The R-390A/URR is considered the finest HF Receiver ever built. This receiver was designed in the early 1950’s and released in February, 1954. The R-390A can receive signals down to its -143db noise floor.
Originally built by Collins Radio Company, the R-390A was designed by two teams. The mechanical team led by Fred Johnson and the electronics team led by Ernie Pappenfus. Besides Collins Radio, there were 13 other sub-contractors who built the R-390 until 1984.
These receivers were used in all branches of the military, CIA and NSA for monitoring communications from behind the Iron Curtain during the Cold War years. This receiver was classified as “Top Secret” until the mid-1960’s and remains in use today by the NSA.
