Fifty years ago this month, the July 1968 issue of British magazine Practical Wireless showed this simple two-transistor medium wave receiver. The circuit employed two transistors, a BC-108 NPN transistor, and an OC-171 PNP.  The actual transistors don’t appear to be critical, but one must be PNP and the other NPN.

The interesting twist of this circuit is that it keeps working when turned off, since the junction of the second transistor functions as a diode, turning the radio into a crystal set.  The addition of power makes the signal considerably stronger.