[TenTec] OCF antennas evolution

[Rick - DJ0IP / NJ0IP]

Stuart, that is an excellent point (60% size = 90% efficiency) BECAUSE it is
exactly the kind of antenna that works great in small places, but has a low
impedance.  If you feed it with openwire, the last thing you want it to see
at the ATU is a 4:1 balun.

In fact, I have been running a vertical dipole (60% of full size) on 40m for
over 20 years.  It does not require radials.  In the beginning I burned up
several commercial high power 4:1 baluns until I figured out what was going
on and switched to 1:1 baluns.

In fact, I even ran that antenna on 80m all the time and consistently worked
the world with it in contests.  Not optimum of course but it is an antenna
that requires about 1 sq. ft. of horizontal space and is only 40 ft. high,
yet works all bands from 80 thru 10 - with a good tuner.

73
Rick, DJ0IP



-----Original Message-----
From: TenTec [mailto:tentec-bounces at contesting.com] On Behalf Of Stuart
Rohre
Sent: Friday, July 12, 2013 9:46 PM
To: tentec at contesting.com
Subject: Re: [TenTec] OCF antennas evolution

Wade and the group,

Wade's antenna is very close to the 135 foot doublet, and that has been
modeled and plotted by the late L. B. Cebik, whose collected antenna works
are at www.cebik.com.

He typically models the fundamental band based on the length of the antenna
and its patterns on all higher bands.

He also pointed out that a dipole only 60 per cent of a half wave at a given
band is still over 90 per cent efficient.

Stuart Rohre
K5KVH
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