On
this date in 1935, Radar was tested in Orfordness, Suffolk, the first time radio-based detection and ranging was shown in
Britain. The first target that was detected: a flying boat 17 miles
(27 km) away. 10 things you might not know about radar.

The
word radar is an acronym for "radio detection and ranging"
which was coined in the early second world war.
Radar
uses Radio waves to determine if something, like a ship, Submarine or aircraft, is out there when you wouldn’t be able to see it, how
far away it is and how fast it is moving.
It
does this by sending out short bursts of radio waves, or pulses.
Some of these will bounce back if they hit something. The waves
which bounce back are known as echoes. By measuring the time it
takes for a pulse to leave the radar and return as an echo, the
system can calculate the distance to the object. If the object is
moving, the frequency of the returning waves changes slightly, which
helps the radar figure out its speed. This is called the Doppler
effect, which is the reason why a siren from an ambulance sounds
slightly different when it’s moving away from you rather than
coming towards you. Radar is similar to the echolocation that Bats use.
Physicists
knew about the concept of radar as far back as 1886 when Heinrich Hertz proved that electromagnetic waves (like radio waves) exist,
and that they could travel through different materials and bounce
off metal surfaces.
In
the early 1900s, a German inventor named Christian Hülsmeyer
created the telemobiloscope, a device which could detect ships in Fog up to 3km away. While it did help prevent collisions in poor
visibility, it didn’t tell you exactly where the other ship was.
Radar
technology grew very fast during World War II. Eight countries were
secretly working on developing it: the United Kingdom, Germany, the
United States, the USSR, Japan, the Netherlands, France, and Italy.
Some
historians believe it was radar, not the atomic bomb, which helped
the Allies win the war.
After
the war, other uses for radar were developed besides finding things
to shoot at. It’s used for navigation and making air and sea
travel safer; it’s also used in weather forecasting, tracking
animals and Birds and in medicine. The flapping of a bird’s wings
distinguishes it from aircraft, and it’s even possible to tell one
type of bird from another using radar.
Police
use radar guns to measure the speed of cars on the road. One person
who was caught and fined using one of these devices was Sir Robert
Watson-Watt, who was one of the people who developed radar in the
early days of the war with the aim of collaborating with the United
States to beat the German military.
The
cathode-ray tube has been the preferred technology for displaying
radar information ever since the early days. Radar displays have
developed alongside computer and television screens so they keep
getting better.
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