Something that might be of interest is that the Surrey Amateur Radio Club, VE7SAR, < <>ve7sar.net > has a wonderful newsletter that comes out bi-monthly. The newsletter is usually around 110 pages. The last several issues have had articles titled, Measurements with the NanoVNA". The Nov - Dec 2020 article deals specifically with "Establishing the Characteristics of Unknown Toroids".
73,
Gary - W6GVS
Dowagiac, MI
