Eighty-five years ago this month, this gentleman was practicing his Morse code with this one-tube code practice oscillator as described in the December 1935 issue of Popular Mechanics.

The set used a 12A7 tube, half of which was used to rectify the household current, with the other half serving as oscillator.  A “curtain burner” line cord was used to step down the voltage to light the filament.

The article suggested working in teams to master the code, and pointed out that it was a good idea to start with an experienced operator who could demonstrate the proper formation of the letters.