Hi, Rune!
Thanks for your answer in NanoVNA-Saver0.2.0 thread.
I will continue here.
There was a task to find out an impedance of unknown teflon coax cable, which looks like 75 Ohm.
I did it with the help of NanoVNA TDR measurements. A 500 mm piece of 50 Ohm teflon coax cable with SMA connector was plugged into the device and a piece of unknown cable was soldered to its other end and left open. The results are on the device screen photo.
Then I decided to do the same with the help of the built in TDR function of NanoVNA-Saver, as you suggested.
What I saw in TDR window, looks correctly, but when I put marker on the curve, only distance was displayed, but not an impedance value. See the next screenshort. The impedance value can only be read approximately from the impedance axis. I think that it would be very useful to display an impedance under marker.
After that I put device in TDR mode again, menu item - TRANSFORM/LOW PASS STEP and run Sweep in NanoVNA-Saver. The results were very interesting. TDR window displays something wrong. But ¡°S11R+jX¡± window seems to be alike device screen. See the next screenshort. The markers shows true values of impedance of two pieces of cables. Only horizontal axis is in MHz. :)
I think, that it is one of the ways to measure transmission line impedance with NanoVNA-Saver.
Thank you very much!
Merry Christmas!
73! Andy, UA3RAW
Andy UA3RAW
