NanoVNA setup for common antenna system measurement tasks showed a display configuration better suited to those tasks.
It is tedious to set the display up using the device menu, and setups may vary with different NanoVNA hardware and firmware.
The firmware I used was NanoVNA.H.v1.2.20 which allows some setup using serial port commands. This article describes the technique.
The command used is the trace command
trace {0|1|2|3|all} [logmag|phase|delay|smith|polar|linear|swr|real|imag|r|x|z|zp|g|b|y|rp|xp|sc|sl|pc|pl|q|rser|xser|zser|rsh|xsh|zsh|q21] [src]
trace {0|1|2|3} [lin|log|ri|rx|rlc|gb|glc|rpxp|rplc|rxsh|rxser]
trace {0|1|2|3} {scale|refpos} {value}
For this exercise, I used Teraterm5 which allows setting delays after each character and after each line so that the NanoVNA is not overrun.
Above, the Teraterm serial port setup.
The commands to perform the setup follow, they can be pasted into teraterm in one go,
trace 0 swr s11 trace 0 scale 0.2 trace 0 refpos 0 trace 1 smith s11 trace 1 rx trace 1 scale 1 trace 1 refpos 0 trace 2 r s11 trace 2 scale 20 trace 2 refpos 0 trace 3 x s11 trace 3 scale 20 trace 3 refpos 4 trace
Here is capture of the console session.
NanoVNA Shell ch> trace 0 swr s11 ch> trace 0 scale 0.2 ch> trace 0 refpos 0 ch> trace 1 smith s11 ch> trace 1 rx ch> trace 1 scale 1 ch> trace 1 refpos 0 ch> trace 2 r s11 ch> trace 2 scale 20 ch> trace 2 refpos 0 ch> trace 3 x s11 ch> trace 3 scale 20 ch> trace 3 refpos 4 ch> trace 0 SWR S11 0.200000000 0.000000000 1 SMITH S11 1.000000000 0.000000000 2 R S11 20.000000000 0.000000000 3 X S11 20.000000000 4.000000000 ch>
In this firmware, display settings are saved as part of the calibration data, so if the instrument is setup full (incl calibration) when you run the above script, you could save it to slot 6 with the “save 6” command.
The original / default trace setup follows.
ch> trace 0 LOGMAG S11 10.000000000 7.000000000 1 LOGMAG S21 10.000000000 7.000000000 2 SMITH S11 1.000000000 0.000000000 3 PHASE S21 90.000000000 4.000000000
This may or may not work on other versions of hardware and firmware, try it entirely at your own risk.