Abstract: A rotatable reflector antenna system that supports on-the-move communications to and from a mobile land, airborne, or maritime vehicle with a remote communication device, such as a geostationary satellite. The antenna system can include a pillbox antenna, a line feed antenna, or an array of horn antennas that convey electromagnetic waves between a transceiver (transmitter and/or receiver) and a reflector. The reflector may be embodied as a singly curved, parabolic cylinder reflector coupled to support members in a manner that enables the reflector to rotate with respect to the antenna. The reflector can rotate in a first direction, such as an elevation rotation, and the entire antenna system including the reflector can be mounted to a turntable or other rotatable platform that rotates in a second direction, such as an azimuth rotation.