Amazed the devices that detect enemy aircraft before the radar

Today, thanks to the help of radar systems, it is easy to detect the movement of aircraft. But before radar technology, how do people detect the movement of aircraft? Certainly many people will be surprised to learn that, at that time, people mainly relied on their eyes and ears.

These giant headphones facing the sky like this were the method of detecting aircraft before the Radar device was invented in 1917. (Photo source: Rare).

To increase mobility, soldiers are equipped with smaller devices but they cannot be as effective as giant sound amplifiers placed on the ground.(Photo source: Rare).

The soldier uses his ears to listen and find the direction of enemy aircraft thanks to the sound the amplifier system records.(Photo source: Rare).

The distance to detect enemy aircraft can range from a few hundred meters to tens of kilometers depending on the system.But the effectiveness of these systems is influenced by user hearing and weather conditions.If it is raining or there is a strong wind, the soldier will not be able to "hear" the sound of enemy aircraft due to too many noise.(Photo source: Rare).

Locator Czech 2 stereoscopic sound locator in 1920. (Photo source: Rare).

Before 1940, every major army in the world used these rather bulky and annoying devices, which were not reliable enough to detect enemy aircraft.(Photo source: Rare).

The amplifiers of loudspeakers locate the huge sound of the Japanese fascist.(Photo source: Rare).

Another more compact aircraft detection system of Japan.(Photo source: Rare)

The US Navy Air Force aircraft detection system in 1925. (Photo source: Rare).

In the UK, in the 30s of the last century, the 4-speaker amplifier system was very popular.(Photo source: Rare).

In 1939, Germany developed an audio amplification system that detected the aircraft and still used it when World War II began.(Photo source: Rare).

By the 1940s, the radar system was born.At that time, with the old equipment, just listening to the soldier was able to detect enemy aircraft at maximum distance of up to 15 km, the maximum error was only about 2 degrees, even detected What kind of plane, how many aircraft.(Photo source: Rare).

The sound locator is used by the Swedish army in 1940. (Photo source: Rare).