SCR-300

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Motorola SCR-300 circa 1940

The SCR-300 was a portable

walkie talkie".[1]

History

In 1940,

VHF FM.[2]

Although a relatively large backpack-carried radio rather than a handheld model, the SCR-300 was described in War Department Technical Manual TM-11-242 as "primarily intended as a walkie-talkie for foot combat troops", and so the term "walkie-talkie" first came into use.[3]

The final acceptance tests took place at Fort Knox, Kentucky in Spring 1942. The performance of the SCR-300 during those tests demonstrated its capacity to communicate through interference and the rugged quality of the design. Motorola was to produce nearly 50,000 of the SCR-300 units during the course of World War II.[4][5]

The SCR-300 saw action in the

Pacific Theater, beginning in New Georgia in August 1943. Colonel Ankenbrandt informed General Meade that "they are exactly what is needed for front line communications in this theater". In his point of view, the main difficulty was keeping them supplied with fresh batteries.[6]

The SCR-300 saw heavy use in the

Normandy invasion and the Italian campaign. It also became "key equipment" that helped deter confusion in the Battle of the Bulge.[7]

The British adopted the design of the SCR-300 for their own use from 1947 as the "Wireless Set No. 31".[8][9]

Specifications

Signal Corps Radio set SCR-300-A

The SCR-300 was an 18-tube battery operated

crystal controlled calibration circuit, easy to use tuning/channel selection, tuning lock to prevent accidental frequency changes, and radio relay or retransmission capability using two SCR-300 units and the appropriate cable assemblies. [8][10]

  • Weight:
With battery BA-70: 38.23 lb (17.34 kg)
With battery BA-80: 32.23 lb (14.62 kg)
  • Power supply requirements:
Filaments: 4.5 volts
Receiver plate: 90 volts
Transmitter plate: 150 volts (using additional 60 volt battery)
  • Antenna:
AN-130-A: Two section flexible whip, 33 inches (84 cm)
AN-131-A: Eight section flexible whip, 10 ft 8 in (325 cm)
  • Frequency range: 40 to 48
    MHz
    (40-48 MC)
  • Channel spacing: 200 kHz
  • Channel Selection via "TUNING" control, channel display showing channel 0 (40.000 MHz) to channel 40 (48.000 MHz)
  • Modulation: FM voice
  • Vacuum tubes:
3A4 (2)
1T4 (6)
1L4 (5)
1R5 (1)
1A3 (1)
1S5 (3)
  • RF Power output: 0.3 watts
  • Frequency calibration (crystal oscillator) 4.3 MHz 10th harmonic (43.0 MHz) and 11th harmonic (47.3 MHz) marked on channel display - channel 15 (43.000 MHz) and halfway between channels 36 (47.200 MHz) and 37 (47.400 MHz)
  • Range: approximately 3 miles (4.8 km) (varied considerably with terrain, location of transmitter and receiver, and antenna used)

War Department Technical Manuals

  • TM 11-242 for Radio Set SCR-300-A (1945)
  • TM 11-983 for PP-114
    Vibrator power supply
    (1945)
  • TM 11-637 for AN/VRC-3 (1944)

See also

References

Wikimedia Commons has media related to SCR-300.
  1. ^ Magnuski, H. S. "About the SCR-300". SCR300.org. Retrieved 2 July 2016.
  2. ^ Niesel, John. "The SCR-300 Backpack Radio". warfarehistorynetwork.com. Sovereign Media. Retrieved 28 December 2018.
  3. ISBN 978-0-8117-4373-0
    . SCR-300 walkie talkie.
  4. ISBN 978-0-89434-119-9
    .
  5. ISBN 978-1-85109-732-6
    .
  6. ^ George Raynor Thompson; Dixie R. Harris (1966). The Signal Corps: the outcome (mid-1943 through 1945). Office of the Chief of Military History, U.S. Army. pp. 667–.
  7. ISBN 978-1-61060-744-5
    .
  8. ^ a b United States. War Dept (1945). Radio Set SCR-300-A, War Department Technical Manual TM 11-242. United States War Dept. Alt URL
  9. ^ "SCR-300 Backpack Radio". Olive-Drab.com. Olive-Drab.com. Retrieved 2 July 2016.
  10. ^ Electronics. McGraw-Hill Publishing Company. January 1945. pp. 2–.
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