We found this circuit in the La Radio per Tutti magazine in Italy in 1926. The coil can be made with 100 coils 28 thread in a cardboard or PVC tube of 2 to 2.5 cm and with 10 in 10 or 15 in 15 turns. The antenna must be long, and the galena crystal can be replaced with a germanium diode. The handset must be of high impedance.
