This is Royce's model 640 deluxe SSB base. This radio had more knobs, buttons, and meters, than most people knew what to do with. Besides the usual standard features of Volume, Squelch, the standard 23 channels, and a synchronized Transmit/Receive Clarifier, it also sported a clock with alarm function, an R.F. Gain, Tone control, PA volume (on a base station?) SWR metering, with separate calibration and reflected SWR meters, noise blanker and a switchable AGC (why?). The radio was an overall good performer, which mated up well with either Turner or Astatic mikes. Receiver performance was impressive as well, with a better than .3 uV sensitivity. One had to be careful though as you could slam the "S" meter if you turned off the AGC when a strong neighbor keyed up. It was also a good looking radio to boot, reflecting the greater attention paid to ergonomics and style which found its way into the 1970's era radios. At least 4 people; Channel Master, Blue Cougar, Pheasant and Red Dog ran 640's in our area. I became the proud owner of one in the early part of 2006, to add to my growing retro collection. It holds it's own against the newer radios, although I did find the squelch action lacking in hysterisis, and it would close with an objectionable "thunk". Other than that small objection, it is a good performer, the "S" meter is fairly linear, and the transmit audio has a pleasing fidelity. Power output was around 5 watts on AM, and around 15 on SSB. Better audio performance on AM was gained when the power was backed down to around 3 watts. On a scale of 1 to 10, I'd rate the Royce at a 6.
Copied from CB Museum site...did not find much else...but do remember replacing crystals and finals in a few back in the late 70's
All the Best
BJ