"Accoustic Ears" Air Craft Detection before Radars

Following the First World War in which Acoustic detection had been used against attacking aircraft in France experiments were carried out across the South and South-East of Britain’s coasts.
The system was effective in principle and the large parabolic dishes focused the incoming parallel sound ‘rays’ to a single point at which a listening device could be positioned. In calm air conditions a range of about 15 miles (25 km) could be achieved but the speed (350 kph) of the aircraft in existence when the system was eventually abandoned was such that only about 4 minutes warning of approach could be given.



Concrete and steel acoustic domes dating from the early 1920’s in fixed positions above Romney Marshes on
Britain’s South Coast.
A chain of these ran from Hythe all the way round to the Thames Estuary, with a few others positioned inland at major airfields like Hendon & Biggin Hill.


This earlier version ( left ) from just after the
First world war period - through to the Japanese version (above) showed that the thinking behind the technology did not really changed. In fact the electronic device of Christian Huelsmeyer had a far
more scientific principle and clearly much greater potential than these. It is hardly surprising that RADAR developed as it did. By early 1936 it was becoming clear that developments in radio transmissions and direction sensing (see Dr Hans E Hollmann) through the work of scientists working with short wavelength radio direction finders that the use of audio-detectors had little future. However as an illustration of the rapid progress that can be experienced in science and technology in only a decade the concrete dishes and wheeled trolleys are a monument to ingenuity and innovation in times of need – despite their ultimate failure.

Great

great mirza nice information

wow see how technology evolves....

Thanx TPS and Majoka
@ Ajay as we know all countries of world are now having Latest Radar System some of them are using Satellite with Radars but still no one is Able to catch US Stealth Technology!!! Stealth Helicopters can fly in your Air and Radar will be sleepy during this fly time...

yes i know that they have made submarines that are not detected by sonar system can you beat that??

they absorb the incoming sound by some special coating on the submarine wall. and on the top side of submarine they have their stealth technology same that is used for air planes, so that if sub comes out of water it should not be detected by any radar.