Note
QST, May 1965, p. 125.
QST, Dec 1965, p. 127.
QST, Oct 1966, p. 129.
QST, Feb 1967, p. 125.
QST, Jan 1968, p. 115. (405X)
CQ, Jan 1969, p. 6. (510X)
QST, Dec 1969, p. 116.
QST, Oct 1972, p. 145. (510X)
QST, Jul 1973, p. 146.
QST, Aug 1974, p. 111.
QST, Jan 1975, p. 109.
Swan call this a "MARS Oscillator," presumably because you could use it to switch to MARS frequencies.
The 405(X) gave the operator a choice of five crystal-controlled frequencies in the following ranges: 3–4.6, 6.8–8, and 13.5–15 MHz. A vernier control adjusted the crystal frequency. The 405(X) plugged into the Swan 350 and 400 transceiver. The only difference with the "X" version appears to be the color of the front panel.
The 510X does the same thing, but provides for 10 crystals.
For use with the Swan 400 or 500C.
