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[TowerTalk] Very long wire

To: <towertalk@contesting.com>
Subject: [TowerTalk] Very long wire
From: cebik@utkux.utcc.utk.edu (L. B. Cebik)
Date: Sat, 27 Sep 1997 07:31:25 -0400 (EDT)
> Anyway the point is we now have a really long wire.
> I intented to hook it up and play with it.  I was wondering 
> if any of the computer programs out there could model it 
> with any sucess and to see if anyone wants to give it a shot.
> 
> The poles are about 20' high and the telephone wires 
> are run either on each side of the poles or on some of 
> the run one above the other.  The wire runs WNW for about
> a mile and then at least another mile or more North. 
> 
George,

Did a couple of quick checks on the 10K' wire at 160 and 80.  These are
not definitive results since I need a lot more segments per unit length
for accuracy.  But as an initial ball park, here is what NEC gave me,
assuming the antenna is fed at one end and is 20' above ground.

Band     Gain    TO angle    Beamwidth
160      0.41 dBi   12 deg     21 deg
 80      4.36       10         17

Note the low TO angle.  There are no higher lobes to speak of.  Gain is in
the direction of the wire along the axis of the initial 5K' of wire within
1 degree.  F-B is 15-20 dB along the axis, with similar front-to-side
ratio.

I doubt anything would change much feeding 1 or both, but with this kind
of situation, try both and use the better.

If the model is pointing in the right direction (uncertain due to speed of
checks), you have a laser beam antenna for low band DX in the direction of
the wire from where you feed it.  Hope someone actually lives in that
direction.  Incidentally, the TO angles are those associated with
horizontal wires about 1.25 wl up, which is tough at 80 and 160.  Gain is
low, but QRM is also likely to be low with no high angle high gain lobes.

Now if your could only rotate the antenna.

This model is not fully proven, but the initial results may be an
indicator of general performance.

-73-

LB, W4RNL



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