This circuit can function either as a crystal or galena receiver with a pre-amplifier using a FET and exciting a high impedance or piezoelectric headset, as well as being connected to the input of an amplifier, to function as an AM tuner. The FET can be MPF102 or BF245 and the coil consists of 100 turns of enameled wire 28 or 30 on a broom handle or 1inch PVC pipe 20 cm long. The wire is scraped to run a cursor where the antenna is connected. The variable is obtained from an old tube radio. The power comes from a 9 V battery.
