Four Frequency Cassegrain Receiver and Feed Assembly, June 1974

In June 1974, John Payne (back to camera), Mike Balister, and Ken Kellermann consider the four frequency Cassegrain receiver and feed assembly, with optics designed by Peter Napier, that was the prototype system for the VLA and was also used for the VLBA. It was a new and innovative concept, first developed by the Jet Propulsion Laboratory for use on their Deep Space Network antennas, where the four feeds were offset from the electrical axis and could be illuminated by rotating the asymmetric subreflector. Here it is being installed for testing on the 140ft antenna in Green Bank. Mike says, "Judging by the way I was clutching my head [Ken] must have been giving us a hard time." Ken says he was the project scientist "assigned to hassle the Electronics Division." He adds, "Note I was comfortably sitting down and seem to be the only one that didn’t look puzzled, as appropriate for an advisor." After installation of the Cassegrain cabin on the 140 ft telescope the system was integrated and evaluated by Chuck Brockaway and Tom Dunbrack.

Records of the NRAO

NRAO/AUI/NSF

Still Image

GB74-11521-JohnPayne-MikeBalister-KenKellermann-June1974.jpg

Slide

1974-06

NRAO/AUI/NSF

GB74-11521

Photographs Series

140 Foot Telescope Unit