Note
QST, Aug 1977, p. 138.
QST, Apr 1980, p. 176.
QST, Apr 1981, p. 100.
The Century 21 solid-state transceiver ran 70 watts CW input on 80-10 meters. Coverage on 10 meters was the lower 1 MHz of the band. It featured full OSK and a three-position audio filter. The receiver was a double direct conversion design. The 120 VAC power supply was built-in.
The 574 is the same as 570 but with digital display.
References
Review. Popular Electronics, Feb 1978, p. 85.