I think the advantage from a relatively low stack depends on the 40m beams.
A two stack of 2el beams with 1/2 WL spacing works fantastic and it is a big
improvement over a single yagi. When I modeled two OptiBeam OB3-40 3el
shortened beams at the same heights I did not see this same big improvement
over a single beam. I also modeled a stack of Moxon beams but do I not
recall the results. Anyway my NEC-2 engine does not properly model this
antenna so it's probably best not to comment on the stack pattern.
John KK9A
To: <towertalk@contesting.com>
Subject: Re: [TowerTalk] Takeoff angle
From: "StellarCAT" <rxdesign@ssvecnet.com>
Date: Mon, 24 Jul 2017 10:14:24 -0400
ah - sorry indeed BOP recommendation would be for 20 and above. From what I
understand stacking of 40's ... unless REALLY high and separated, doesn't
provide much other than the ability to change directions - one antenna one
way - the other another... at least when trying to 'stack' say 2 element
yagis at less than 150' top ... the bottom one doesn't provide a great deal.
Again: from what I've read - I've never had a stack on 40. No experience
here.
Gary
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