The Green Bank 6-cm Radio Source Catalog (GB6) is an Astronomical Catalog from an Radio Astronomical Survey of the northern hemisphere conducted in 1986-1987 by the Green Bank 300ft Telescope (GB300) at Green Bank Observatory, using the NRAO Seven-Beam Receiver. Many Radio Galaxies were discovered and still are known by their "GB6" designation.
The Parkes-MIT-NRAO Surveys is the southern hemisphere analog.
Green Bank 300ft Telescope (GB300)
Parkes-MIT-NRAO Surveys (PMN)