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

[RMorris]

Start over and do a search for K3LR and converting to a Moxon.

On Oct 24, 2012, at 5:21, "DX Supply AB" <kari at dxsupply.com> 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
> 
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