MrBill2 - Note that impedance of Yagi is dependant too (and adjustable) by changing the distance between elements, and as the last method, by inclining the director in small angle (maybe 5...20 deg) ends toward mirror. Such manner is not difficult to get 50 Ohm out of typical 73 Ohm construction as I described here time ago this summer.

You are correct, and that is the reason that I suggested researching the designs available. And still, connecting to a yagi antenna that is optimized for gain or directionality may require a matching system. Even the best antenna requires correct matching to deliver the best performance.

 

MrBill2: As I told about my network analyser (N1201SA+) data over 868 MHz Yagi antenna I made this summer, the 1,1...1,15 SWR is available without of any matching circuit. However the bal-un is needed, thus I used the core-less solenoid wound of coaxial some 5 turns on 10 mm glass pipe, fixed by scotch. Worked well, as the touch of hand any point beyond was not changing any readouts, nor R, nor X, nor frequency plot in contrast of situation before that coil was applied.

 

Not all yagi designs present such a handy impedance, it depends on which parameter the design is optimized for.