On Tue, 24 Sep 2013 10:38:17 -0400, "Ralph Mowery"
wrote:

A few days ago I constructed a tape measure type antenna for 2 meters.
It is a 3 element beam and uses a hairpin or beta match.

Ran a return loss on it with the signal generator/spectrum analizer. The
best return loss was about 149 Mhz instead of 146. Thought it may be
because the tape AI used was 1/2 inch wide instead of 1 inch wide. I tried
lenghtning the hair pin form 5 inches to 6 inches. This did not change the
frequency of the return loss to any great ammount , but the RL went from
around 20 or more db to 10 db.

Did a little research on the hair pin match. From what I am getting out of
this, and it is very rough, is that the length of the driven element does
not make much differance in the actual resonate frequency of the antenna.
It is mostly where it is placed on the boom and the other elements that
determin the frequency of the antenna, but the length of the driven element
is determined by the impedance of the transmission line to be matched and
the impedance of the antenna/driven element.

Is that mostly correct or did I miss something in my reading ?



Look there before you waste too much time:
https://sites.google.com/site/tapemeasureantenna/


w.