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[TowerTalk] EZNEC

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Subject: [TowerTalk] EZNEC
From: (Gary Myers)
Date: Sun, 07 Dec 1997 09:38:13 -0500
I am aware of issues related to verticals and dipoles - what to expect
and not expect. I expect and saw the dipole at ~1/2W had a lobe at 34
degrees, this looks right. Its elevation beamwidth is 41.5 degrees - its
azimtughal BW is 94.4 (@ 34 deg Ele).  I can see the vertical has
predominant low angle radiation - its main lobe is at 24 degrees with a
elev BW of 39.9 degrees. The vertical is modeled with 8 radials placed
3' above ground. The dipole is modeled at 30'. Everything at the moment
is at 14 Mhz. The problem I have is that the relative gain between them
is as such:

Dipole        Elevation Angle   Vert
-5.11           5               -6.62
0.53            10              -2.78
3.48            15              -1.21
5.23            20              -0.55
6.24            25              -0.40
6.73            30              -0.59
6.81            35              -1.05

Thus in all cases the dipole is stronger. Now I am aware of other issues
mainly considering polarization but I would think that if these RELATIVE
numebers were true the dipole, again at a lowly 1/2W, would enjoy a far
superior reputation than the vertical! At 15 degrees for example the
dipole is almost 5 db stronger!!! I suspect I am doing something wrong
with the modeling (again I just got this program yesterday). But I do
not know what!!!! The dipole model is what they start you with in the
examples - modified per the instructions in the manual. The vertical is
the vertical model they have with radials added. I can do just theirs
with no radials - i.e. no mods to the model, and I get max lobe at ~-3
db which seems right with no radials. 

So if we could concentrate on what I might have wrong in the model,
assuming these numbers above are indeed incorrect relative to each
other. If the numbers are correct then why is a vertical far superior to
a dipole at 1/2W. Is it strictly vertical vs. horizontal polarization??

tnxs, G.

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