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Subject: gamma's
From: (Dr. Richard W. Musicer)
Date: Wed, 15 Jan 1997 20:06:32 -0800
WE8W wrote: 
>hi all i have been designing a 2 el 20 meter yagi and wonder if anyone 
>can give me some pointers on a gamma match. layout shows a radiation 
>resistance of approx 35.8 ohms. i want to use 1/2 alum conduit for the 
>outer sleeve of the gamma but now i am really pulling my hair out 
>trying to figure out what to use for the inner rod and what type of 
>material to construct the capacitor material

Simple.  Just strip the shielding off the coax and shove the center 
conductor with the dielectric inside the 1/2 alum conduit.  'Capacitor' 
is adjusted by pulling the coax out (or further in) as needed.

HOWEVER....I don't like gamma matches anymore.  I have switched to the 
beta/hairpin/t-match system like hygain uses.  Better mechanically, 
easier to assemble, and the computer models it very well.  Try it 
instead of the gamma rod and you will never go back.

73/GL de Rick, N6CR

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