Pattern for Conquest by George O. Smith

The scene at the proving grounds was a bustle of activity. In the center of the area stood a huge machine with a paraboloid reflector, pointing skyward on gimbals. Supporting the projector was a girdered and trussed platform, with tractor beams on each corner, pointing down to the center of Terra. Vast was the machine; no telescope in the Solar Combine was half as solid as the trunnions and bars that rigidized the setting of the relatively small, ten-foot bowl of the projector.

A line of portable telephone poles, strung with portable wiring, led from the housing below the projector. Off across the proving ground they went to a master-control office almost lost in the horizon and the haze.