Abstract: A control circuit utilizing: a counter which provides first and second output signals at spaced apart time intervals and delay means for stopping and starting the counter; and switch means having start and stop inputs and an output connected to the delay means of the counter. The switch means, being arranged to start the counter when the start input is energized, and being arranged to stop the counter when the stop input is energized. The stop input of the switch means being actuated by the first counter output signal.

Abstract: A homing system utilizing a loop antenna positioned at approximately 45.degree. to the vertical to provide an electromagnetic field having both horizontal and vertical components. These signal components are picked up by a vertical loop stick antenna alternately connected to one of two bifilar wound coils of a horizontal loop stick antenna to provide alternating signals. The strength diagrams for the alternating signals are cardioid shaped and are arranged back to back with their null point passing through the intersections of the back to back signals. The null point of both antenna systems occurs when the horizontal loopstick antennas are at right angles to the electromagnetic lines of force; and any time that the horizontal loop sticks are turned at an angle relative to their null point, a difference in signal strength exists between the two antenna systems. This is picked up, and is amplified at separate time intervals by a common amplifier.