Improvements in Piloting Cable Receiving Apparatus

The further development of an aural receiver for the piloting cable system of guiding ships into harbors is described. In particular, the choice of a detecting coil of the most desirable number of turns, the proper choice of transformer input impedance and step-up ratio, and the use of audio frequency tuning of the coil circuit are discussed. The design of the latest coil, receiver, and amplifier is given.