Abstract: An antenna for the short-range reception of an emitted signal comprises at least two independent sectors for the coarse location of an emission-beam source in two predetermined directions. Each sector is constituted by a waveguide having a single open face oriented in the intended direction of surveillance. A microwave diode is placed within each sector at right angles to, and at the geometrical center of, the supporting wall of the waveguide which is associated with the diode. The frequencies detected by the antenna are within the range of 10.sup.9 Hz to 30.times.10.sup.9 Hz.

Abstract: A wind powered, self-steering device for sailboats of the type employing a main steering rudder and auxiliary steering rudder. The wind vane pivots about an axis that is tiltably adjustable with respect to the horizontal so as to adjust the sensitivity thereof in accordance with the type of keel associated with the boat its point of sailing and prevailing wind and sea conditions. The wind vane axis is also rotatably adjustable with respect to the center line of the sailboat to provide course adjustment. When engaged for operation, the wind vane senses the relative shipwind direction and, when a boat is off course, translates the wind forces on the wind vane into corrective movements of the auxiliary rudder to return the sailboat to course.