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41. Re: [TowerTalk] trees and verticals (score: 1): Author: Jim Lux <jimlux@earthlink.net>; Date: Wed, 28 Dec 2011 12:20:56 -0800; Exactly.. and a scenario that is actually fairly easy to model with NEC. Just put a resistively loaded wire of appropriate properties next to the antenna and see how much current is in it. Let's say; /archives//html/Towertalk/2011-12/msg00742.html (9,283 bytes)
42. [TowerTalk] Trees and Verticals (score: 1): Author: "Dan Schaaf" <dan-schaaf@att.net>; Date: Wed, 28 Dec 2011 15:41:16 -0500; What happens if you make the vertical as a cage of vertical wires around the tree ? Joined at the top and joined and fed at the bottom. The tree is in the center of the cage. Cage wire antennas seem; /archives//html/Towertalk/2011-12/msg00743.html (8,151 bytes)
43. Re: [TowerTalk] Trees and Verticals (score: 1): Author: David Gilbert <xdavid@cis-broadband.com>; Date: Wed, 28 Dec 2011 14:05:04 -0700; That would be an interesting configuration to model in the manner that Jim Lux suggested (using a set of resistive wires to simulate the tree), but I'm pretty sure that the losses would be significan; /archives//html/Towertalk/2011-12/msg00744.html (9,791 bytes)
44. Re: [TowerTalk] trees and verticals (score: 1): Author: "Gary Schafer" <garyschafer@comcast.net>; Date: Wed, 28 Dec 2011 16:10:13 -0500; Google "waveguide beyond cutoff" and it will tell you why a signal will not get out of a steel building unless the opening is large enough. Many signal generators were built with variable attenuators; /archives//html/Towertalk/2011-12/msg00745.html (14,514 bytes)
45. Re: [TowerTalk] Trees and Verticals (score: 1): Author: "Dan Schaaf" <dan-schaaf@att.net>; Date: Wed, 28 Dec 2011 16:14:19 -0500; Let's go a step further, What happens if you put a dry wooden broomstick down the center of an aluminum tube vertical. Then a wet Broomstick. Best Regards Dan Schaaf K3ZXL www.k3zxl.com "Problems can; /archives//html/Towertalk/2011-12/msg00746.html (11,019 bytes)
46. [TowerTalk] trees and verticals (score: 1): Author: Roger Parsons <ve3zi@yahoo.com>; Date: Wed, 28 Dec 2011 13:35:12 -0800 (PST); Actually, it does make sense, but it is an incomplete statement. It was supposed to be. I will try to avoid any use of subtlety or irony in future. 73 Roger VE3ZI ____________________________________; /archives//html/Towertalk/2011-12/msg00747.html (7,545 bytes)
47. Re: [TowerTalk] Trees and Verticals (score: 1): Author: "Gary Schafer" <garyschafer@comcast.net>; Date: Wed, 28 Dec 2011 16:43:36 -0500; Again, see "waveguide beyond cutoff". No signal will ever get inside of the tube unless there is a conductor running out the opening to couple it in. then the signal will end inside shortly after rea; /archives//html/Towertalk/2011-12/msg00748.html (12,864 bytes)
48. Re: [TowerTalk] trees and verticals (score: 1): Author: "larryjspammenot@teleport.com" <larryj@teleport.com>; Date: Wed, 28 Dec 2011 13:45:48 -0800 (GMT-08:00); I agree. I've only gotten 291 countries with my Butternut HF6V on 40 Meters, and 241 on 80 meters with it. 5BDXCC and 5BWAZ. But no DXCC yet on 160M. Pretty pathetic! LJ --Original Message-- ________; /archives//html/Towertalk/2011-12/msg00749.html (12,523 bytes)
49. Re: [TowerTalk] trees and verticals (score: 1): Author: K8RI <K8RI-on-TowerTalk@tm.net>; Date: Wed, 28 Dec 2011 17:09:45 -0500; Probably not if it were made of dry wood. If really close to the antenna it would behave much like the plastic insulation/dielectric on a wire requiring the wire/antenna to be shortened a bit, but I; /archives//html/Towertalk/2011-12/msg00750.html (8,269 bytes)
50. [TowerTalk] trees and verticals (score: 1): Author: Roger Parsons <ve3zi@yahoo.com>; Date: Wed, 28 Dec 2011 14:10:53 -0800 (PST); There has been a great deal of going around the houses. The original question (and the one that I believe I answered) was related to the effect of trees. Wood is a poor conductor. Even wet wood is a; /archives//html/Towertalk/2011-12/msg00751.html (8,979 bytes)
51. [TowerTalk] trees and verticals (score: 1): Author: Roger Parsons <ve3zi@yahoo.com>; Date: Wed, 28 Dec 2011 14:18:10 -0800 (PST); 'The amount by which it would attenuate it would depend on factors such as size, material, thickness, frequency and so on.' It is certainly true that the attenuation could be very small. It is also t; /archives//html/Towertalk/2011-12/msg00753.html (8,353 bytes)
52. Re: [TowerTalk] Trees and Verticals (score: 1): Author: "Tom Osborne" <w7why@frontier.com>; Date: Wed, 28 Dec 2011 14:24:08 -0800; Had one here and it worked good. It was written up in QST or CQ some years ago. Had 4 55 foot wires going up the tree, connected to a ring at the bottom and the top, then threw out a 65 foot piece fr; /archives//html/Towertalk/2011-12/msg00754.html (9,787 bytes)
53. Re: [TowerTalk] trees and verticals (score: 1): Author: K8RI <K8RI-on-TowerTalk@tm.net>; Date: Wed, 28 Dec 2011 17:35:55 -0500; Yah, but it'd be good for the lumber industry. Unfortunately most of the wood coming through in the past few years is just about green enough that it'd sprout roots if you stuck it in the ground. <si; /archives//html/Towertalk/2011-12/msg00755.html (10,553 bytes)
54. Re: [TowerTalk] Trees and Verticals (score: 1): Author: Jim Lux <jimlux@earthlink.net>; Date: Wed, 28 Dec 2011 14:42:53 -0800; solid tube is different than a cage o' wires in terms of internal field. At some point, though, if you have enough wires, the cage will be identical to the tube. I'd say off the cuff that when the sp; /archives//html/Towertalk/2011-12/msg00757.html (9,348 bytes)
55. [TowerTalk] Trees and Verticals (score: 1): Author: "Roy K. Breon" <rbreon@rochester.rr.com>; Date: Wed, 28 Dec 2011 18:54:03 -0500; I remember reading an article in an Army publication from the signals group in Ft. Monmouth NJ which described a battlefield expedient antenna which used a tree as the antenna. They coupled to the tr; /archives//html/Towertalk/2011-12/msg00759.html (9,390 bytes)
56. Re: [TowerTalk] Trees and Verticals (score: 1): Author: David Gilbert <xdavid@cis-broadband.com>; Date: Wed, 28 Dec 2011 17:32:18 -0700; Well, I can say with pretty good assurance that a wooden pole, wet or dry, doesn't affect the currents flowing through a surrounding aluminum tube. The currents in the aluminum tube flow on the outsi; /archives//html/Towertalk/2011-12/msg00760.html (9,944 bytes)
57. Re: [TowerTalk] Trees and Verticals (score: 1): Author: Jim Brown <jim@audiosystemsgroup.com>; Date: Wed, 28 Dec 2011 16:54:45 -0800; Jim -- one of the variables in this antenna is the current distribution within the live tree, which will depend on the distribution of moisture within the tree. The significance of this is the relati; /archives//html/Towertalk/2011-12/msg00761.html (10,135 bytes)
58. Re: [TowerTalk] Trees and Verticals (score: 1): Author: K8RI <K8RI-on-TowerTalk@tm.net>; Date: Wed, 28 Dec 2011 20:01:36 -0500; I would think the tree on the inside would act like a leaky capacitor to ground. 73 Roger (K8RI) _______________________________________________ _______________________________________________ TowerT; /archives//html/Towertalk/2011-12/msg00762.html (10,744 bytes)
59. Re: [TowerTalk] Trees and Verticals (score: 1): Author: "Stan Labinsky Jr." <wa2puq@frontiernet.net>; Date: Wed, 28 Dec 2011 20:38:48 -0500; Interesting Gary, that you should mention this phenomenon. It is the reason that shafts connected to devices such as variable capacitors and roller inductors should be made of a nonconducting materia; /archives//html/Towertalk/2011-12/msg00763.html (10,751 bytes)
60. Re: [TowerTalk] Trees and Verticals (score: 1): Author: Jim Lux <jimlux@earthlink.net>; Date: Wed, 28 Dec 2011 18:18:31 -0800; That's an interesting question. The paper from the Italians actually was using electric resistance tomography (and radar) to look at exactly that: the distribution of water content within the tree. I; /archives//html/Towertalk/2011-12/msg00764.html (14,237 bytes)

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