"Bill VanAlstyne" wrote in message ...
Well, went back to the books and restudied the section on common-mode
currents on feed lines, and it appears that such currents are only caused
when a balanced driven element is fed with an unbalanced feeder. Since (if I
understand it correctly) the gamma match excites the driven element only on
one side, there is no way for the antenna to couple common-mode currents
into the feed line.

That said, I'm not sure I really understand how the gamma match works and
whether it represents a significant compromise. The Antenna Book doesn't go
into a great deal of detail about the gamma match, treating it basically as
a "subset" of the T-match. This, coupled with the fact that many amateurs
I've talked with unequivocally trash the gamma as a poor matching system
that should not be used where there is any choice, makes me want a better
understanding of this whole field.

So, the questions:

1) Is the gamma match inherently inferior to a balanced matching system?

Probably so to a degree, but I don't think it's enough to worry about
unless you have a specific problem with common mode currents. You have
to remember, the balanced T match has to be converted to the
unbalanced coax also. If not done properly, it could have problems
also. Most use coax baluns on those. To me, the higher the freq, the
more I would probably want to use a T over a gamma. On HF, where it's
really not that critical, I find gamma matches to be just fine here.
My 2 and 6 meter beams both use gamma matches, and I've never really
had any problems. But if I did, a choke at the feedpoint should clean
it up. As far as the gamma being a poor device that should not be
used, thats hogwash. 1000's have used those things with good results.
But this is not to say there aren't better methods to use. As far as
radiation from the element, as long as you have no common mode current
problems with either device, the end result is the same. MK