[TowerTalk] Modeling question - for the experts!

[john at kk9a.com]

We all don't have unlimited budgets and space so we make compromises.
Actually all antenna systems have compromises. I have homebrew 15m beams
<20 feet above and below my lower 40m OptiBeam. I see no SWR change when
rotating and little pattern change on my model.  I have a couple of U.S
contest single band records on 40m and one on 15m, so it works to at least
some degree.  The OptiBeam is not resonant on 15m.  Personally I would not
use an antenna that was if it had to be on the same tower.

John KK9A



To:	<towertalk at contesting.com>
Subject:	Re: [TowerTalk] Modeling question - for the experts!
From:	"Ed Sawyer" <sawyered at earthlink.net>
Reply-to:	sawyered at earthlink.net
Date:	Thu, 2 Jun 2016 13:48:19 -0400

I believe that K3NA did some nice work on this subject that was published a
few years back in NCJ.  I don't remember the details, but I remember
concluding that you don't want your 40M beam and your 15 M beams on the same
tower if you can help it (mine are separated by 140 ft).  Also, that there
are lots of pattern distorting interactions on multiple yagis stacked on a
tower.  I have 4/4 on 20M with a 3 el in between facing south.  I am sure
that is not what I want to be doing and have though about removing it and
doing something else for 20M south.



Ed  N1UR