https://www.rfcafe.com/references/short-wave-craft/microhenrys-coil-december-1931-january-1932-short-wave-craft.htm
How Many Microhenrys in That Coil?, December 1931/January 1932 Short Wave Craft - RF Cafe
Handy nomograph, chart, and a table of typical values. Nagaoka coefficient
short wave crafthow manycoildecemberjanuary