Comments on: That new secret gadget is all right https://www.isegoria.net/2013/07/that-new-secret-gadget-is-all-right/ From the ancient Greek for equality in freedom of speech; an eclectic mix of thoughts, large and small Thu, 21 May 2026 16:19:21 +0000 hourly 1 http://wordpress.org/?v=3.6.1 By: William Newman https://www.isegoria.net/2013/07/that-new-secret-gadget-is-all-right/comment-page-1/#comment-897855 William Newman Tue, 09 Jul 2013 23:41:07 +0000 http://www.isegoria.net/?p=32036#comment-897855 Radar detection of aircraft is an easy mental jump, but some of the practicalities of radar detecting distant aircraft, especially from ground stations, are probably not easy to understand unless you just try it and see. Even with a pretty good computer and accurate data on material properties, it’s not so easy to calculate radar cross sections of nontrivial shapes, especially when the wavelength is of the same order of magnitude as the features of the plane or the landscape feature. It’s not ridiculously difficult like various nonlinear partial differential equations that arise in fluid mechanics, but not a calculation that’s easy to do on a napkin either. I think it would be rather tricky to estimate from first principles how much aircraft echoes would stand out from echoes scattered from the landscape.

The practicality of radar reflections for proximity fuzes seems conceptually easy, though. You might not be sure you could make economical rugged electronics that fit in a shell, but you could be pretty sure that if you could make the electronics, the waves should bounce cleanly enough to make a pretty effective weapon.

]]> By: David Foster https://www.isegoria.net/2013/07/that-new-secret-gadget-is-all-right/comment-page-1/#comment-897752 David Foster Tue, 09 Jul 2013 21:54:48 +0000 http://www.isegoria.net/?p=32036#comment-897752 In a used bookstore a couple of years ago, I picked up a copy of an aviation magazine from March 1939. The “Aircraft Radio” column mentions a new invention called a Klystron, used to generate ultra-high-frequency radio waves. Two applications for such frequencies are mentioned: instrument landing systems and the United Airlines-Western Electric Terrain Clearance Indicator. The column mentions that both of these systems had been profiled in earlier issues.

The TCI was a radio altimeter, ie basically radar, albeit radar with a very short range and providing distance but not azimuth information. I would think it would have been an easy mental jump for anyone to go from radio waves for detecting the ground and the distance therefrom, to the use of radio waves for the detection and ranging of aircraft.

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