1928 Shortwave Converter
This converter was built from plans in an April, 1928 issue of Popular Radio and Television. It is designed to receive short wavelengths used for television broadcasting. The converter has a 4 pin plug which is inserted into the detector tube socket of a standard broadcast band radio of that era, and is designed using 1 tube (201-A) in a regenerative type of circuit. The front knob controls tuning (it uses a National Velvet Vernier drum dial, Type F) while the small knob on the side controls regeneration. Here is a 1929 converter and a 1931 converter.
The Aero Coil shortwave coils in the original box which allows tuning from 15 to 130 meters