Note
QST, Jun 1978, p. 89.
QST, Apr 1980, p. 52.
The Model 277 matching antenna tuner for the Century 21 transceiver had a built-in SWR bridge and meter. It handled up to 200 watts, covered 1.8–30 MHz, and included a balun.
References
Review. QST, Apr 1980, p. 52.