Apollo Command Module Digital Ranging Generator (DRG), measuring 4″ x 8.5″ x 7″, with a part tag on the bottom: "Digital Ranging Generator, NAA S & ID PN ME-478-0082-0002, Contract No. NAS 9-150, Date of Mfr 12-31-68, Collins Radio Co. PN 514-2101-010, Mfd by RCA For the Apollo Spacecraft, Serial No. 071368450009." In very good to fine condition. The DRG was part of the Apollo Very-High-Frequency Ranging System, put in place as a backup for the rendezvous radar; the system adapted VHF voice radios to perform the ranging function, saving the eighty-pound weight of a redundant radar unit.
Terms and abbreviations used in our descriptions.