This is the Realistic TRC-48, Radio Shack's deluxe 23 channel mobile/base AM/SSB radio. It featured Volume, Squelch, R.F. Gain, S/R.F. meter, and a transmit/receive synchronized Clarifier.  Other controls included; switches for P.A. and Noise Blanker, a remote volume control on the stock microphone, as well as a built-in A.C. power supply. This radio was available starting from late 1975, when it replaced the almost identical TRC-46, to 1977, when the new 40 channel models would replace it. This radio was a fairly decent performer,  Receiver performance was about average with respect to both sensitivity and selectivity. When used in a densely populated area, with many people on different channels, it got a bit rough, although not too many other radios of the time period could fare much better under those conditions. Transmitter performance was average as well. SSB power could reach about 15 watts, and AM modulation was strong and sounded good on a D-104 mike.  Common modifications for this radio included channel expansions with added crystals, and expanding clarifier range. The clarifier control was of the variable capacitor type, and expanding its range was accomplished by placing an inductor in series with it.  One personal negative for me, was how this radio was packaged. Was it primarily a mobile, or a base station? This radio was designed to handle both jobs, but as a mobile it was a bit bulky and heavy, and as a base station, it lacked such niceties as  a larger internal speaker, and a large S/R.F. meter with SWR measuring capability. Such is the nature of compromise.  Neither side is represented to its fullest potential, and the final product ends up to be less than the sum of all its parts. This radio was nonetheless popular with a few locals, including Steve, Circuit Breaker, and Piero.