Telephone remote control circuit for an antenna test site

A circuit is described which permits the remote control of several quantities, such as transmitter frequency, direction of polarization and RF match, at an unattended antenna tower. It requires only a single telephone line, which already exists for communication purposes at many test sites. Each quantity is controlled by a separate motor. The motors are controlled separately from the control end. This is achieved by adapting and installing a dialing circuit which allows, first, any desired motor to be "dialed"; next, to be controlled; and, finally, the line cleared so that another motor can be called. The parts for the dialing circuit were purchased at a total cost of about $150. Detailed circuit diagrams are given showing how the circuit is constructed.