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21. Re: [TowerTalk] Elevated vertical (score: 1): Author: Ken <wa8jxm@gmail.com>; Date: Fri, 23 Dec 2011 17:46:57 -0500; Gerald, I disagree. If a quarter wave vertical or ground plane is lengthened to about .28 wavelength, the radiation resistance raises to about 50 ohms and a 1:1 SWR. It is not resonant, but it has a; /archives//html/Towertalk/2011-12/msg00578.html (9,974 bytes)
22. Re: [TowerTalk] Elevated vertical (score: 1): Author: TexasRF@aol.com; Date: Fri, 23 Dec 2011 20:18:59 -0500 (EST); Hi Ken, we have a differing definition of what constitutes resonance: You are talking about the radiating element only and I am talking about the radiating element plus everything else that constitut; /archives//html/Towertalk/2011-12/msg00582.html (10,911 bytes)
23. Re: [TowerTalk] Elevated vertical (score: 1): Author: <john@kk9a.com>; Date: Fri, 23 Dec 2011 18:10:33 -0800; I have never found this to be true so I did a quick model and EZNEC shows that a .28wl vertical has an SWR of over 3:1. Gerald, I disagree. If a quarter wave vertical or ground plane is lengthened to; /archives//html/Towertalk/2011-12/msg00584.html (8,107 bytes)
24. Re: [TowerTalk] Elevated vertical (score: 1): Author: Ken <wa8jxm@gmail.com>; Date: Fri, 23 Dec 2011 21:38:47 -0500; Okay, Gerald, I will agree that you and I are talking about different things. But most people talk about adjusting their antenna and saying it is resonant (or not) when they get a 1:1 SWR. As you hav; /archives//html/Towertalk/2011-12/msg00585.html (9,422 bytes)
25. Re: [TowerTalk] Elevated vertical (score: 1): Author: "Paul Christensen" <w9ac@arrl.net>; Date: Fri, 23 Dec 2011 22:36:13 -0500; How are you defining the terms "tuned," and "matched?" What is tuned and what is matched? How is your use of "tuned" different than "resonant?" Your antenna in this example is not resonant at the an; /archives//html/Towertalk/2011-12/msg00587.html (10,962 bytes)
26. Re: [TowerTalk] Elevated vertical (score: 1): Author: Grant Saviers <grants2@pacbell.net>; Date: Fri, 23 Dec 2011 19:49:25 -0800; Tom, Back to your question - you should declare VICTORY! The wide bandwidth may be due to the various lengths and/or couplings of the elevated radials. There is nothing to indicate you have high loss; /archives//html/Towertalk/2011-12/msg00588.html (10,136 bytes)
27. Re: [TowerTalk] Elevated vertical (score: 1): Author: "Paul Christensen" <w9ac@arrl.net>; Date: Fri, 23 Dec 2011 22:50:33 -0500; Incidentally, the 160m "T" I discussed below was deliberately resonated to 1.4 MHz -- not to 1.8 MHz. At 1.4 MHz, Z was 85+j0. At 1.8 MHz, Z was 50+j200. A low-pass L network then transformed that va; /archives//html/Towertalk/2011-12/msg00589.html (12,286 bytes)
28. Re: [TowerTalk] Elevated vertical (score: 1): Author: Al Kozakiewicz <akozak@hourglass.com>; Date: Sat, 24 Dec 2011 00:08:28 -0500; Maybe a nit, or maybe not, but transmission line VSWR is determined solely by the ratio of the characteristic impedence of the feedline to the antenna feedpoint impedence. Adding a matching circuit a; /archives//html/Towertalk/2011-12/msg00590.html (12,972 bytes)
29. Re: [TowerTalk] Elevated vertical (score: 1): Author: K8RI <K8RI-on-TowerTalk@tm.net>; Date: Sat, 24 Dec 2011 00:17:14 -0500; It's been my understanding that a simple wire antenna, or vertical doesn't care if it's resonant or not, nor does the antenna care if it's reactive or not. You tune out the reactance and match the im; /archives//html/Towertalk/2011-12/msg00591.html (8,880 bytes)
30. Re: [TowerTalk] Elevated vertical (score: 1): Author: Al Kozakiewicz <akozak@hourglass.com>; Date: Sat, 24 Dec 2011 00:30:42 -0500; That's my understanding as well. You can't ignore VSWR altogether, however. There are a couple of considerations: 1. Many, maybe most, hams that understand changing transmission line lengths helps ef; /archives//html/Towertalk/2011-12/msg00593.html (10,256 bytes)
31. Re: [TowerTalk] Elevated vertical (score: 1): Author: TexasRF@aol.com; Date: Sat, 24 Dec 2011 08:52:44 -0500 (EST); Hi Ken, the statement in the Antenna Book about the waves on the radiator bouncing back and forth and being reinforced by the next wave to achieve resonance is exactly right. But, the point where one; /archives//html/Towertalk/2011-12/msg00594.html (11,061 bytes)
32. Re: [TowerTalk] Elevated vertical (score: 1): Author: "Mike Ryan" <mryan001@tampabay.rr.com>; Date: Sat, 24 Dec 2011 09:17:48 -0500; Gerald is correct here. I think one has to start with the feed line. IF W7WHY wants his antenna resonant at 7.125 it might be in his best interest to find out what the velocity factor is for his coax; /archives//html/Towertalk/2011-12/msg00595.html (12,724 bytes)
33. Re: [TowerTalk] Elevated vertical (score: 1): Author: Hank Garretson <w6sx@arrl.net>; Date: Sat, 24 Dec 2011 07:10:16 -0800; On Fri, Dec 23, 2011 at 9:08 PM, Al Kozakiewicz, AB2ZY <akozak@hourglass.com Maybe a nit, or maybe not, but transmission line VSWR is determined solely Another nit. And, also by loss in the feedline.; /archives//html/Towertalk/2011-12/msg00596.html (9,324 bytes)
34. Re: [TowerTalk] Elevated vertical (score: 1): Author: "Paul Christensen" <w9ac@arrl.net>; Date: Sat, 24 Dec 2011 10:38:20 -0500; Sometimes VSWR does change significantly along a line -- and not always for reasons of loss nor common-mode RF current on the outside of a coaxial line. Consider this example: At the operating frequ; /archives//html/Towertalk/2011-12/msg00597.html (9,997 bytes)
35. Re: [TowerTalk] Elevated vertical (score: 1): Author: Jim Lux <jimlux@earthlink.net>; Date: Sat, 24 Dec 2011 08:09:31 -0800; This is the classical resonance condition for a resonant system (e.g. mass on a spring, single RLC). Where we get wrapped around the axle is when we try and use a RLC conceptual model for an antenna.; /archives//html/Towertalk/2011-12/msg00598.html (12,009 bytes)
36. Re: [TowerTalk] Elevated vertical (score: 1): Author: Ken <wa8jxm@gmail.com>; Date: Sat, 24 Dec 2011 11:15:43 -0500; Paul, I think you forgot to differentiate between the actual SWR and what a meter may read ;-) Just because a meter says the SWR is 5:1, doesn't necessarily mean it is so. A meter at different points; /archives//html/Towertalk/2011-12/msg00599.html (11,564 bytes)
37. Re: [TowerTalk] Elevated vertical (score: 1): Author: "Tom Osborne" <w7why@frontier.com>; Date: Sat, 24 Dec 2011 08:32:08 -0800; Hi Mike Never said I was worried about it. In fact, I said it was working good. I was just curious why it would have a double dip. Merry Charismas to all. Tom W7WHY /listinfo/towertalk ______________; /archives//html/Towertalk/2011-12/msg00600.html (8,602 bytes)
38. Re: [TowerTalk] Elevated vertical (score: 1): Author: "Paul Christensen" <w9ac@arrl.net>; Date: Sat, 24 Dec 2011 12:35:26 -0500; Not needed. Nor is any math involved in reaching the correct answer. So, which is the correct answer? If math or a 600-ohm VSWR meter is needed to answer the question, then the concept isn't underst; /archives//html/Towertalk/2011-12/msg00608.html (10,973 bytes)
39. Re: [TowerTalk] Elevated vertical (score: 1): Author: Al Kozakiewicz <akozak@hourglass.com>; Date: Sat, 24 Dec 2011 12:35:47 -0500; Sigh... This wasn't meant to be an exercise in ignoring the context! I'm talking about a single feedline with a uniform characteristic impedence and resonable loss, with reasonable defined as a level; /archives//html/Towertalk/2011-12/msg00609.html (11,259 bytes)
40. Re: [TowerTalk] Elevated vertical (score: 1): Author: <john@kk9a.com>; Date: Sat, 24 Dec 2011 10:07:32 -0800; The measured impedance will change depending on the length of the coax. It should match the antenna feedpoint impedance at 1/2 wavelength multiples. The SWR should not change with coax length, except; /archives//html/Towertalk/2011-12/msg00610.html (9,437 bytes)

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