The Antenna Analyzer made by EU1KY was further developed by Ian, KD8CEC, it used a similar calibration solution here. It is important for L / C measurement when you use open, short circuit, and load 50 Ohm calibration elements on millimeter-accurate spikes of the same size. As I have been following and building the EU1KY AA myself, you can read more on my website that interests me.
73, Gyula HA3HZ