Note
CQ, Nov 1967, p. 73.
QST, Dec 1967, p. 178.
QST, Feb 1968, p. 1.
QST, Nov 1968, inside front cover.
QST, Jan 1969, p. 152.
QST, Apr 1971, p. 1. (SR-400A)
QST, Jan 1972, p. 1.
QST, Apr 1974, inside front cover.
QST, Jul 1974, p. 161. (on sale)
True dual receive when used with the HA-20.
Originally announced as the SR-540 (QST, May 1966, p. 1) in a preview ad saying "Watch for it next month." But the unit didn't actually appear until November 1976, about 18 months later, as the SR-400.
The SR-400A “Cyclone III” transceiver offered improvements over the SR-400 in the form of increased power and a factory-installed cooling fan. Input power to the 6DK6 finals was 550 watts on SSB and 350 watts on CW. The transceiver covered 80–10 meters and required an external power supply, PS-500A.
References
Review (SR-400): QST. Oct 1968, p. 49.
Brief description. Electronics World, Sep 1969, p. 80.
