The radio built entirely out of 2N3904 transistors (and a varactor for tuning capacitance) works as expected. We covered [QRP Gaijin’s] diary when he was building an early version of this radio.

Fortunately they’re a very simple circuit with only one 2N3904 transistor, but the snag is they need a high voltage power supply well over 100 V. So the challenge isn’t making the pulse ...