Click on picture to expand.

The R390A/URR is without question the best receiver (in my opinion) mass produced. The 26 tube receiver is mechanically complex but designed to military FRM (Field Replaceable Module) specifications. The original design was from Collins Radio. Later the government contracted with a number of manufactures to manufacture this unit. Some of the later units had updates that have made them technically more desirable. Obviously Collins collectors collect the Collins manufactured units. In many cases a unit will have a Collins label but have modules manufactured by others.

The unit shown above is a "CIA" (black paint) unit restored by Rick Mish. His restoration work is well known and immaculate. The restoration work done by Rick Mish is the highest quality I have seen. If you can imagine disassembling this receiver down to the individual components cleaning and reassembling it back to original, burning it in for weeks then performing several factory alignments (over another week) that produce specifications better than factory. Every resistor and capacitor in the unit is measured and brought to factory specification. I have compared this receiver to the modern Yaseu 1000D and ICOM 781 in a live application and have found this R390A to be superior. We all know that hearing, in reality, is not reflected in the lab specification results. Hearing has to do with the interface between the device and the brain's ability to discern intelligence. The CV-591/URR added as a product detector (SSB Capability) to the R-390A/URR receivers.

The picture to the right is a typical Military application for diversity operation of the R390A/URR. Diversity is a application where at least two receivers are connected to two separate antenna spaced a half wave apart (called - Space Diversity). This operation minimizes the receiver fading effect.

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