SCR-300

thumb|right|Motorola SCR-300 circa 1940 The SCR-300, designated AN/VRC-3 under the Joint Electronics Type Designation System, was a portable frequency modulated (FM) radio transceiver used by US Signal Corps in World War II. This backpack-mounted unit was the first radio to be nicknamed a "walkie talkie".

== History == In 1940, Motorola (then the Galvin Manufacturing Company) received a contract from the War Department to develop a portable, battery powered voice radio receiver/transmitter for field use by infantry units. The project engineering team consisted of Daniel E. Noble, who conceived of the design using frequency modulation, Henryk Magnuski who was the principal RF engineer, Marion Bond, Lloyd Morris, and Bill Vogel. The SCR-300 operated in the 40.0 to 48.0 MHz frequency range, and was channelized. Along with other mobile FM tank and artillery radios such as the SCR-508 (20.0 to 27.9 MHz) and the SCR-608 (27.0 to 38.9 MHz), the SCR-300 marked the beginning of the transition of combat-net radio from low-HF (high frequency) AM/CW (amplitude modulated/ continuous wave) to low-VHF (very high frequency) FM.