Above, Dr. Hans Eric Hollmann is consulting for the GEMA Company where he helped  design the first modern radar sets. He had over 300 patents to his name. 76 of these  patents were filed in the US by the Telefunken Company for which he consulted.  Telefunken built the Wuerzburg radar sets which used  most of H. E. Hollmann's inventions.   Working in his company "Laboratory for High Frequency and Electromedecine," which  employed 20 scientists, Hollmann developed the high frequency technology which led to  the development of radar.

Two men, von Willisen and Paul Erbsloeh had founded the GEMA Company. In Erbsloeh's memoirs about von Willisen he writes, "With much work we were able to make the magnetron oscillate at 50 cm. The modulation at other frequencies with sound reception was made possible with the push-pull Barkhausen tubes from Hollmann." "Hollmann was our consultant and based on his experience measuring the heaviside layer he used pulsed modulation and used a CRT for all displays. At first the Marines were not enthusiastic about using the CRT aboard ships, but it was demonstrated that this was only right thing to do."  Hollmann invented a large number of early magnetrons which can be seen by clicking on  magnetrons. Most of the radar sets built throughout the world, during the 1930's and early  1940's, used H.E. Hollmanns ideas which are documented in his patents. The first modern Cathode Ray Tubes, CRTs, were invented and built by Manfred von Ardenne  who was a close friend of Hollmann and who also had a research lab located in Lichterfelden,  Berlin, across from Hollmann's lab. Click here to see his work on the CRT In 1929, Watson Watt visited the Lichterfelde labs of Hollmann and von Ardenne and purchased several hundred CRTs over the years. In 1935, H. E. Hollmann wrote the first comprehensive books on microwaves. The books are titled "Physics and Technique of Ultrashort Waves." The books were used in all countries of the world and it fueled the development of radar in all of the major countries in the world. His book showed examples of applications of microwaves. These books are still available in most libraries around the world. Copies can still be purchased, click here. What others say In a book by R. Buderi "The Invention that Changed the World" it is stated  that in 1935 the British read Hollmann's book in which his "assertion that cat's whisker crystals  constituted the best high frequency detectors. Thus the British radar effort started fortuitously  down the semiconductor path."S.S. Swords in his book "Technical history of the beginnings of  RADAR" writes about the US radar effort, "It is pertinent to point out that microwave propagation  tests continued into 1935 with the use of the German built Hollmann valves (retarding field tubes)." In another book by L. Brown "A Radar History of World War II" it is stated that Hollmann's book  "Physics and Technique of Ultrashort Waves" became the ultimate authority for microwaves until  the end of the decade." He also writes about Hollmann as being "Germany's - and until recently  Europe's - leading microwave specialist." In addition to writing his famous two volume books on "Physics and Technique of Ultrashort  Waves," he also wrote over 100 articles in the field of VHF. A list of these is shown in  Publications. After WWII he and his family came to the USA under "operation paper clip."   The secret service documented his life's work which can be reviewed under  Resume.