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Total 7 documents matching your query.

1. [TowerTalk] Full-size 30m rotatable dipole has big swing in low SWR point (score: 1): Author: w5wz@w5wz.com; Date: Mon, 25 Oct 2021 09:03:15 -0500; Stepping back from the problem to see the entire forest, not the single tree....... I have built a full-size 30m rotatable dipole using parts from an old Telrex yagi. Taper from 1-1/4" OD to 5/8" OD.; /archives//html/Towertalk/2021-10/msg00184.html (7,985 bytes)
2. Re: [TowerTalk] Full-size 30m rotatable dipole has big swing in low SWR point (score: 1): Author: <john@kk9a.com>; Date: Mon, 25 Oct 2021 12:07:14 -0400; Did you model this? I believe the 468/Mhz formula only works on small wire dipoles. Telrex used through the boom element uninsulated elements so how did you feed this? Measuring the SWR near the grou; /archives//html/Towertalk/2021-10/msg00187.html (8,640 bytes)
3. Re: [TowerTalk] Full-size 30m rotatable dipole has big swing in low SWR point (score: 1): Author: Chuck Dietz <w5prchuck@gmail.com>; Date: Mon, 25 Oct 2021 11:24:49 -0500; I always thought the 468/f was for dipoles supported at the ends due to "end effect" Using 492/f gets you closer, but disregards the effect of the diameter of the tubing. Adjusting for that probably; /archives//html/Towertalk/2021-10/msg00189.html (9,565 bytes)
4. Re: [TowerTalk] Full-size 30m rotatable dipole has big swing in low SWR point (score: 1): Author: Ignacy Misztal <no9e@arrl.net>; Date: Mon, 25 Oct 2021 15:17:25 -0400; Must be some strange interaction, especially that SWR is high. JK Antennas recommend testing the antenna prior to installation a couple of feet off the ground, stating that resonances should be lower; /archives//html/Towertalk/2021-10/msg00190.html (9,895 bytes)
5. Re: [TowerTalk] Full-size 30m rotatable dipole has big swing in low SWR point (score: 1): Author: Jim Brown <jim@audiosystemsgroup.com>; Date: Mon, 25 Oct 2021 16:03:56 -0700; Good advice. Dipoles are fairly easy to model in NEC, which can take diameter and insulation into account. 73, Jim K9YC _______________________________________________ _______________________________; /archives//html/Towertalk/2021-10/msg00191.html (8,071 bytes)
6. Re: [TowerTalk] Full-size 30m rotatable dipole has big swing in low SWR point (score: 1): Author: w5wz@w5wz.com; Date: Tue, 26 Oct 2021 13:59:31 -0500; Thank you to all who replied and offered suggestions. I added 19 inches to each tip and it plays very well at ~45 feet above ground. --Scott, W5WZ _______________________________________________ ____; /archives//html/Towertalk/2021-10/msg00199.html (7,767 bytes)
7. Re: [TowerTalk] Full-size 30m rotatable dipole has big swing in low SWR point (score: 1): Author: W0MU Mike Fatchett <w0mu@w0mu.com>; Date: Mon, 1 Nov 2021 18:06:48 -0600; Did you model this with software and input the taper lengths etc? The Antenna will certainly look much longer close to the ground. Using the free space calculation of 492/Freq us about 24.2 ft per s; /archives//html/Towertalk/2021-11/msg00001.html (8,643 bytes)

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