This young woman is now about 90 years old, but in the September 1938 issue of Popular Mechanics, she is shown helping her father pull in a shortwave signal with the simple one-tube receiver described in that issue. It uses an RK-43 dual triode tube as regenerative detector and audio amplifier.

The set can be initially constructed for the standard broadcast band.  Then, to pull in the shortwaves, a fixed capacitor is switched in series with the main tuning capacitor to lower its capacitance.  In addition, shortwave coils are used in place of the coil for the broadcast band.