[TowerTalk] Coaxial Moxon

[David J. Sourdis]

Thank you Dan, 

Interesting article and it says it all.

David  
HK1KXA
EC5KXA


Date: Sun, 3 Aug 2008 21:07:07 -0400
From: n3ox at n3ox.net
To: hk1kxa at hotmail.com; towertalk at contesting.com
Subject: Re: [TowerTalk] Coaxial Moxon

A quarter wave coax, shorted at the end shows an infinite impedance.Is it possible what is described in the link?

A coax just a little bit shorter than a quarter wave shows a VERY quickly changing inductive reactance ... so you can change the stub length +/- a few centimeters and find the exact value of reactance you need to load the antenna.


But, it's VERY lossy to operate a stub near resonance as a reactance.  I estimated something like Q = 1 or Q= 5 for the "quarter wave" (actually a little shorter) stubs in that antenna, and a model of it seemed to suggest that the gain would be *negative 10dBi* and it would have zero F/B ratio.


You might look at http://www.karinya.net/g3txq/coax_antennas/ as well.

73,
Dan 



_________________________________________________________________
Explore the seven wonders of the world
http://search.msn.com/results.aspx?q=7+wonders+world&mkt=en-US&form=QBRE