VLA Antenna (Mechanical)
The VLA Antenna (Mechanical) These giant antennas, with 25 meter (82 ft.) diameter dishes, were specially designed for the VLA. The aluminum panels of the dish are formed into a parabolic surface accurate to 0.5 millimeter (20 thousandths of an inch). Most of the time the antenna drive system is precisely tracking a radio source across the sky. Occasionally you will see the antenna rapidly slew from one radio source to another. The sounds you hear are the drive motors moving the 100-ton dish, the cryogenic refrigeration compressors, and the air conditioning equipment. Submitted by: Eric Goodill