Acoustic Radar

Posted: Wed Apr 29, 2009 11:21 pm

Scattered around the South East coast of England are these concrete objects. They are Acoustic Mirrors, built from 1916 to the mid 1930’s as an acoustic early warning system . The mirrors were simply large "acoustic ears" used to locate approaching enemy airplanes and Zeppelins by amplifying and pinpointing engine sound - they had a range of around fifteen miles which gave a few minutes extra warning over visual location . The parabolic mirrors reflected and focused the sound into one spot which was picked up by the listener through a rubber tube attached to the ears - a great example of the practical application of British eccentricity. The mirrors eventually became obsolete with the development of faster aircraft and killed off entirely with the invention of Radar.

Mobile versions of the sound mirrors were still in use by Germany, Britain and the USA during the Second World War as crude anti aircraft warning devices:

German Acoustic Early Warning device (1940s)

British Acoustic Early Warning device (1940s)

...and my favorite the Japanese Mobile Acoustic Horns (1930s)

http://crab.wordpress.com/2008/01/

Posted: Wed Sep 09, 2009 11:02 am

here is interesting demo of how acoustic radar worked within the british air defense network

Posted: Wed Sep 23, 2009 6:43 pm

the "predictor" got me curious so here's one on that, kind of interesting.