The R-390A/URR is the redesigned, lower-cost successor to the R-390, introduced in the mid-1950s and built by several contractors. It covers 0.5 to 32 MHz in thirty-two 1 MHz bands, with a mechanical digital frequency readout, and uses Collins mechanical filters for its IF selectivity.
The R-390A Frequently Asked Questions site at r-390a.net holds the wider community reference material.
R-390A articles on this site
- The R-390A Mechanical Filters: Selection, Sources and Testing
- The Collins R-389, R-390 and R-390A
- Choosing an SDR Front-End for the R-390A: A Comparison Matrix
- Solid-State Replacement for the R-390A 26Z5W Rectifier Tubes
- Crystal Filters & Mechanical Filters — A-Line Receivers, KWS-1, R-388, R-390 & R-390A Collins – IF Selectivity Filter Master Reference
- RX-888 Mk II with the Collins R-390A/URR Practical Cascade Integration via the CASCADE-390 IF Tap Kit
- Web-888 Remote Access Setup Step-by-Step Guide for R-390A Owners Joining the Remote Operation Community
- Hermes Lite 2 as R-390A Companion Panadapter Integration Without Modifying the Receiver, and HL2 Transmit for CW, SSB and AM
- Chuck Rippel WA4HHG Practical Restorer, r390a.com Architect, and Keeper of the Bench Standard
- Collins R-390A/URR Audio Output Transformer — Failure, Specification, and Substitution Options
- State of the R-390A Parts Market 2026 – Availability, Critical Scarcities, and Sourcing Strategies for Today’s Restorer
- Dr. Dallas Lankford – His Legacy and Contributions to the Collins R-390A/URR Community
- Collins R-390A/URR Bleeder Resistor Network — Function, Failure, and Correct Replacement
- Collins R-390A/URR Ten Most Common Failures — Ranked by Community Report Frequency
- R-390A/URR: Failure Prevention Kit — Component & Modification Design
- Collins R390A Receiver Restoration Guide
- R-390A Aftermarket SSB Adapters: A Comparison Guide
- R390A Aftermarket SSB Adapters
- TDS – R390A Lubricant
- R-390A Rebuild
Related receivers: R-388/URR · R-389/URR · R-390/URR · R-391/URR · R-392/URR
Mike Peace VK6ADA / r-390a.net and foxtango.org Administrator