Abstract: A broadband partial fan cone direction finding antenna and array disclosed. The antenna includes a radiator having a partial cone shape. The radiator substantially occupies a spatial area defined by a portion of a cone and the cone is defined by a cone axis, a cone height, and a cone angle. The cone has a base and an apex, and the portion of the cone is defined by a cone sweep angle. The cone sweep angle is determined as the angle subtended by a projection of the portion of the cone projected onto a plane that is perpendicular to the cone axis. The cone sweep angle is less than 360° so that the portion of the cone is bounded on its sides by edges which extend radially from the apex of the cone outward to the base of the cone.

Abstract: A slot antenna is described. The slot antenna includes waveguide having a first side, a second side, a third side, and a fourth side, a closed end and an open end. The second side extends substantially perpendicularly from a first end of the first side. The third side extends substantially perpendicularly from a second end of the first side. The fourth side extends between the second side and the third side with the fourth side substantially parallel to the first side. The sides and the closed end form a cavity. A feeding point is located substantially midway between the first end of the first side and the second end of the first side. A T-Bar is located inside the cavity, the T-bar having a center member extending from the feeding point into the cavity and a cross member having a length extending across the cavity between the second side and the third side.

Abstract: A system and method are disclosed for providing a real-time map of ionospheric properties. An ionospheric model is provided that provides a baseline description of ionospheric properties. A primary data source is provided that is indicative of real time propagation data obtained for the ionosphere in the vicinity of a control point. The real time propagation data is indicative of the critical frequency for the ionospheric layer. The ionospheric model is modified based on the real time propagation data obtained for the ionosphere in the vicinity of the control point. This includes modifying the critical frequency for the ionospheric layer. In this manner, the ionospheric model is updated according to real time propagation data.

Abstract: A door latch includes an elongated stationary case and a latch bolt mounted to reciprocate longtudinally in the case between outwardly extended and inwardly retracted positions. The latch bolt is driven between the two positions by a driver mechanically connected to the latch bolt and longitudinally movable within the case under control of first and second cams. The rotation of either cam will cause the driver to move against the force of a helical spring in direction to pull the latch bolt to an inwardly retracted position. A pushbutton key is mounted to a sidewall of the case and movable in direction into and out of the case to lock one of the cams against rotation. A pin, integral with and extending radially from said key, is received by a camming means on the other cam whereby rotation of the other cam will move the pin in direction to retract the key from the first mentioned cam. A detent in the case is held in position by the helical spring to frictionally engage the outer surface of the key.