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(small band, high qrm from broadcaststations). New design of reflector frequency improved it a little bit in our 100 kc part of 40 m. Than got a EF140 and put it together with the EF240 on a new (own) boom, because there was no upgrade kit. Got the design frequencies (Mag340) from Nathan (thanks), but same as EF240 I was not happy with. Antenna design covers 300 kc of the band and when using only 100 kc as here in europe you do not get what would be possible. Computing a new design, I´m running the elements now on a boom of 11.55 m with new tuned parasitics. (antennaheight 17 m) (It runs very nice, always more than 1.5 s-units better than a 85 m double-zepp up 20 m) Now I started to put on the same boom 4 elements for 15 m. "boomlength" here about 9.55 m, that means 2nd director and reflector are just in1 m distance of the 40 m parasitics. Driver and first director in a distance of approxiately 1.5 m from the 40 m driver. Tuning the elements is just a hard job ! They are much longer than they should be and sometimes it is quite difficult to find the (right) resonant frequency. I would be interested in some comments about EF240 or MAG340. I do not know european users, if they have/ had also "problems" with F/b. Anyone tuned up the yagi to new frequencies ? Is there anyone who made some experience with (building) tuning duobandyagis ? 73 Frank, DL4KQ -------------------------------------------- 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 |
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