development. Two promising experimental systems were developed. A VHF set designated Bistro (Rapid) and the microwave Burya (Storm). The best features of these were combined into a mobile system called Ulavlivatel Samoletov (Radio Catcher of Aircraft), soon designated RUS-1 (РУС-1). This CW, bi-static system used a truck-mounted transmitter operating at 4.7 m (64 MHz) and two truck-mounted receivers. In June 1937, all of the work in Leningrad on radio-location stopped. The Great Purge of Joseph Stalin swept over the military and the scientific community, resulting in nearly two million executions. The SCB was closed; Oshchepkov was charged with "high crimes" and sentenced to 10 years at a Gulag. NII-9 was also targeted, but was saved through the influence of Bonch-Bruyevich, a favorite of Vladimir Lenin in the prior decade. NII-9 as an organization was saved, and Bonch-Bruyevich was named director. The purges resulted in a loss of more than a year in development. RUS-1 was tested and put into production in 1939, entering limited service in 1940, becoming the first deployed radio-location system in the Red Army. Bonch-Bruyevich died in March 1941, creating a leadership gap, further delaying CW radio-location developments. The Nauchnoissledovatelskii ispytatelnyi institut svyazi RKKA (NIIIS-KA, Scientific Research Institute of Signals of the Red Army), that had originally bitterly opposed radio-location technology, was now placed in overall control of its development in the Soviet Union. They co-opted Oshchepkov's pulsed system, and by July 1938, had a fixed-position, bistatic experimental array that detected an aircraft at 30-km range at heights of 500 m, and at 95-km range for targets at 7.5 km altitude. The project was then taken on by Ioffe's LPTI, resulting in a system designated Redut (Redoubt) with 50-kW peak-power and a 10-μs pulse-duration. The Redut was first field tested in October 1939, at a site near Sevastopol, a strategic Black Sea naval port . During 1940, the LEPI took control of Redut development, perfecting the critical capability of range measurements. A cathode-ray display, made from an oscilloscope, was used to show range information. In July 1940, the new system was designated RUS-2 (РУС-2). A transmit-receive device (a duplexer) to allow operating with a common antenna was developed in February 1941. These breakthroughs were achieved at an experimental station at Toksovo (near Leningrad), and an order was placed with the Svetlana Factory for 15 systems. The final RUS-2 had pulse-power of near 40 kW at 4 m