An antenna assembly (2) for a base station (3) of a radio telecommunications network comprises an antenna (8) attachable to a support structure (such as a mast (I)) so that the antenna (8) is pivotable relative to the structure (1) about a non-horizontal (preferably a vertical) axis. The assembly includes a motor (42) for causing controlled pivotal ball movement of the antenna (8) about said axis so as to adjust the azimuthal angle of the antenna. This enables a degree of remote control for the footprint of the antenna, thus facilitating the setting up possible adjustment of the network.