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FUNCTION: Performs measurements and calibration of antennas for satellites and aircraft or groundbased systems. The chamber is primarily used for optimizing antenna designs, configurations, and performance on satellites and ground planes. It produces 2D and 3D antenna patterns and swept voltage standing wave ratio (VSWR) measurements in both hardcopy and softcopy format. An associated program called STK (Satellite Tool Kit) can also be used to analyze the data in a simulated environment, using the measured antenna patterns. DESCRIPTION: The Precision Radio Frequency Anechoic Chamber is a tapered structure 44 ft long × 14 ft high × 16 ft wide, with a spherical quiet zone 5 ft in diameter. The quiet zone is specified to be isolated from the ambient RF environment outside by 150 dB. The chamber meets the performance specification requirements of free-space voltage standing wave ratio, axial ratio, and reflectivity over the frequency range of 220 MHz to 40 GHz. Reflectivity levels inside the chamber are less than 50 dB from 1 to 40 GHz. The chamber is instrumented for automated measurement capability. The chamber is inside a specially constructed electromagnetic interference facility shielded with 1/8-in.-thick steel plate on all walls, floor, and ceiling. This provides 100 dB attenuation to RF signals from 50 MHz to 100 GHz. INSTRUMENTATION: Antennas under test receive signals transmitted from the opposite end of the chamber by octave-band source antennas. Synthesizers and amplifiers feed the source antennas. Received signals are routed to an HP8510C network analyzer, where they are processed and sent to the control computer. The Flam and Russell 959 Automated Antenna Measurement System is used to control the HP8510C and the positioners and to perform the analysis and plotting.