To measure 1/2 wave you could simply short the far end.
Sweep the frequency.
When s11 is -1 (impedance is zero) you're at the 1/2 wavelength frequency (or a multiple thereof, start the sweep very low).
You can learn all sorts of things by playing with a transmission line simulator. LTSpice is good.
(Unapologetic pitch for my stuff) SimSmith is better.
www.ae6ty.com/Smith_Charts.html
ward
