In the presented receiver, from a 1964 documentation, a transistor is used as a detector, operating without power. The antenna must be very long and L1 formed by 100 turns of wire 28 in a ferrite rod. L2 is formed by 30 turns of the same wire over L1. The handset is high impedance. Any transistor can be used, but better results are obtained with older types of germanium.
