Note
CQ, Jun 1964, p. 9.
QST, Jan 1965, p. 99.
QST, Feb 1965, p. 133. (full specs)
R-4A
QST, Dec 1965, p. 139.
R-4B
QST, Dec 1967, p. 127.
R-4C
QST, Mar 1973, p. 119.
QST, Apr 1975, p. 97.
QST, Apr 1976, p. 103. (extra space for WARC bands)
QST, Dec 1977, p. 152.
References
Brief description (R-4B). Popular Electronics, Oct 1968, p. 54.