If anyone has an interest in modeling the V-Beam, I have placed a 4Nec2
input file at the top of my QRZ.com page. The Cartesian angle computation
allows for changing the included angle and leg length. Probably the easiest
way to save the file is to right-click on the link, then "Save Target As" to
your desktop.
To modify the file in 4Nec2, click on the main menu EDIT tab, then INPUT.
When the input menu opens, select the "Symbols" tab. Here, one can easily
adjust the antenna to any height, included angle, and leg length. The
default file has a 67 deg. angle and 350 ft. legs at 80 ft AGL, normal soil.
On 40m and 20m, be prepared to see an extraordinary result for a wire
antenna. As others have pointed out, quite a bit of land is needed along
with three high supports to get this level of performance.
https://www.qrz.com/db/W9AC
I'll leave the file up for a few days.
Paul, W9AC
-----Original Message-----
From: Patrick Greenlee
Sent: Thursday, September 17, 2015 7:15 AM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Has anyone every put up a V-beam?
Aluminum coated steel wire is commonly used for electric fences.
Although proper practice is to install it with low tension (as per
vendor and MFG) that is not because of any failing in the wire's
strength or resilience. It can take significant tension and last a good
long time. One issue is the skin effect. Your lowest frequency of
interest will penetrate into the wire to the greatest depth. You will
get better performance if your skin depth does not exceed the thickness
of the aluminum outer layer. I cant quote the formula for skin depth
from memory but it is readily available.
There has been a lot of this aluminum coated steel wire used for
antennas with good success.
Patrick NJ5G
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