Abstract: A drive control apparatus for an electrically-driven type extensible/retractable antenna comprises a control circuit connected to a power supply, a motor controllable by the control circuit to be rotated in a normal or a reverse direction, a multi-threaded type worm provided on an output shaft of the motor, a worm wheel engaging with the worm, a drive gear receiving a rotational force of the worm wheel to allow it to be rotatably driven, a drive rope having a rack in mesh with the drive gear and adapted to be moved in a longitudinal direction upon the rotation of the drive gear, an extensible/retractable antenna element driven by the drive rope to allow it to be extended or retracted, stopper means for mechanically stopping an extending or a retracting motion of the antenna element when the antenna element reaches an extension or a retraction limit, a shock absorber made up principally of an elastic member for alleviating an impact force by which the antenna element is stopped upon collision with the stopper

Abstract: A reflector antenna is constructed for operation in at least two frequency ranges. For this purpose the concave surface of the antenna reflector body, which preferably has a paraboloid configuration, is provided with surface zones arranged in regular arrays or patterns. These surface zones provide antenna or reflector elements which are reflecting or transparent with regard to a particular frequency range or band width, while other surface zones of the antenna reflector surface are transparent or reflecting in another given frequency range or band widths. Thus, depending on the configurations and dimensions of these different surface zones one and the same antenna is capable of handling frequencies in a plurality of different band widths and different apertures.