A rotatable antenna apparatus has a fixed unit for attachment of the apparatus to an external structure, and a rotatable unit mounted on the fixed unit and comprising an antenna assembly and processing circuitry coupled to the antenna assembly for signal processing. An interface unit, coupled to both the fixed unit and the rotatable unit, routes 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 coiled length of the cable is enclosed. A control mechanism coupled to the interface unit constrains the amount to which the length of cable is wound and unwound within the cable housing to inhibit application of a stretching stress on the cable during rotatable unit rotation. This provides a very efficient, cost effective mechanism for providing a wired connection to the processing circuitry included within the rotatable unit.