A megahertz is one million (or 106) hertz.
See hertz, kilohertz (one thousand hertz), gigahertz[?] (109 hertz), terahertz[?] (1012 hertz), and petahertz[?] (1015 hertz).
... (SOE) begun to help and supply the resistance from November 1940. Head of the French section was colonel Maurice Buckmaster[?]. They sent weapons, radios and radiomen and ...