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Re: [TowerTalk] 80m vertical ideas / questions

To: Towertalk <towertalk@contesting.com>
Subject: Re: [TowerTalk] 80m vertical ideas / questions
From: Tony Brock-Fisher via TowerTalk <towertalk@contesting.com>
Reply-to: Tony Brock-Fisher <barockteer@aol.com>
Date: Thu, 30 Dec 2021 08:09:23 -0500
List-post: <mailto:towertalk@contesting.com>
Paul-

My solution for 80m is a pair of phased delta loops as follows:

Each loop is an equilateral triangle one wavelength long. They are fed 1/4 wavelength from the top, which is fairly near a bottom corner. This gives vertical polarization. The apices are suspended about 65' above ground and the base legs run parallel about 6-8 feet above the ground. The apices are tilted inward and spaced 20 feet apart, supported by a PVC crossarm from a single tower. The base legs are spaced about 50 feet apart. They are fed as a phased pair, one driven and the other tuned as a reflector. I use a relay switching with a 1/4 wave matching section of 75 ohm coax to perform both the matching of the director and the tuning of the reflector (details on request). The antenna is switchable in 180 degree directions which for those of us in 1-land means EU and Sweepstakes.

The advantages of this antenna are:

1. Vertically polarized for good low-angle DX.

2. NO RADIALS NEEDED. The base leg acts as a radial, no need to get down on your knees all summer sewing radials into the lawn.

3. Gain like a 4-square in two directions.

4. Easily switchable between phone and CW. Just add a small (~13') stub to the middle of the base leg, running perpendicular to the base leg at the same height from ground to tune the loop down from phone to CW.

My guest ops love this antenna, and tell me I am loud on 80.

Sounds like you have enough height to make this idea work. Also it would be reasonable to try a single loop, which should work well by itself.

-Tony, K1KP

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