I wish Tom was still on towertalk. I doubt that W8JI is using an off center
fed antenna when there are much better options. He describes the Windom on
his web site and states the following:
Loren G. Windom, ex- W8GZ, was instrumental in the development of the Windom
antenna. Loren lived in Reynoldsburg, Ohio. Loren was originally 8ZO from
Columbus, Ohio in 1922. His call is now reissued.
Windom's original idea was off-center feeding a horizontal antenna to
present a feedpoint impedance of 600 ohms. This is close to the surge
impedance of a single-wire feedline, allowing an inexpensive single
conductor to be used as a feedline.
In theory, with suitable selection of the feedpoint tap point and antenna
length, a reasonable match should occur on multiple harmonically related
bands.
The Achilles heel of the original single wire Windom is the single-wire
feeder. It has no "return conductor" or shield, so the single-wire feeder:
1) radiates and couples to everything around it. This causes TVI and RFI and
couples local noise into the receiver
2) causes considerable common mode currents along the feedline and at the
matching system. The common mode currents and strong electric field
extending a considerable distance from the feed wire causes RF grounding
problems and common mode currents in the Hamshack and on all the shack
wiring and equipment.
From:"Jim W7RY" <w7ry@centurytel.net>
Reply-to:Jim W7RY <w7ry@centurytel.net>
Date:Fri, 7 Jun 2013 09:17:45 -0700
List-post:<towertalk@contesting.com">mailto:towertalk@contesting.com>
-----Original Message----- From: Jim Brown
Sent: Wednesday, June 05, 2013 11:49 AM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Off Center Fed Antennas
On 6/4/2013 2:28 PM, Larry Loen wrote:
As long as we're talking OCF antennas, I've always found this an
interesting source as far as explaining them:
http://www.w8ji.com/windom_off_center_fed.htm
Yes. It should be noted that W8JI lives in the middle of nowhere, miles from
neighbors. I'm out in the country, but my nearest neighbors are about 500 ft
away, and I hear their noise.
No! He has a neighbor about 200 feet away from him... And many more down the
road. Please see a satellite view of his property.
73
Jim W7RY
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