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-----Original Message----- From: Randy Moody [mailto:w5rlm@arrl.net] Sent: Tuesday, July 23, 2002 4:18 PM To: 'Sylvan Katz' Subject: RE: [Force 12 Talk] C31XR & guy wire detuning ************************************************************************ *** Look on page 22-7 of Arrl Antenna Book. The readers digest version is that there is no single length greater than 14' that avoids resonance on all bands. There is also a chart that shows exact lengths for specific frequencies. I used Phyllistran and avoided the whole problem. It may be that it is cheaper and less time consuming in the long run. ************************************************************************ **** -----Original Message----- From: Sylvan Katz [mailto:jskatz@sk.sympatico.ca] Sent: Tuesday, July 23, 2002 2:48 PM To: towertalk; Force12Talk@qth.com Subject: [Force 12 Talk] C31XR & guy wire detuning Hello All I am trying to solve a guy wire problem - they seems to be detuning my C31XR. Last year when I installed the antenna I found I could not get the swr down to the spec level on 15 and 20. Natan suggested that I my guys could be detuning the XR. This summer I inserted insulators right at the top of the tower. This brought 15m right on spec! Great! I am still having problems on 20m - the minimum swr is about 400 khz too high. The bottom sections of each guy is about 54' long. Natan suggests that the capacitance caused by the insulators and subsequent following wire lengths can easily move the resonance of the 54' to a length near 62 feet which is nominally a full wave resonator on 20 meters. I want to break the 54' sections into two segments each. My question: What should the lengths of these two sections be to minimize their interaction with the C31XR? ... sylvan ps - please do not recommend the use of Phyllistran -- it is too costly to have it shipped here :) Ô¿Ô¬ ---------------- Sylvan Katz, VE5ZX Saskatoon, SK "A Novel Perspective of Amateur Radio Contesting" at http://www.dynamicforesight.com/~ve5zx -------------------------------------------- Force12Talk mailing list provided as a service by Force 12 Antennas, Inc. Force12 Web Site: http://www.force12inc.com To Submit Message to the List: Force12Talk@qth.com To unsubscribe and view the Message Archive: see http://qth.com/force12/list For problems with the list: contact n4zr@qth.com -------------------------------------------- Force12Talk mailing list provided as a service by Force 12 Antennas, Inc. Force12 Web Site: http://www.force12inc.com To Submit Message to the List: Force12Talk@qth.com To unsubscribe and view the Message Archive: see http://qth.com/force12/list For problems with the list: contact n4zr@qth.com |