The R-388/URR is the US military designation for the Collins 51J-3 general-coverage receiver. It tunes 0.5 to 30.5 MHz in thirty 1 MHz bands, using a crystal-controlled first conversion and a permeability-tuned oscillator (PTO) that gives the same linear dial calibration on every band.
R-388 articles on this site
- Crystal Filters & Mechanical Filters — A-Line Receivers, KWS-1, R-388, R-390 & R-390A Collins – IF Selectivity Filter Master Reference
- Web-888 with the Collins R-388/URR PTO Precision, SSB Capability, and Thirty-Band SWL Coverage — Architecture, Integration, and Eight Operating Procedures
- R-388/URR Failure Prevention Kit — Component & Modification Design
- Collins R-388 Receiver Cabinet Restoration
Related receivers: R-389/URR · R-390/URR · R-390A/URR · R-391/URR · R-392/URR
Mike Peace VK6ADA / r-390a.net and foxtango.org Administrator