On Mon, May 30, 2022 at 12:50 AM, tuckvk3cca wrote:
Thanks, just been reading the late G3TXQ articles. Very useful. He said a one
port measurement is no good. Surely if I terminate the choke with a r ohm
resistor , I can measure R + j X that way and subtract to get (R - r) + j X.
Has anybody tried that?
One port S11 measurement on a NanoVNA-H4 gives good results up to several thousand ohms (see attached 3K ohm example). It is better than using the S21 serial method. The S21 serial method does not work that well on a NanoVNA. The reason is that the Ch0 and CH1 impedances are not 50 ohms across a wide range of frequencies and the NanoVNA does not do a 12 point calibration. There have been several discussions in this group about measuring chokes, baluns and impedance using various methods. Lots of good info if you do a group search.
Roger
Roger Need
