This two-tube circuit with a 1V wire transmits signals to a nearby medium-wave radio. The circuit is from a 1945 documentation and has, in addition to the filament cell, a 22.5 V battery.

This two-tube circuit with a 1V wire transmits signals to a nearby medium-wave radio. The circuit is from a 1945 documentation and has, in addition to the filament cell, a 22.5 V battery.