GBO RF Anechoic Chamber & Antenna Test Range


FLC Region

Security Lab



Jansky Laboratory
155 Observatory Rd
Green Bank

Laboratory Representative




A shielded anechoic chamber measuring 15 by 15 by 37 feet is located in the Jansky Laboratory at Green Bank. This chamber has been outfitted as a far-field antenna range. The anechoic chamber was designed and specifed for the frequency range 10-94 GHz. The absorber in the room is a combination of AEP-6 and AEP-8; this absorber is described in this data sheet. Maximum distance from transmit to receive antennas is 22 feet. Instrumentation for the range allows far-field measurements from 2 to 115 GHz, but the actual range possible depends upon the size of the feed, the dynamic range requirements, and other constraints. Test and source antennas are mounted 7-1/2 feet above the floor of the chamber (along the axis of symmetry of the chamber) to minimize reflections. Orbit/FR's software package (FR-959) allows fully-automated control of the range receiver, and of 5 axies as follows:

  • Antenna Under Test (AUT) Azimuth rotation
  • AUT Y axis translation (toward and away from source antenna)
  • AUT X axis translation (in the horizontal plane and at right angles to the Y translator)
  • AUT Polarization rotation
  • Source Antenna Polarization rotation

From 2 GHz to 50 GHz, measurements are made using the Agilent 85320A-H50 Mixer Module which rides on the antenna side of the polarization positioner. In this configuration, all 5 axies of the range are available to the user. Our equipment does not cover the range from 50 to 60 GHz, as this frequency range is not commonly used in radio astronomy due to oxygen absorbtion. Above 60 GHz extension heads from Oleson Microwave are used. There were bought and are normally used with an Anritzu "Lightning" Network Analyzer and cover the frequency range of 60-95 GHz (WR-12 waveguide) and 75-115 GHz (WR-10 wageguide). Polarization positioners may not be used above 50 GHz as we have no rotary joints for these frequencies. Polarization changes during test must be made manually, using waveguide twists. To use the chamber please contact Carla Beaudet (GB-2126). The anechoic chamber is a dual-use facility, and spends some of its time configured for RFI testing; at least two weeks of advance notice will assist us in planning for your visit.


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