Hans Erich Hollmann

from Wikipedia, the free encyclopedia

Hans Erich Hollmann (born November 4, 1899 in Solingen ; † November 19, 1960 in Los Angeles ) was a German physicist and engineer who succeeded in several decisive developments in the field of radar technology .

Life

Hans Erich Hollmann was born in Solingen as the son of the physician Peter Hollmann. He attended high school in Solingen and was already interested in radio and radio technology as a teenager. In the last days of the First World War he was captured by the French and did not return to Germany until the beginning of 1920. Then he began studying electrical engineering at the Technical University of Darmstadt and received his doctorate in 1928 as Dr.-Ing. with the topic of the mechanism of Barkhausen electron oscillations .

In 1927 he developed and built the first VHF transmitter and receiver for the centimeter and decimeter wave range at the Physics Institute of the TU Darmstadt . This led to the development of the first microwave - telecommunications system . A magnetophone with two scanning heads for generating pseudostereophony was also developed at that time.

From 1928 to 1930 he worked for the German Research Foundation and dealt with ultra-short and decimeter waves. In 1930 he moved to the Heinrich Hertz Institute for Vibration Research in Berlin. As an assistant he worked on microwaves and cathode ray tubes , as part of the II. International Year for Polar Research 1932/1933 he devoted himself to ionospheric research and radio astronomy . In 1933 he became a lecturer at the Technical University in Berlin , the subject of his habilitation was the ultradynamic vibration amplification through feedback . He also worked as a consultant at Telefunken in the field of ultra-short wave and general high-frequency technology, where a large number of his patents were created.

In 1934 Hans Erich Hollmann was involved as an advisory board member in the founding of GEMA , the Society for Electroacoustic and Mechanical Apparatus mbH . In 1934, GEMA built the first pulse ship radar device using a microsecond pulse generator created during a polar expedition , which worked with a 50 cm wavelength and could detect ships up to 10 km away. From 1935 to 1937 Hollmann worked as a research assistant for radio measurement technology at GEMA. In 1935, GEMA also developed two areas of application, on the one hand the marine radar device Seetakt , which was operated with a wavelength of 80 cm, and on the other hand the land-based radar system Freya . The buyers were always the Navy .

Telefunken began developing radar in 1933 on the basis of the research and work of Hans Hollmann, and the "Darmstadt" radar device or, in its successor, the "Würzburg" device was presented. During the Second World War , the Freya radar and the Würzburg radar, which was equipped with a good directional characteristic, were often used together. With the Freya flight direction finding device, the incoming aircraft were recorded at a great distance, and the Würzburg flight targeting device was then used to determine the exact directional angle and distance information.

In 1935, Hans Hollmann published an important work on microwaves , the physics and technology of ultra-short waves in two volumes. The second volume deals with microwave telemetry and contains the groundbreaking chapter "Vision with electromagnetic waves". However, certain details (e.g. echo time measurement with a cathode ray tube ) were not allowed to be published due to objections from the Navy. Both volumes received the attention of researchers all over the world and provided inspiration for the development of centimeter wave radars . Even without knowledge of the unpublished parts, William D. Hershberger of UCLA , for example , who played an essential role in the development of radar (for example SCR-270 ) in America, considered the findings described to be so important that they could also be compared to the American Advise government in a memorandum on radar development.

In 1930 Hollmann founded his own company, the "Laboratory for High Frequency Technology and Electromedicine" at Gärtnerstrasse 13 in Berlin-Lichterfelde , where he conducted research on high frequency technology, ultra-short waves and microwaves. Together with his brother, the physician Werner Hollmann , new electrocardiography acquisition methods were developed. During this time Werner Reichardt became his most important student.

During the war he continued to work with 20 scientists in his own laboratory on orders from Telefunken and GEMA. a. on an order from the OKH for “research into radio transmitters to interfere with radar systems”.

In 1942 he also worked as director of the Research Institute for Radio and Sound Film Technology in Berlin in the fields of high and low frequency technology , acoustics , photography and film. In this role he supervised several research institutes in occupied countries during the war and saved some scientists from deportation to Germany (for example by awarding research contracts that were described as important to the war effort).

After his laboratory was destroyed in a bombing raid in 1942, it was moved to Georgenthal in Thuringia . The activities there covered a wide range of technology: apparatus for measuring the efficiency of induction heating, pulse generator for metal hardening, a lightweight microwave distance measuring device, development of a rapid process for drying glue, a laboratory geiger counter, a vibration display device, process for the automatic coordination of transmitters and receivers and much more more.

After the war it was no longer allowed to do research in the field of microwaves, so he turned to other areas of electronics. From 1945 he carried out research on transmission technology for the central works in Bleicherode and in 1946 he worked as a scientific consultant for frequency modulation and television technology at the Arnstadt plant of Siemens & Halske . In 1947 he became professor for high-frequency and electromedicine at the University of Jena . Since Thuringia had been in the Soviet-occupied zone of Germany since 1945, he continued his activities in California ( Operation Paperclip ) on the basis of an offer from the government of the USA or the request of the US Navy .

His research area now extended to transistor technology , including again in high-frequency and high-frequency energy in high-power transmitters, as well as photovoltaics and tandem transistors. He became director of the research area at Dresser Industries in California and, in this role, dealt with the conversion of heat, solar and atomic energy into high and low frequency alternating current. Also because of his diverse successes and achievements in the field of electronics and medical electronics, he was awarded membership as a "Fellow" in the "Institute for Radio Engineers" in 1952.

In 1957 he was awarded an honorary doctorate by the Technical University of Dresden .

He was married to Gisela Schimmelbusch and had three children.

Patents

Structure of the anode of the multi-chamber magnetron for which Hollmann has applied for a patent

Hollmann applied for the patent "Radio Apparatus for Determining Distance and Direction" in Germany in 1935 and in the USA in 1936, which was granted to him in 1939 with the number 2151323 in the USA. The multi-chamber magnetron was applied for on November 29, 1935 and granted as a patent numbered 2123728 on July 12, 1938. The two-dimensional echo display on the screen of the cathode ray tube of radar devices ( PPI Scope Plane Position Indicator) is also associated with his name and that of Manfred von Ardenne . In total, Hollmann has approximately 300 electrical engineering and physics patents, 76 of them in the United States.

Publications

Hans Erich Hollmann published scientific articles in the field of high frequency technology, ultra-short and microwave waves and about electromedicine.

literature

Web links

Individual evidence

  1. ↑ Honorary doctoral students of the TH / TU Dresden. Technical University of Dresden, accessed on February 9, 2015 .
  2. ↑ Magnetron patent on radarworld.org, viewed May 5, 2010 (English)
  3. ↑ CRT patents on radarworld.org, accessed May 5, 2010
  4. ↑ List of 76 US patents from 1930 to 1938 on radarworld.org, accessed May 5, 2010 (English)
  5. ↑ List of 82 scientific publications on radarworld.org, viewed May 5, 2010 (English)
personal data
SURNAME Hollmann, Hans Erich
ALTERNATIVE NAMES Hollmann, Hans E .; Hollmann, Hans; Hollmann, Hans Eric
BRIEF DESCRIPTION German engineer
DATE OF BIRTH November 4, 1899
PLACE OF BIRTH Solingen
DATE OF DEATH November 19, 1960
Place of death los Angeles