[RadioShack] TRC-458 and TRC-490 differences - was there an F.C.C. mandate, or did they change as normal evolution?

[Sean Kelly]

Hi All,

The specifications for the two S.S.B. C.B. radios in the subject header are mostly similar. The TRC-458 is in the 1979 catalog and the TRC-490 is in the 1980 catalog. The major differences shown in the specifications are that the TRC-490 uses less power, has greater image rejection, and lower spurious emissions [1]. What I'm wondering is if there was a change in the F.C.C. rules in 1979 that mandated the lower spurious emissions from C.B. transmitters, or if Tandy just decided to try to make the TRC-458 better.

The 1978 catalog said that the TRC-457 and TRC-458 were new for '78, and the TRC-457 was replaced by the digital TRC-459 in 1979. Those are short lifespans for the TRC-457 and TRC-458.

Thanks,
Sean

[1] 
TRC-458 AM/SSB CB Transceiver  http://support.radioshack.com/support_electronics/doc46/46643.htm
(210-1581)

TRC-490 AM/SSB CB Transceiver  http://support.radioshack.com/support_electronics/doc46/46650.htm
(210-1583)