World War Two

A concentration on military communication and navigation.

During the Second World War STC concentrated on producing military radar and radio navigation equipment, bomb guidance devices and ground-controlled aircraft landing systems. In 1941 STC designed an interception airborne radar (radar used by an aircraft to locate and track other aircraft). At the end of 1942 the RAF began using the Oboe ground control blind bombing and marking system, developed by employee Alec Reeves at the Telecommunications Research Establishment.

STC also established the basic manufacture of selenium rectifiers which had previously been imported. Selenium rectifiers were used to convert alternating current to direct current in devices such as radios, battery chargers and aircraft engine starters. STC's output of rectifier discs expanded from half a million in 1939 to 23 million in 1944.

As STC’s plants were concentrated in London they were vulnerable to enemy bombing and arrangements were made to protect the production of important products and components. When there was a serious threat of invasion all the drawings for the company’s major production line, Strowger telephone exchanges, were copied and shipped to the Bahamas. Shadow factories were also set up outside of London. Various sites suffered bomb damage and lives were lost due to V1 bombs falling at the company’s then headquarters at Connaught House and at the New Southgate site.

During the war STC supplied 55 broadcasters which were used to transmit programmes to newly liberated countries and to entertain the troops. Broadcasters were shipped to countries including Belgium, China, India, Iran, Malta, the Netherlands and South Africa. The bulk of the company's effort was however directed at military communications. Since before the war it had been working on the Defence Telecommunications Network, a telephone and teleprinter network linking home defences. In the field of navigation, what had been the German designed Lorenz beam approach system for aircraft navigation was redeveloped and named the Standard Beam Approach. STC made 386 ground beacons and some 36,0000 airborne receivers which indicated if a plane was on course, or to the left or right of it.   

Towards the end of the war there was a major reduction in STC’s manpower from nearly 24,0000 in 1944 to 16,000 in 1945. The company now had to readjust its operations to peacetime products and demand levels. 1945 saw the opening of a new STC site at Newport in South Wales for the manufacture of cable and transmission equipment. In the post war period STC also became involved in television, installing a coaxial cable between London and Birmingham and putting the first portable microwave links on trial with the BBC. In 1946 ITT set up a new research unit, Standard Telecommunication Laboratories (STL), initially based at Enfield in North London. 

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Top image: aircraft equipment undergoing testing in a 'hot box' to recreate jungle humidity, 1945 (NAEST 211/2/12/2 D.3843)

Bottom image: staff at work on shell velocity measuring equipment in an advanced development laboratory, 1945 (NAEST 211/2/26/3 D. 3866)

Black and white photograph of aircraft equipment in a hot box to create humidity, 1945 (NAEST 211/2/12/2 D.3843)  

Black and white photograph of the advanced development laboratory, men working on shell velocity measuring equipment, 1945 (NAEST 211/2/26/3 D. 3866)