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Re: Topband: Vertical dipoles in the real world

To: "Michael Armstrong" <armstrmj@aol.com>, <topband@contesting.com>
Subject: Re: Topband: Vertical dipoles in the real world
From: "Tom W8JI" <w8ji@w8ji.com>
Reply-to: Tom W8JI <w8ji@w8ji.com>
Date: Sat, 22 Sep 2012 08:54:15 -0400
List-post: <topband@contesting.com">mailto:topband@contesting.com>
A ringo ranger is a vertical half wave using "end feed" and they work
great.  I prefer end feeding, using hte method of the ringo (which is
easy to scale to other bands).  I purchased the 10 meter version some
years back and built ones for all bands to 20 meters by scaling the
end-feed arrangement.

When we end-feed a vertical like that, without radials, the system can have as much radiating current on the mast and feedline as the vertical itself has. This can do all sorts of things to the pattern and gain, because the feedline and mast become a major part of the actual antenna.

There is a basic electrical rule that cannot be broken. In order to force current up into the vertical at the feedpoint, an EQUAL current has to flow back down into the coax shield, the mast, radials, or something else.

We are kidding ourselves if we look at an end-fed antenna without a ground system and proper feed isolation and assume only the vertical is the radiator.

This is why, later in the Ringo's life, Cushcraft added a kit that added radials to the Ringo.

73 Tom
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