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About RF Cafe
Copyright: 1996 - 2024 BSEE - KB3UON RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while typing up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived... All trademarks, copyrights, patents, and other rights of ownership to images
and text used on the RF Cafe website are hereby acknowl My Hobby Website: |
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Aircraft Detection Prior to the Invention of Radar
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Cool Pic Archive Pages | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | These images have been chosen for their uniqueness. Subject matter ranges from historic events, to really cool phenomena in science and engineering, to relevant place, to ingenious contraptions, to interesting products (which now has its own dedicated Featured Product category). Beginning in the middle of the 1930s, engineering labs in the U.S. and Europe were experimenting with radar systems. Early radars did not have the slick plan position indicator (PPI) displays that modern systems use for plotting target movement for indication of azimuth (direction) and range (distance). Instead, oscilloscopes showed radar returns as amplitude blips along a time base that represented range. Azimuth was determined by where the operator pointed the antenna (rotating versions came later). Since radar cross section stealth technology had not been invented yet, the amplitude of the signal was useful a measure of the size of the target. Prior to the invention of radar (RAdio Detection And Ranging), other means were needed to detect approaching aircraft during times of war. Human spotters were often posted in open fields, tall building rooftops, shorelines, and hills in order to provide a measure of warning against approaching enemy aircraft (acoustic defense). Effectiveness was dependent on many parameters like quality of eyesight, hearing and alertness of the observers, atmosphere transparency (visibility), light level, aircraft size, configuration, color and noise level, etc. Even under ideal conditions detected aircraft would be no more than a few minutes away from the observer, so that did not leave a lot of time to prepare a response. Observer networks were set up as far in advance of key targets as possible through a radio relay network, but it left a lot to be desired. That's where the strange, often Dr. Seuss-looking listening devices shown below were designed and employed to aid the observers. These photos are all over the Internet, so I do not know their origins. I will be glad to credit the true owner(s) if contacted, and will provide a hyperlink to the originals. Thanks to Bob D. for letting me know about them.
The douglas-self.com web page link was sent to me after posting these pictures. It has more information on these pictures. You'll probably enjoy perusing some of the other topics he has as well. Here is a page on early radar development. See the Homemade Plane Detector article from the May 1942 Popular Science magazine.
Posted March 29, 2019 |
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