The SCR-277 was a mobile, trailer mounted radio range set for radio guidance of

aircraft An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines. ...

. It was standardized by the U.S. Army in June 1941. K-29_trailer_for_SCR-277_radio_navigation

Specifications

The SCR-277 was used as a navigation aid. It included the BC-467

transmitter In electronics and telecommunications, a radio transmitter or just transmitter is an electronic device which produces radio waves with an antenna. The transmitter itself generates a radio frequency alternating current, which is applied to ...

with an RF output power of 800

watt The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after James Wa ...

s, the BC-468

Goniometer A goniometer is an instrument that either measures an angle or allows an object to be rotated to a precise angular position. The term goniometry derives from two Greek words, Wikt:γωνία, γωνία (''gōnía'') 'angle' and Wikt:μέτρο ...

, and

BC-342 The BC-342 was a World War II U.S. Army Signal Corps high frequency radio receiver. It was used primarily as part of field installations such as the SCR-188A, but could be used with mobile sets such as the 2 1/2 ton mounted SCR-399. First designed ...

receiver. Frequencies utilized were 200-400

kHz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one h ...

for transmission and 1.5-18

MHz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one h ...

for reception. Radio range homing equipment transmitted tone identification signals to aircraft that lacked a

radio compass Direction finding (DF), or radio direction finding (RDF), isin accordance with International Telecommunication Union (ITU)defined as radio location that uses the reception of radio waves to determine the direction in which a radio stat ...

but were equipped with command sets. Range was approximately 300 miles. It was powered by a single PE-90 generator.

Use

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.

References

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

External links

TM 11-487
Technical Manual. Electrical Communication Systems Equipment, 2 October 1944
SCR and BC lists
US Army Fort Gordon Military Museum Military radio systems of the United States Military electronics of the United States Air traffic control Radio navigation Surveying Wireless locating Equipment of the United States Air Force World War II American electronics Military equipment introduced from 1940 to 1944 {{Tech-stub

Specifications

Use

See also

References

General references

External links