Brian,
S22 is also useful and a Smith chart presentation would be desirable. But this would have less priority because the nanovna does not have the capability to measure it. Plus, you can always measure s22 by reversing your ports and measuring S11.
I dont know if the nanovna lacks the second directional coupler or the chipset has this limitation, but you can work around, for $70!
73,
Dean W8ZF
