A rotatable antenna apparatus is provided that has both a fixed unit for attachment of the apparatus to an external structure, and a rotatable unit mounted on the fixed unit and comprising an antennaassembly and processing circuitry coupled to the antenna assembly for performing signal processing operations. An interface unit is coupled to both the fixed unit and the rotatable unit, and is used to route a cable to provide a wired connection from the fixed unit to the processing circuitry. The interface unit includes a cable housing within which a length of the cable is enclosed in a coiled arrangement. A control mechanism that is coupled to the interface unit is then arranged to constrain the amount to which the length of cable is wound and unwound within the cable housing so as to inhibit application of a stretching stress on the cable during rotation of the rotatable unit. This provides a very efficient and cost effective mechanism for providing a wired connection to the processingcircuitry included within the rotatable unit.