A 16,000-mc scanner is described which scans a40degazimuth sector alternately with each of two beams at a rate of 17 scans per beam per second. The beams have half-power vertical and horizontal beamwidths of0.76degand1.06degrespectively and are separated vertically by an angle of1.85deg. Horizontal collimation of each beam is achieved by a geodesic analog of the two-dimensional Luneberg lens. The lenses feed a section of a semiparabolic cylinder for effecting vertical collimation. Feeding the lenses is a switching system, consisting of two four-way turnstile waveguide switches and a waveguide chopper switch, which gives a scan-time dead-time ratio of 8:1.