This is Radio Shack's Realistic TRC-451, deluxe AM/SSB mobile radio, circa 1981. Cosmetically, it is identical to the earlier, 1980 vintage TRC-450. However, it uses a much less frequency modification-friendly chassis. Instead of the 450's Uniden MB-8719 PLL chassis, it uses the upD2824 PLL chassis, identical to the Cobra 146. User features include the standard fare of Volume, Squelch, R.F. Gain (with NB selection), a receive-only Clarifier, a Mode selection with indicators, and a display DIMmer control. Also included are a PA/Monitor function, and internal/external speaker selector switches, as well as an S/R.F. Meter, and a modulation indicator.
Receiver performance is exceptional, with both good sensitivity, decent selectivity, and a low noise floor. For those who pay attention to signals, the "S" meter is responsive and easy to read, but in typical Uniden fashion, is overly sensitive at the low end, while compressing at the high end. Both AM and SSB transmit audio quality are excellent. Power output on SSB will easily hit 20 watts, and AM modulation is good up to about 5 watts of carrier. PLL frequency mods are not nearly as rewarding as they were with earlier PLL devices. The upD2824 is a "ROM coded" 40 channel only PLL, which cannot be modified for extra frequencies. Far more "exotic" methods need to be employed if you are determined to put this radio where it isn't supposed to be. The fact that this radio isn't easy to mod for additional frequencies was of no concern to me however, as I wanted it to remain basically stock, although I did unlock the clarifier control as I can't stand the fixed transmit/receive only stock clarifier setups on SSB.
This radio was obtained as the product of another horse trade, and, for a time, saw daily use as the local area activity monitor and source for the Streaming audio server. It was also my "Daily Driver" radio for a goodwhile. On a scale of 1 to 10, I give it about a 6.5, as it is really a good performing radio, even though it's not to best choice for someone looking for a radio with a lot of frequency capability.