Hi
below what i have measured on smith graph with my 25m length of RG213 coax cable with a NanoVNA H4
With Dislord function and no terminaison : it gives Z0=51.7 Ohm , it do not change with frequency's , based on low frequncy's measurement < 1.7 Mhz
with a 50.3 ohm resistor Coax terminaison, Smith graph gives a nice centered little circle for 53 Ohm renormalized impedance graph, ( 52 Ohm and 54 Ohm gives sheefted circles of center ) , 53 Ohm seems to be the good Z0 value for around 14.100 Mhz frequency's and not 51.7 Ohm as calculated by Dislord function,
This nice and relatively more accurate method need a 6X Zoom on smith graph , why not to add this option on the future H4 firmware ?
see sceenshoots attached
73's Nizar
