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Re: [TowerTalk] Beta match adds capacitive reactance on 2 el Hy-gain 40m

 To: towertalk@contesting.com Re: [TowerTalk] Beta match adds capacitive reactance on 2 el Hy-gain 40m ? Steve Hunt Wed, 24 Oct 2012 15:06:27 +0100 mailto:towertalk@contesting.com>
 I forgot to say that the HyGain Beta match works out at about +j131 on 40m - that's much too high a reactance to be effective. It would transform the 22-j25 load to 32-j24. ``` If I were you I'd wind an inductor. 73, Steve G3TXQ On 24/10/2012 14:47, Steve Hunt wrote: ``````To transform 22-j25 close to 50 Ohms you need a shunt reactance of +j44 To transform 17-j24 close to 50 Ohms you need a shunt reactance of +j36 Hope that helps 73, Steve G3TXQ On 24/10/2012 10:21, DX Supply AB wrote: ``````Hello!! Has anyone an answer to this Beta Match behavior on a 2 el linear loaded Hy-gain DIS 7-2? I have assembled the antenna again after some years in the garage. I designed it for SWR min at 7040 kHz and measured up the Feed point impedance at 30 feet to Z=17 --j24 after having shortened the ```driver a little more ( about 1 ½ ") than what is said in the manual. In line ```with theory for a linear loaded design. Increasing height to 60 feet I ```assume change (according to Cebik) the Z to about 22 --j25 or so. Not much ```change. ```According to theory (and W4RNL Cebiks excellent paper on web) the only thing ```now needed to tune out the capacitive reactance of --j24 is to add an inductance of about 33 ohms. This can be done with a Beta match and I ```started using the Hy.gain Beta match supplied with the antenna (1/4" x 72 " rods spaced 2,4 " from the boom). This way final impedance ens up close to 50 ohms which is good. However, inserting the Beta match worsened the Z to 32,5-42 that is adding both resistance and capacitive reactance to the feed point impedance. How an earth can the reactance be more capacitive with an ```inductive Beta match over the feed point? Is the best thing to throw the beta match over board an build a small inductor coil of 33 ohms? Thanking in advance, Kari SM0HRP _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk `````` _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk `````` _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk ```
 Current Thread [TowerTalk] Beta match adds capacitive reactance on 2 el Hy-gain 40m ?, DX Supply AB Re: [TowerTalk] Beta match adds capacitive reactance on 2 el Hy-gain 40m ?, Steve Hunt Re: [TowerTalk] Beta match adds capacitive reactance on 2 el Hy-gain 40m ?, Steve Hunt <= Re: [TowerTalk] Beta match adds capacitive reactance on 2 el Hy-gain 40m ?, RMorris