the Optibeam is designed NOT to be resonant... funny how that works. One
would think ALL antennas, if there is that likelihood, would be designed as
such or at least an optional kit. Especially since as you rightfully pointed
out: we don't all have unlimited or even substantial budgets ... I
personally realize compromises will be made and are inevitable - but I'd
like to make any that I do make based on knowledge and not out of either
ignorance (lack of knowledge) or fear.
g.
-----Original Message-----
From: john@kk9a.com
Sent: Thursday, June 2, 2016 3:02 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Modeling question - for the experts!
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@contesting.com>
Subject: Re: [TowerTalk] Modeling question - for the experts!
From: "Ed Sawyer" <sawyered@earthlink.net>
Reply-to: sawyered@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
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