http://www.naic.edu/~angel/kp4ao/ham/owa.html
describes the underlying concept from W3FET -> use a fat element as the
driven element: fatter elements have increased bandwidth, but have
higher feedpoint impedance. But in a Yagi, the feedpoint impedance is
low (because of the coupling to the other elements, mostly.. it's sort
of a "parallel resistor" thing)
So, if you used a fat driven element, you get the combination of wider
bandwidth AND a feedpoint impedance that is closer to 50 ohms.
It's well known that putting another element close (<0.1 lambda) to a
dipole is electrically very similar to a fat element, and there you have it.
On 12/12/13 10:19 PM, Jim Thomson wrote:
Date: Thu, 12 Dec 2013 15:33:08 -0600
From: Kelly Taylor <ve4xt@mymts.net>
To: Steve Sacco NN4X <nn4x@embarqmail.com>, <towertalk@contesting.com>
Subject: Re: [TowerTalk] OWA Inventor?
## The OWA doesn’t use TWO driven elements. That was a KLM concept.
The OWA only uses ONE driven element... with the 1st director closed spaced.
I bought YO 4.0 when it 1st came out.....and it would not allow you to space
any
two elements any closer than .09 wavelength. Thus there was no way to arrive
at the
OWA design. Ditto with.... yagimax that came out aprx the same time.
## The late VE7WJ, Henry Thel, once gave a talk about the importance of using
close
spacing between the single DE..and the 1st director. That was back in the late
70s.
N6BT came out with OWA, direct 50 ohm fed monobanders for 20-15-10-6m
I think in the early 90s. Dunno who cooked up the original design, or which
software
they used, but the concept works superb. The OWA design has also been used on
hb 5-el,
20m monoband yagis , with great success.
## The F12 OWA, direct 50 ohm fed yagis are killer ants.
Jim VE7RF
Virtually every reference on Google searches to the Optimized Wideband
Antenna refers to WA3FET as the inventor. None refers to N6BT. Most also
co-credit K3LR for the OWA.
You might be able to outfox some Google search results, but not every single
one.
N6BT's contribution, which I don't mean to disparage, is a system to couple
multiple driven elements parasitically to eliminate traps in multi-band
antennas. He referred to them as multi-monoband arrays, since most of the
F12 antennas use discrete elements for each band of operation rather than
using traps to multipurpose elements.
The OWA, if I recall correctly, was around before Force12 was even a gleam
in N6BT's eyes. And, again IIRC, the OWA is a monoband antenna that uses TWO
driven elements and specific element spacing to provide consistent gain,
matching and F/B over a greater portion of a particular band than typical.
73, kelly
ve4xt
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