Gamma Matches are a very excellent means of matching 50 Ohm unbalanced
feed to a balanced feed antenna of lower feed impedance than that of
the feed transmision line.

Most difficulty with gamma matches comes when the feed point is below
1/4 lambda above ground. Ground and other reflections tend to alter
the feed point impedance and makes matching more difficult. Most
difficulty comes due to heigth above ground for the feed point and the
inability of the driven element being adjustable.

Depending on heigth of the feedpoint, the driven element and the gamma
match need itterative adjustments so that an acceptable match is
acheived.

james

On Sat, 03 Dec 2005 06:13:38 -0800, Jay in the Mojave
wrote:

+Hello jim:
+
+Yeah I had a problem tuning them also, no matter where I placed the
+Gamma Match Rod adjustments, it seemed to have a mind of its own. The
+Gamma Matches biting me again.
+
+Thats why the Gamma Matches will be lost for the Moonraker 6 rebuild.
+
+But after all that, yes it is a very impressive beam a antenna.
+
+Jay in the Mojave
+
+jim wrote:
+ Hey Jay, agreed the hubs of the PDLII are fragile. IMHO the tuning of
+ those ants is another drawback though when done correctly they operate
+ very well.