urn:nasa:pds:context:instrument:gbo.gbt_100m.4mm_receiver 1.0 1.16.0.0 Product_Context 2021-04-09 1.0 Initial version. urn:nasa:pds:context:facility:observatory.gbo instrument_to_facility urn:nasa:pds:context:telescope:gbo.gbt_100m instrument_to_telescope Green Bank Telescope 4mm Receiver Radio Receiver 4mm dual-beam receiver to cover the low-frequency end of the 3mm atmospheric window from 67-93 GHz.