Hi
I think that this method of small circles centered with the renormalized impedance at the center of the Smith graph, must bring two advantages compared to that used by the DiSlord method:
1) we are rather in progressive wave and almost no standing wave, that is to say our area of ??interest during our antenna measurements close to SWR = 1.0,
2) secondo the measurements are rather made around the frequency of interest 14.100 Mhz a span of 4Mhz.
just it is desirable to have a graphic zoom of 8x of the Smith graph to further refine the value of Z0.
73s Nizar