Note
Based on a construction article in the April 1947 issue of QST (and featured on the cover), by Mack C. Jones, (W1PNX). Jones' company almost immediately began commercial sales of the unit with an ad in QST the following month. The MM-1 was the first commercially available SWR meter. Later licensed to McMurdo Silver which made it's own version, first in July 1947.
QST, Apr 1947, page 15.
QST, May 1947, page 124.
QST, Jul 1947, page 115.
Concord catalog 9-47, p. 135.
