Abstract: The antenna mast or tower structure includes a base adapted for attachment to a van, preferably a van equipped with suitable mounting jacks designed to support the base. Both the base and the plurality of telescopically nested tubular subassemblies are adapted to be extended by cables, each cable being secured at one end to a lower end of the subassembly to be raised, and at its other end to a motorized cable and pulley system that includes a driven drum, plurality of fixed pulley blocks mounted to each subassembly near the upper end thereof, and a movable pulley block arranged to achieve a mechanical advantage in the cable and pulley system itself.