To wit, we present this compact two-tube “spy radio” transmitter. From the look around ... the only real nod to modernity in the build is the use of 3D printed forms for the coils.

[Pete Juliano, N6QW] built a 20 M QRP CW transmitter using just a handful of parts. That in itself will not raise any eyebrows, until you find that he built it using one of the very first RF ...