The ARPA Lincoln C-Band Observables Radar (ALCOR) was developed and built at Roi-Namur in the Reagan Test Site between 1968 and 1970.

ALCOR is a high-power, narrow-beam coherent, chirped monopulse tracking radar. ALCOR supports two operating modes, narrowband (6 MHz bandwidth) and wideband (512 MHz bandwidth). The wideband waveform provides a range resolution of approximately 0.5 meters. A doublet waveform, consisting of two closely spaces wideband pulses, allows measurement of target velocity.

ALCOR also has a C-band beacon tracking subsystem that is used to acquire beacon equipped targets at long ranges. The beacon subsystem has provision for storing four independent sets of beacon parameters, allowing the radar to switch tracks between beacon bearing vehicles in seconds. Objects under beacon track can be switched directly to skin mode when Signal-to-Noise ratio is adequate. The radar is capable of simultaneous range and angle track on two targets in beacon or skin mode.

ALCOR also serves as a primary weather measurement radar for Reagan Test Site.  Radar Cross Section data recorded following mission activities can be converted to cloud moisture content, thus providing a measure of the weather severity encountered by a reentry vehicle. A weather analysis mode provides Plan Position Indicator (PPI) and Range-Height Intensity (RHI) type presentation of radar cross-section returns from moisture concentrations in the atmosphere.