On Sun, 3 Apr 2005 08:17:48 -0700, "John Smith"
wrote:

I am looking for "Everything you wanted to know about a gamma-match--in a
nutshell."
In other words, what set of formulas would give you length, conductor
spacing, gamma capacitor value, ratio of gamma rod to driven element
diameter, and a starting measurement for the shorting bar between
conductors-- for a given frequency?

Hi Brett,

That question rather goes beyond the nutshell lead-in. However, for
the nutshell:
1/20th wave gamma rod;
capacitance about 5 to 8pF/Meter-of-wavelength;
gamma rod roughly half diameter as the radiator and spaced
roughly 1/100th wavelength from it.

With all the "roughlies" (a product of nutshell precision) it pays to
make the capacitor a variable, or the gamma loop length variable. All
such roughlies are also contingent upon the radiator's size WRT
wavelength.

To translate the capacitor characteristic:
for 20M band it would be 100 to 160pF

73's
Richard Clark, KB7QHC