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problem. But I'll try to answer given the instrumentation limits (i.e. no anemometer). When the wind is perfectly calm, I measure 1.4:1 on the Nye Viking meter in the shack on 21.300. At wind speeds under 20 MPH (my best guess), the SWR varies from 1.2:1 to 2.2:1 with a period of 2 to 3 seconds which corresponds directly with the observed element motion and spacing variation of the driven elements (15/20 meter elements). On really windy days, it's worse in direct proportion to the wind speed. Because of the horrendous lightning in Florida, I don't play with antennas much in the rain. The antenna is essentially flat at 21.150 , rising to about 3:1 at 21.450 and 1.3:1 at 21.000. We made no attempt to trim elements at install time, just played with the parallel wire feed lines and hairpin coil to minimize SWR on 15 and 20. Other bands are not affected by wind. Tnx es 73, Hank AA4HP -------------------------------------------- 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 force12@qth.com |
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