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[TowerTalk] 2 el monobanders

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Subject: [TowerTalk] 2 el monobanders
From: k5ed@dzn.com (Ed Jensen)
Date: Tue, 19 Jan 1999 11:16:31 -0700
Hi,

I too had a TH3, but based on models and Steve's talk at Dayton went to a 2
el, but in a somewhat different manner.  I considered the C3S but cost drove
me to a semi homebrew solution.

I reasoned that the problem with trap beams was the narrow bandwidth of the
parasitic els (Steve's figures showed about similiar max gains available
from trapped beams but over a narrower BW), so I used monoband reflectors
(used Hygain's dimensions from their monoband beams) with the TH3 driven el.
I used a TH2 matching section.  I spaced all the reflectors .15 wavelgts
from the DE (appeared to be about max for a 2 el using MNjr and YagiMax).

Results for DX and contests are better than the TH3 so I guess gain is as
would be expected.  SWR readings (measured through 90 feet of RG8 foam and
MFJ259B) are:

14.00 1.8
14.12 1.1
14.29 2.0

21.00 1.9
21.19 1.0
21.42 2.0

28.0 1.4
28.3 1.0
28.9 2.0

Nice thing is low wgt (I calculate abt 25 lbs), no tuner required for 99% of
my operating, and cost was about $25 (I buy any used Hygain beams I come
across).

73, Ed

Ed Jensen, K5ED, El Paso, TX, k5ed@dzn.com



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