On 2/16/2013 1:31 AM, Sal wrote:
I'm building a yagi from the measurement tables the ARRL Antenna Book. I
have the driven element finished and getting a good SWRs with a home-made
gamma match.

I'm going to mount it on a wood 2 X 2 with as many directors as will fit on
an 8 feet boom.

Any advice? (I've already read that a gamma match is a poor choice but it
did work, so we can skip that one. :-)

"Sal"
(KD6VKW)



A gamma match will skew the pattern a bit but that's really nothing to
worry about.

The worry on a gamma match (and most matches) is where the impedance of
the driven element is low, where low is less than 20 ohms.

20 ohms is a number I like, others may like a different number. For
sure if you are down in the 10 or 12 ohm range you are in trouble.

T matches are better, but are more and less complex at the same time.
Personally I use gamma at 6m, both at 2m and T at 70cm.

tom
K0TAR