To: | towertalk@contesting.com |
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Subject: | Re: [TowerTalk] Breakall short vertical |
From: | Terry Conboy <n6ry@arrl.net> |
Date: | Fri, 11 Jun 2004 12:12:36 -0700 |
List-post: | <mailto:towertalk@contesting.com> |
Kintronic also has a link to a more theoretical IEEE article on this antenna: http://www.star-h.com/publications/ieee2002.pdf In the end, this is just a permutation of a short fat vertical with a large capacity hat. For short verticals, these work pretty well, but as Tom mentions, the ground currents are still relatively high, since the 4 wires all dump equal, in-phase currents into a common ground system. If you have 120 radials, the ground losses are quite small and the efficiency is good. If you have a more typical sparse ham ground system, the losses can be noticeable. I was surprised that the authors (PhDs, MSEEs, and PEs notwithstanding) of these papers don't seem to understand the realities of the ground currents. One of them also conspired to write another paper on folded unipoles that propagates the same mischief. http://www.dlr.com/dlrweb/papers/nabpaper/Nabpaper.htm Terry _______________________________________________ See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA. _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk |
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