The SCR-277 was a mobile, trailer mounted radio range set for radio guidance of aircraft. It was standardized by the U.S. Army in June 1941.


The SCR-277 was used as a navigation aid. It included the BC-467 transmitter with an RF output power of 800 watts, the BC-468 Goniometer, and BC-342 receiver. Frequencies utilized were 200-400 kHz for transmission and 1.5-18 MHz for reception. Radio range homing equipment transmitted tone identification signals to aircraft that lacked a radio compass but were equipped with command sets. Range was approximately 300 miles. It was powered by a single PE-90 generator.[1][2][3]


In operation the transmitter sends out signals coded "A" or "N" in each of the four quadrants around the beacon. The signals overlap on the range, providing the pilot of the aircraft an indication of his position in relation to location of the beacon. Thus, if he is heading toward the beacon he will receive an aural signal coded "A" or "N" if he is between the beam, and when he is on the beam he will receive "AN" signal. Over land areas the beacon has a range of about 300 miles, while over water areas the range is extended to about 1,000 miles. Charts prepared for air navigation show the position and the orientation of the various beacons.[3]

See also


  1. "DIRECTORY OF SCR ITEMS". US Army Fort Gordon. US Army. Archived from the original on February 5, 2009. Retrieved 9 January 2019.
  2. 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; [for sale by the Superintendent of Documents, U.S. Govt. Print. Off.]. pp. 652–.CS1 maint: extra punctuation (link)
  3. "Graphic Survey of Radio and Radar Equipment" (PDF). Walt Gromov's Radio Museum. Army Air Forces, Air Technical Services Command. Retrieved 9 January 2019.

General references

  • TM 9-2800 Standard Military Motor Vehicles. dated 1 September 1943
  • TM 9-2800 Military vehicles dated October 1947
  • TM 11-227 Signal Communication Directory. dated 10 April 1944
  • TM 11-487 Technical Manual. Electrical Communication Systems Equipment, 2 October 1944
  • SCR and BC lists US Army Fort Gordon Military Museum

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