This circuit, from an old American publication, retransmits the sound of sound equipment, from a tape player or CD player and MP3 to an AM radio a few meters away. The circuit can use a BD135 and be powered by voltages from 6 to 12 V. The modulator transformer can be output from transistor radios and the coil has 50 + 50 turns of wire 28 in a ferrite rod. The antenna must be 1 to 5 meters long. Adjust the volume of the sound to have a sound without distortion in the transmission.
