Kenya, assisting an anti-aircraft Brigade in intercepting attacking Italian bombers, tracking them up to . During early 1941, six systems were deployed to East Africa and Egypt; JB systems were also placed at the four main South African ports. An improved system, designated JB-3, was built at the BPI; the most important changes were the use of a transmit-receive device (a duplexer) allowing a common antenna, and an increase in frequency to 120 MHz (2.5 m). The range increased to 150 km for aircraft and 30 km for small ships, with a bearing accuracy of 1–2 degrees. Twelve sets of JB-3 radars began deployment around the South African coast in June 1941. By mid-1942, British radars were available to meet all new South African needs. Thus, no further developments were made at the BPI. Most of the staff joined the military. Basil Schonland, as a Lt. Colonel in the South African Army, went to Great Britain to serve as Superintendent of the Army Operational Research Group and later the scientific advisor to Field Marshal Bernard Montgomery. See also History of radar References World War II radars Science and technology during World War II