Note
QST, Feb 1971, p. 107.
QST, Feb 1975, p. 109.
QST, Jun 1976, p. 129.
QST, Apr 1977, p. 123.
The 510X 10-channel, crystal-controlled oscillator plugged directly into the 250, 270, and 500 series transceivers as well as the 600 transmitter and receiver. It was designed for use on the 80–15 meter bands. A front panel switch selected from among 10 crystals, and a vernier control knob netted the crystal on the exact frequency.