tribander and degrade its performance?
Marsh, KA5M
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