Into production Chain Home

the first workable radar unit constructed robert watson-watt , team. 4 separated nt46 tubes can seen. production units largely identical.

the system deliberately developed using existing commercially available technology speed introduction. development team not afford time develop , debug new technology. watt, pragmatic engineer, believed third-best if second-best not available in time , best never available @ all. led use of 50 m wavelength, wilkins suggested resonate in bomber s wings , improve signal. however, meant system increasingly blanketed noise new commercial broadcasts began taking formerly high-frequency spectrum. team responded reducing own wavelength 26 m clear spectrum. s delight, contrary wilkins predictions, shorter wavelength produced no loss of performance. led further reduction 13 m, , ability tune between 10 , 13 m, in order provide frequency agility avoid jamming.

wilkins method of height-finding added in 1937. had developed system way measure vertical angle of transatlantic broadcasts while working @ rrs. system consisted of several parallel dipoles separated vertically on receiver masts. rdf goniometer connected 2 crossed dipoles @ same height , used determine bearing target return. height finding, operator instead connected 2 antennas @ different heights , carried out same basic operation determine vertical angle. because transmitter antenna deliberately focused vertically improve gain, single pair of such antennas cover thin vertical angle. series of such antennas used, each pair different center angle, providing continual coverage 2.5 degrees on horizon as 40 degrees above it. addition, final remaining piece of watt s original memo accomplished , system ready go production.

industry partners canvassed in 1937, , production network organized covering many companies. metropolitan-vickers took on design , production of transmitters, ac cossor did same receivers, radio transmission equipment company worked on goniometers, , antennas designed joint ames-gpo group. treasury gave approval full-scale deployment in august, , first production contracts sent out 20 sets in november, @ total cost of £380,000. installation of 15 of these sets carried out in 1937 , 1938. in june 1938 london headquarters set organize rapidly growing force. became directorate of communications development (dcd), watt named director. wilkins followed him dcd, , a. p. rowe took on ames @ bawdsey. in august 1938, first 5 stations declared operational , entered service during munich crisis, starting full-time operation in september.