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the VSWR dip. If you can find a dip of 1:1, then it's simply a tuning exercise for the T-bars or the loading coil. If the lowest VSWR dip (even outside the ham bands)is still showing a VSWR of about 2:1, then you know there is something wrong with the impedance. The Sigma series is designed to be 50 ohms. If there is something nearby like the tower that the Sigma is interacting with, the impedance will drop, causing the VSWR to increase due to a mismatch. Kenny K2KW --- Original Message --- From: Dino Darling <k6rix@earthlink.net> To: force12talk@qth.com Subject: Re: [Force 12 Talk] RE: Sigma 40XK >This is where having an antenna analyzer comes into play. While proximity >is surely an issue, haveing the analyzer will allow you to pick up the >antenna, move it around, step out of the near field, and take >readings. Its the best money you will ever spend! > >At 12:06 PM 11/07/2003 +0100, you wrote: >>Hello All, >> >>I just installed the Sigma 40XK on a wooden structure on my lawn close to a >>brick house and with the lower T-bar 7 feet (2 meter) up for the purpose of >>been able to walk on the lawn below it. The antenna is also just about 7 >>feet from a 18 feet tower (metal) with 4 x 6 elm for 2 meters. >> >>On 20 meters I have SWR 1:2.5 at the bottom of the band slowly rising to >>1:2.8 at the upper band limit. Is this what I have to expect being so close >>to other structures? Or do you have any suggestions? >> >>On 40 meters I spend some time fidling wiht the coils but could not get any >>resonable results that's why I resort to 20 meters. >> >>PS The manual says SWR 1:1.3 for 20 meters. >> >>Vy 73 >>OZ1CCM Kjeld >> >> >> >> >>-------------------------------------------- >>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 force12@qth.com > >Dino...k6rix@earthlink.net > > > > >-------------------------------------------- >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 force12@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 force12@qth.com |
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