Milestones:Zenit Parabolic Reflector L-band Pulsed Radar, 1938
Zenit Parabolic Reflector L-band Pulsed Radar, 1938
The 1938 Zenit radar test at the Laboratory of Electromagnetic Oscillations of the Ukrainian Institute of Physics and Technology was a major advance in the development of radar. Designed by Abram Slutskin, Alexander Usikov, and Semion Braude, microwave scientists and magnetron pioneers, Zenit established the practicality of combining the pulsed method and a shorter wave band for determining precisely all three coordinates of airborne targets.
Street address(es) and GPS coordinates of the Milestone Plaque Sites
4, Svobody Sq., Kharkiv, Ukraine, 61022, on the third floor near rector's office and entrance to the School of Radio Physics, Biomedical Electronics, and Computer Systems, coordinates 50.004022, 36.228348.
Details of the physical location of the plaque
On the third floor near rector's office.
How the intended plaque site is protected/secured
As the plaque is supposed to be placed on the outer wall, the plaque will be accessible for all visitors and public.
Historical significance of the work
As to the regional and national Ukrainian development, one can state that Zenit work performed in Kharkiv in the 1930’s served as a cradle for the whole microwave, antenna, and radar community in Ukraine [1-7]. The group of talented microwave and radar scientists was headed by Prof. A. Slutskin, who was inventor of a very successful L-band split magnetron first reported by him as early as 1926, and the initiator and leader of the Zenit project. His staff members and former students A. Usikov and S. Braude discovered the pulsed operation of magnetron, and were responsible for the transmitter and receiver units of Zenit, respectively. Later Usikov and Braude were the founders of the Institute of Radio-Physics and Electronics of the National Academy of Sciences of Ukraine (IRE NASU, 1955) and the Institute of Radio Astronomy (IRA NASU, 1985) in Kharkiv.
Thanks to successful development of L-band magnetrons and Zenit in the 1930’s and mm-wave magnetrons in the late 1940’s, other important establishments were opened in Kharkiv after WW II. To mention only a few, these were the USSR Military Academy of Radio Engineering (1947), the School of Radio Physics at the Kharkiv National University (1952), the Kharkiv National University of Radio Electronics (1963), and the Hartron Space Control Systems Industry (1960). All these establishments and their offspring are at the core of today science and technology in the electromagnetic waves and their applications in the independent Ukraine . Since then, Kharkiv has become and remains the major Ukrainian center of research into microwaves, millimeter waves, and sub-millimeter waves.
Still the work on Zenit should be evaluated separately in relation to the USSR technological developments as Ukraine had been a part of that country until 1992. In the scope of the USSR, Zenit technology clearly demonstrated the strength and merits of combined use of shorter-than-usual for the late 1930’s waves and the pulsed method, in the determination of all three coordinates of the flying aircraft. A crucial evidence of the role played by Zenit is found in the capital Soviet source on the history of national radar – the book of Gen. M. Lobanov  who was supervising all gun-laying radar works before and during WW II.
Here, it must be noted that an earlier journal article of M. Lobanov was extensively cited in the famous work of J. Erickson  and his later book chapter , where the development of Zenit was also mentioned, together with its test in October 1938. That article, published in 1962, was a precursor to Lobanov's much more comprehensive book  published in 1973.
It must be also emphasized that the negative evaluation of Zenit given in the generally well documented and in all other aspects accurate book of Louis Brown  with a reference to the book of Lobanov is erroneous. Lobanov had devoted three full pages to Zenit, described this achievement with strong sympathy and concluded with very high evaluation. It is apparent that, unlike Erickson's thorough study of preceding Lobanov's article, L. Brown never read the book of Lobanov and used apparently only a poor quality translation of selected pages.
This overlook has been corrected and important role of Zenit has been fully acknowledged in the later published encyclopedia of radar history worldwide of Raymond Watson  – see pp. 292-296.
For the international technological development, Zenit remained largely unknown and had little or no impact. Still there exists a certain mystery. There is an article in the Ukrainian newspaper “Evening Kharkiv” dated 2000  stating that the German intelligence, apparently political service SD, was aware of that work in Kharkiv and put some efforts to obtain information about it. The journalist claimed that in the 1970’s he was told by the pre-war and wartime Soviet minister of communications, Signal Corpse Marshal I. Peresypkin that the latter had a copy of the German intelligence report bearing the handwritten note of Hitler ordering to send the best spies to Kharkiv for radar intelligence. This interest could be connected to the work in Germany on a similar system later known as Wurtzburg radar (wavelength 53 cm, 3-m parabolic dish antenna).
Today one can also state that besides of above-mentioned points, the success of Zenit demonstrated one other principle of deep social meaning. The highly innovative R&D, even in defense-related area, has better chances for a rapid progress at a civil laboratory rather than at a military one. This was never admitted in the highly militarized and infested with spy-mania USSR, however was well known circumstance in the UK and USA, where famous civil organizations such as the Telecommunications Research Establishment and the Radiation Laboratory at the Massachusetts Institute of Technology, respectively, had played crucial role in the acceleration of radar developments during the WW II [see, e.g., IEE Proc. A, Special Issue on Historical Radar, vol. 132, no 6, 1985; R. Buderi, The Invention that Changed the World, NY: Touchstone, 1997].
Features that set this work apart from similar achievements
The work on Zenit was on the mind of A. Slutskin since 1935, officially started in March 1937, and lasted, with breaks, till the end of 1940. The date of October 14, 1938 should be paid a special attention as that day, according to S. Y. Braude, the first successful field-test of Zenit was performed in Kharkiv demonstrating the ability to accurately determine all three coordinates of a flying airplane [1,2,5]. Importance of that event was tremendous as apparently all radars in service and in development that existed at that moment (i.e., British Chain Home, German Freya and Seetakt, Soviet Burya, Rapid and Redut, and Doppler radar prototypes developed at the Tohoku University, Japan and in the laboratory of Marconi in Italy) were able to determine the azimuth of the target and either its range or elevation, while the third coordinate remained essentially undetermined. Zenit was able to overcome this drawback thanks to the lucky combination of two principal innovations: it used pulsed method and worked with shorter than common waves of the 60-65 cm wavelength.
Pulsed method itself was not absolutely new as it was first tested in Germany (Lorenz Co.) in 1936 and in the UK, USA (L. Young and R. Page), and USSR (M. D. Gurevich, Jr. [8, p.52]) even earlier, in 1934. However by 1938 it had gained no significant attention of the military and civilian customers both in the USSR and abroad. Important exception was apparently the UK Chain Home early-warning network using the pulsed method from the start; however its ability to determine the target range and bearing was greatly degraded by the small resolution because of the 26-m (1936) to 10-m (1939) wavelength. The USSR experts then commonly viewed the continuous-wave principle of radar as more promising [1,4,8]. Initiative of Zenit development came from a civilian R&D laboratory, which was eager to explore the opportunities given by a freshly discovered pulsed mode of their original L-band split-anode magnetron operation. In this aspect Zenit was a champion – it was apparently the first ever radar with a pulsed magnetron source although the German Wurtzburg engineers had tried magnetrons at approximately the same period.
Decimeter (L-band) waves were also actively studied at that moment in many countries. Anyway at the time of its first test Zenit apparently had the most powerful decimeter-wave source of 3 kW in the world, and by 1940 it used the source of 17 kW. Indeed, the cavity magnetron at the 9.8-cm wavelength was invented in the UK in the beginning of 1940, improved for 10-kW power by the end of 1940, and used in radars since 1941.
Before that, in the UK the Chain Home network operated with 26 m to 10 m wavelengths, and AMES-2 radar working with 1.5 m waves, for the Chain Home Low, appeared only in the end of 1939; in the USA experimental 50-cm gun-aiming radar was developed by the Bell Laboratories only in 1940; in Germany the prototypes of the early-warning radar Freya and naval radar Seetakt used 2.4 m and 80 cm wavelengths, respectively, while radar Wurtzburg working with a shorter, 53 cm, wavelength had not appeared before 1939 or 1940; and in Japan the waves shorter than 10 m and pulse method was apparently not applied in radar studies at all until 1941 - see  and also IEE Proc. A, Special Issue on Historical Radar, vol. 132, no 6, 1985; R. Buderi, The Invention that Changed the World, NY: Touchstone, 1997.
1. J. Erickson, "Radio-location and the air defence problem: The design and development of Soviet radar 1934-40," Science Studies, vol. 2, pp. 241-268, 1972.
2. J. Erickson, Chapter 16 in Radar Development to 1945, ed. by R. Burns, Peter Peregrinus/IEE Publ., 1988.
3. S.S. Swords, Technical history of the beginnings of Radar, Peter Peregrinus/IEE Publ., 1986, section 4.7.
4. A.A. Kostenko, A.I. Nosich, I.A. Tishchenko, “Development of the first Soviet 3-coordinate L-band pulsed radar in Kharkov before WWII”, IEEE Antennas Propagat. Magazine, vol. 44, no. 3, pp. 28-49, 2001. [attached]
5. A.A. Kostenko, A.I. Nosich, I.A. Tishchenko, “Radar prehistory, Soviet side: development of the first 3-coordinate L-band pulse radar in Ukraine in the late 1930’s”, IEEE Antennas Propagat. Symp. Digest, Boston, vol. 4, pp.44-47, 2001.
6. A.I. Nosich, Y.M. Poplavko, D.M. Vavriv, F.J. Yanovsky, “Microwaves in Ukraine”, IEEE Microwave Magazine, vol. 2, no 4, pp. 82-90, 2002. [attached]
7. A.I. Nosich, A.A. Kostenko, "In the labor people's name: development of 60-kW magnetrons in the artificial famine plagued Ukraine in the early 1930s," Proc. Int. Conf. Origins and Evolution of the Cavity Magnetron (CAVMAG-2010), Bournemouth, pp. 82-88, 2010. [attached]
8. M. Lobanov, The Beginning of Soviet Radar, Moscow, Sov. Radio Publ., 1973 (in Russian).
9. V. Artemenko, "Watched by Muller," Newspaper “Vecherny Kharkov” (Evening Kharkov), no 128 (8189), page 4, 16.11.2000 (in Russian with translation). [attached]
10. L. Brown, A Radar History of World War II: Technical and Military Imperatives, Taylor and Francis Publ., 1999.
11. R. C. Watson, Jr., Radar Origins Worldwide: History of Its Evolution in 13 Nations through World War II, Victoria, Trafford Publ., 2009.