If you had put together this minimalist little shortwave set when it was published in Popular Science in August 1939, you would have been able to use it to pull in the news of the beginning of World War II the next month.

The little set is simplicity itself. It uses a single 1E7G tube, a dual pentode.  Half is used as regenerative detector, with the other half serving as audio amplifier.  There are only three controls on the front panel:  The tuning dial, regeneration control (with on-off switch built in) and another potentiometer for adjusting filament voltage.  The voltage was a compromise, since the RF section needed slightly less voltage than the audio amplifier, but there was still plenty of volume left to drive the headphones and pull in the war news.