Note
QST, Jul 1952, p. 95.
QST, Jun 1953, p. 101. {"prices slashed")
See QST, Jan 1952, p. 56, for a discussion of Rothman modulation.
Also, an ad for Terminal Radio Corp featured a series of Rothamn devices in QST, Mar 1952, p. 109. These may be the same devices marketed by Marmax that first appeared in the July 1952 issue.