Devices used to search for planes before the advent of radars (17 photos)

No, these are not devices for communicating with aliens: giant locators on the ears helped detect planes and airships.





Back at the end of the 19th century, Alexander Popov discovered that radio waves tend to be reflected. He conducted experiments on two ships, one of which had a radio receiver, and the other a radio transmitter. However, before this theory could be used anywhere (especially in military affairs), more than one decade passed. In fact, radar began to be used only during World War II. It was then that the first radars appeared, which could detect an enemy aircraft in the sky at a great distance using reflected radio waves. But how were aircraft found before the 1940s?



Dutch personal sound detector, 1930s

The difficulty was that it was possible to detect an object in the sky only by seeing or hearing it. During the First World War, airships were actively used as bombers, and the German Zeppelins had one great advantage: when approaching an object, the engine could be turned off and disappeared into the clouds. Therefore, it was necessary to detect it in the sky long before it reached its destination.

To detect enemies in the sky, unusual devices were created - sound detectors. Today they look very outlandish, but for the first half of the twentieth century they were real technical masterpieces, allowing you to hear an approaching airliner.

The first aircraft engines were very loud





However, even these sounds could only be heard from a fairly close distance.



But in order to hear them as far as possible, military engineers came up with listening devices



Dutch device, 1930s: it even had a chair for the operator to sit on



Sound detectors made it possible to detect sound or vibration high in the sky



And then, after analyzing this information, detect the location of the aircraft



Japanese Emperor Hirohito inspects three new locators



They were completely different in appearance: Perrin sound detectors from France, 1930s



Demonstration of a new device in Japan, 1932



All military engineers tried to improve the technology



The device consisted of large horns that were connected to the ears using tubes, USA, 1925



Such devices were used until the Second World War, until the first radars appeared.



Sound locating device in Germany, 1939



Such devices could detect a target at a distance of 5 to 12 km, depending on the weather and operator experience



Swedish soldiers in 1940