Note
QST, Dec 1956, p. 172.
CQ, Mar 1957, p. 110 (XC-51)
QST, Oct 1957, p. 177.
The XC-50 crystal-controlled converter covered six meters and had its IF output at 14-18 MHz. Tapetone's XC-144 covered two meters. The XC-144 two meter converter had a 2.8 dB noise figure.Its IF output was 14-18 MHz.
References
Review: QST, Jul 1957, p. 42.
Review: CQ, Dec 1956, p. 45.