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Re: [TowerTalk] JK Mid Tri 15M Issue

To: towertalk@contesting.com
Subject: Re: [TowerTalk] JK Mid Tri 15M Issue
From: Jim Brown <jim@audiosystemsgroup.com>
Reply-to: jim@audiosystemsgroup.com
Date: Wed, 4 Sep 2024 16:15:38 -0700
List-post: <mailto:towertalk@contesting.com>
Jack's suggestion is a good one. If there IS interaction, what happens when disconnecting that feedline will strongly depend on the length of the feedline between the antenna and where you disconnect it.

Our contesting trailer for county expeditions and FD has the feedpoint for 80, 40, and 20 antennas within about 3 ft of each other. We run 500W from a KPA500 on each station, so we have double stubs on both the 40 and 80M feedlines, optimally placed on each feedline with respect to the antennas. That placement is discussed in great detail on my website, in a piece published by National Contest Journal, and with a pdf of slides for a talk I've done at Visalia, Pacificon, and to several clubs.

k9yc.com/publish.htm

When two antennas closely spaced antennas are related by their second harmonic, the lower frequency antenna can screw up the pattern of the higher frequency antenna. It so happens that the optimally placed stub nearest the antenna is also optimally placed to kill that pattern distortion!

73, Jim K9YC

On 9/4/2024 1:16 PM, john simmons wrote:
How about opening/shorting the 40M feedline whilst testing 15?


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