Telescoping antenna movable by means of a d.c. motor

An antenna control system for extending and retracting a telescoping antenna for a vehicle comprising:

• a d.c. motor, having first and second terminals, coupled to said antenna, said motor rotating in one direction when a voltage having one polarity is applied across its terminals thereby extending said antenna and in the reverse direction when a voltage of the opposite polarity is applied across its terminals thereby retracting said antenna;
• a control device comprising,
• a polarity responsive timer for closing a contact for a predetermined interval when the polarity of the voltage applied across said timer is reversed, and,
• a polarity reversal switch for coupling a d.c. voltage source across the terminals of said polarity responsive timer with a selected polarity, the polarity of the voltage across said timer being determined by the position of said polarity reversal switch;
• and,
• a switching device having first and second states, said switching device in its first state coupling said polarity reversal switch through said contact to said d.c. motor to cause said motor to rotate in a direction determined by the position of said polarity reversal switch for an interval of time determined by said timer, said switching device in its second state coupling a d.c. voltage source of selectable polarity across said motor for rotation thereof in a direction determined by the polarity of said applied d.c. voltage source.