Comment left 2020 May 29 on YouTube video in the title. This video covers MOSFET, dual gate MOSFET, JFET and BJT tuned preamps (preselectors) for his shortwave crystal radio.
“The talk about using 18 volts for the cascode got me thinking about tube designs. When the plates need 100+V, and when the heater to cathode voltage is rated 100V max, it would be best to use a circuit that is cascode to the RF only, not the DC. One could do the same with the three 2N2222’s too. The compliance would be better and the 9 volts would be more than adequate.”
I especially like the variable couplers and faraday shield between the coils. They require a lot of custom mechanical work but they do a lot for improving the performance.