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21. Re: [TowerTalk] trees and verticals (score: 1): Author: David Gilbert <xdavid@cis-broadband.com>; Date: Tue, 27 Dec 2011 18:29:52 -0700; precisely because there is enough stuff up there to absorb a lot of the RF, although not all of it is wood. I don't think shingles are all that transparent to RF, for example, especially when wet. A; /archives//html/Towertalk/2011-12/msg00707.html (13,805 bytes)
22. Re: [TowerTalk] trees and verticals (score: 1): Author: N6FD <n6fd@hughes.net>; Date: Tue, 27 Dec 2011 17:56:44 -0800; Eddy, My answer to question #1 is that the wood in a building is usually dry. Dry lumber has much lower losses than wet lumber. Additionally, it only has to go through 3/4" to 6" of wood to get out a; /archives//html/Towertalk/2011-12/msg00709.html (12,702 bytes)
23. Re: [TowerTalk] trees and verticals (score: 1): Author: "Jamie WW3S" <ww3s@zoominternet.net>; Date: Tue, 27 Dec 2011 21:03:52 -0500; don't tell AC0C antennas in an attic wont work.... precisely because there is enough stuff up there to absorb a lot of the RF, although not all of it is wood. I don't think shingles are all that tran; /archives//html/Towertalk/2011-12/msg00710.html (10,168 bytes)
24. Re: [TowerTalk] trees and verticals (score: 1): Author: David Gilbert <xdavid@cis-broadband.com>; Date: Tue, 27 Dec 2011 20:45:47 -0700; Where did I say they won't work? I said exactly the opposite. They "work" even if they may be lossy simply because 1 or 2 S-units (or whatever the penalty may be) is still not that severe when compar; /archives//html/Towertalk/2011-12/msg00712.html (11,126 bytes)
25. Re: [TowerTalk] trees and verticals (score: 1): Author: K8RI <K8RI-on-TowerTalk@tm.net>; Date: Wed, 28 Dec 2011 00:15:04 -0500; I do agree about the trees unless the tree(s) are really close to the vertical. This is only one operator from two stations over 50 years which makes this pretty much anecdotal but for what it's wort; /archives//html/Towertalk/2011-12/msg00717.html (13,250 bytes)
26. Re: [TowerTalk] trees and verticals (score: 1): Author: "Jim Chaggaris" <jimc@pwrone.com>; Date: Tue, 27 Dec 2011 23:29:26 -0600 (CST); " A vertical is not a great antenna on 40m" Huh? Best Regards, Jim N9WW James Chaggaris PowerOne Corp./PowerOne Environmental 1020 Cedar Avenue Suite 203 St. Charles, IL 60174 Phn: (630) 443-6500 Fax; /archives//html/Towertalk/2011-12/msg00721.html (10,785 bytes)
27. Re: [TowerTalk] trees and verticals (score: 1): Author: Eddy Swynar <deswynar@xplornet.ca>; Date: Wed, 28 Dec 2011 08:27:08 -0500; would be smart to built an antenna inside of a steel structure when it would be better all the way around to put it in the clear. Why would you ever do that? --I guess you'd do it because, using the; /archives//html/Towertalk/2011-12/msg00724.html (11,963 bytes)
28. Re: [TowerTalk] trees and verticals (score: 1): Author: Roger Parsons <ve3zi@yahoo.com>; Date: Wed, 28 Dec 2011 07:50:38 -0800 (PST); Eddy and others I am a little unconvinced by some of the arguments that have been presented. Consider a Yagi in free space with nice copper elements. It would work quite well if one could find a way; /archives//html/Towertalk/2011-12/msg00726.html (9,462 bytes)
29. Re: [TowerTalk] trees and verticals (score: 1): Author: Frank <frankkamp@att.net>; Date: Wed, 28 Dec 2011 10:08:21 -0600; I am a LOT unconvinced. I was waiting for someone to finally figure out that the metal pole being discussed could actually be a vertical antenna. _______________________________________________ _____; /archives//html/Towertalk/2011-12/msg00727.html (8,441 bytes)
30. Re: [TowerTalk] trees and verticals (score: 1): Author: Rik van Riel <riel@surriel.com>; Date: Wed, 28 Dec 2011 11:36:47 -0500; I think I get it now... 1) If the element is very low resistance, the RF will induce a lot of current, but it will get re-radiated. 2) If the element is medium low resistance, the RF will induce a fa; /archives//html/Towertalk/2011-12/msg00728.html (10,488 bytes)
31. Re: [TowerTalk] trees and verticals (score: 1): Author: Jim Lux <jimlux@earthlink.net>; Date: Wed, 28 Dec 2011 08:54:46 -0800; You're describing the difference between the near field (wooden element in Yagi) and far field (propagating through a box). One would normally use a somewhat different analytical technique for the tw; /archives//html/Towertalk/2011-12/msg00729.html (10,426 bytes)
32. Re: [TowerTalk] trees and verticals (score: 1): Author: Jim Lux <jimlux@earthlink.net>; Date: Wed, 28 Dec 2011 09:00:52 -0800; Precisely right.... And that's really why soil properties are important. Really dry sand doesn't have much effect on radiation efficiency(it's your #3).. The proverbial salt marsh also doesn't (it's; /archives//html/Towertalk/2011-12/msg00730.html (11,414 bytes)
33. [TowerTalk] trees and verticals (score: 1): Author: Roger Parsons <ve3zi@yahoo.com>; Date: Wed, 28 Dec 2011 09:26:26 -0800 (PST); "You're describing the difference between the near field (wooden element in Yagi) and far field (propagating through a box)." Not really. The box could be in the near field or the far field (I know i; /archives//html/Towertalk/2011-12/msg00732.html (7,518 bytes)
34. Re: [TowerTalk] trees and verticals (score: 1): Author: David Gilbert <xdavid@cis-broadband.com>; Date: Wed, 28 Dec 2011 11:21:11 -0700; An element that is totally non-conductive introduces no losses because, as you say, no currents are introduced. An element that is perfectly conductive introduces no losses, but it does re-radiate an; /archives//html/Towertalk/2011-12/msg00734.html (11,125 bytes)
35. Re: [TowerTalk] trees and verticals (score: 1): Author: David Gilbert <xdavid@cis-broadband.com>; Date: Wed, 28 Dec 2011 11:27:30 -0700; What is there not to be unconvinced about? In that case, being conductive with presumably little loss, the vertical antenna if driven simply radiates RF ... or if not driven receives induced currents; /archives//html/Towertalk/2011-12/msg00736.html (9,587 bytes)
36. Re: [TowerTalk] trees and verticals (score: 1): Author: David Gilbert <xdavid@cis-broadband.com>; Date: Wed, 28 Dec 2011 11:42:14 -0700; EXACTLY!! How much current gets induced in an element made from any material is a function of it's physical shape, material properties (conductivity, dielectric constant, etc), proximity and orientat; /archives//html/Towertalk/2011-12/msg00737.html (11,464 bytes)
37. Re: [TowerTalk] trees and verticals (score: 1): Author: David Gilbert <xdavid@cis-broadband.com>; Date: Wed, 28 Dec 2011 11:49:23 -0700; That doesn't make sense. The ultimate lossy element is one that is conductive enough to accept power and resistive enough to dissipate it as heat. A totally non-conductive material is the ultimate no; /archives//html/Towertalk/2011-12/msg00738.html (7,320 bytes)
38. Re: [TowerTalk] trees and verticals (score: 1): Author: Jim Lux <jimlux@earthlink.net>; Date: Wed, 28 Dec 2011 10:59:43 -0800; But could change the pattern, because it changes the field distribution. (e.g. polyrod antennas and dielectric lenses in microwaves) An element that is perfectly The saving grace, for trees, I think,; /archives//html/Towertalk/2011-12/msg00739.html (10,083 bytes)
39. Re: [TowerTalk] trees and verticals (score: 1): Author: David Gilbert <xdavid@cis-broadband.com>; Date: Wed, 28 Dec 2011 12:16:55 -0700; Eddy, currents would remain on the INSIDE of the structure only and never escape the box. Look up "Faraday shield" if you don't believe me. If the steel structure was not fully enclosed you would, de; /archives//html/Towertalk/2011-12/msg00740.html (14,747 bytes)
40. Re: [TowerTalk] trees and verticals (score: 1): Author: David Gilbert <xdavid@cis-broadband.com>; Date: Wed, 28 Dec 2011 12:21:23 -0700; All true. I'm not even sure at this point, but I think the original message that began this thread discussed a vertical wire running alongside and in close proximity to a tree trunk, which would of c; /archives//html/Towertalk/2011-12/msg00741.html (10,943 bytes)

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