On 4/18/2016 10:36 PM, John S wrote:
On 4/16/2016 1:01 PM, aria rangga wrote:
I was designed yagi that has lenght of the driven 0.16186 x 2 m and
the boom is 1.5 m. I plan to use hair pin match, but i still confused
about how we decided the lenght of hairpin and the looped coaxial ?
And when we can change the impedance while we use vwr analyser? I
have been using gama match and i measured the impadance while i
changing the lenght of the capacitor ( gama match)


If the impedance of each Yagi is 50 ohms (when in the stacked
configuration), you can attach a 1/4 electrical wavelength of 70 ohm
coax to each antenna, connect them to a T, and then attach your 50 ohm
main coax to the T. Like this...

75ohm 75ohm
Ant1--------- ----------Ant2
|
| 50 ohm feeder

Again, Ant1 and Ant2 are 50 ohms each.

By the way, if each Yagi is about 25 ohms each when stacked, you can use
50 ohm coax throughout.