This circuit from a 1940s publication transmits the signals from a mono record player of the time to a nearby medium wave radio. The antenna is a piece of wire from 1 to 3 meters and the range can reach a few tens of meters. The oscillating coil has a primary of 100 turns and a secondary of 10 turns in a cardboard or PVC tube with a diameter of 1.5 to 2 cm. The circuit is powered directly from the mains without the need for a transformer.
