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We use a balun or RF choke on our designs to isolate the outside of the shield of the coaxial cable from the antenna circuit. By not using a balun, you can expect reduction of F/B and skewing of the azimuth pattern. This pattern deformation can be demonstrated by modeling or by accurate field measurements. A C3SS without a balun or choke is not going to be operating at specification. It is very difficult to relate anecdotal observations to actual performance of the array as the environment needed to do this is usually not available. Nor do most "tests" use a reference antenna such as a dipole at the same height to compare performance. Your observations, though well intended, are just not supported by the science. As I've often said, build the antenna just as we say and it will do exactly what we say it will do! Not using a balun or RF choke will most definitely affect adversely the pattern and performance of any Force 12 antenna. I wonder why anyone would buy an antenna and not install a needed component such as the balun or RF choke. The added expense of a coil of cable (<$3.00) certainly should not be a barrier. 73 Natan W6XR Force 12 East Ithaca, NY FN12sk force12@qth.com ----- Original Message ----- From: <wa4dou@juno.com> To: <Force12talk@qth.com> Sent: Monday, January 15, 2001 1:37 PM Subject: Re: [Force 12 Talk] C-31XR Balun ... > Hello Frank and the gang, > While considerable debate still attaches itself to the whole subject of > baluns, i'd like to remind folks, especially those who run considerable > power and have one or more failures associated with their use, that it > has hardly been demonstrated that baluns are necessary in many instances, > despite the fact that the "benefit" of the use thereof is conducive to > near perfect theoretical performance in the mind of the user. > I have a F12 C3SS on a 53 ft. tower and have used it for nearly a year > without any balun whatsoever. During most of that time, i've had a Cal-Av > EB-1 balun which i intend to install in the Spring. Then i'll have a > "baseline" with which to judge the performance and necessity of using a > balun in my particular installation. So far, my impression of my antennas > f/s and f/b performance is consistent with the performance expectations > of a typical 2 element yagi. > I have had other yagis and quads with which i've sometimes used baluns > and sometimes not. I've even experienced 2 element yagi performance > (without benefit of a balun) that far exceeded theory on both f/b and f/s > in all directions. And i've definitely seen occasions where baluns were > desirable and did effect positive results. > That said, i'd like to encourage users and potential users to suspend > judgement and to evaluate their antennas, with and without and report > their findings in various appropriate forums. Efficiency dictates that > the simplest installation that achieves the desired result is always to > be desired. As a radio communications technician and ham of 39+ years, i > believe i'm capable of making accurate scientific observations in this > case. > 73 de Roy Lincoln WA4DOU > ------------------------------------------------------------------------- > ------------------------------------------------------------------------- > ----------------------------------------------------------------------- > > ________________________________________________________________ > GET INTERNET ACCESS FROM JUNO! > Juno offers FREE or PREMIUM Internet access for less! > Join Juno today! For your FREE software, visit: > http://dl.www.juno.com/get/tagj. > > > -------------------------------------------- > Force12Talk mailing list provided as a service by Force 12 Antennas, Inc. > Force 12 Web site: http://www.qth.com/force12 > > Submissions: send to Force12Talk@qth.com > To unsubscribe: send a blank e-mail to Force12Talk-leave@qth.com > Force12Talk Message Archive: http://www.qth.com/force12/list/force12talk > For problems with the list, contact n4zr@qth.com > > -------------------------------------------- Force12Talk mailing list provided as a service by Force 12 Antennas, Inc. Force 12 Web site: http://www.qth.com/force12 Submissions: send to Force12Talk@qth.com To unsubscribe: send a blank e-mail to Force12Talk-leave@qth.com Force12Talk Message Archive: http://www.qth.com/force12/list/force12talk For problems with the list, contact n4zr@qth.com |