We can view objects in the world around us because the light (usually from the sun) is reflected in our eyes. If you desire to walk at night, you can light a torch to see where you are going.
A beam of light comes midst the torch, bounces off the object before you, and bounces off your eyes. Your brain immediately calculates what this means: it tells you the distance from objects and prevents your body from moving.
The radar works the same way. The word “radar” means the detection and range of radio, which gives a pretty big inkling as to what it does and how it works. Imagine an airplane flying in thick fog at night. Pilots can’t see where they’re going, so radar is helping them.
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How Does Radar Use Radio?
Whether you’re flying an airplane, a ship, or something else, a radar set needs the same set of necessary components: something to generate radio waves, something to send into space, something to receive and something to receive display information. So the radar operator can understand it quickly.
A team produces the radio waves used by the radar called the magnetron. Radio waves are homogeneous to light waves: they travel at the same speed, but their waves are quite long and have much lower frequencies.
Light waves have a wavelength of about 500 nanometers (500 billion lunar meters, which is approximately 100-200 times thinner than a human hair).
In contrast, the radio waves used by radar generally vary by a few centimeters to one meter, the length of your fingers to the width of your hand, or about a million times longer than light waves.
Light and radio waves are a portion of the electromagnetic spectrum, which means that they are manufactured with fluctuating electrical and magnetic energy flowing through the air.
The waves produced by a magnetron are like microwave ovens, similar to those created by a microwave oven. The difference is that the magnetron on the radar has to send waves over several kilometers, not just a few centimeters, which makes it much bigger and more durable.
What is the Radar used for?
Radar is even better known as military technology. Radar antennas mounted at airports or other ground stations, for example, can be used to detect enemy aircraft or missiles.
The United States has developed a first ballistic missile alert system (BMEWS) to detect incoming missiles, with three major radar detection stations in Clear, Alaska, Thule in Greenland, and Fylingdales Moor in England.
However, radar does not only use the military. Most civil aircraft and larger ships and vessels now have radar as an aid to general navigation.
Each major airport has a large radar antenna to help air traffic controllers direct planes in and out, regardless of weather conditions. The next time you go to the airport, look for a rotating radar plate placed on or near the control tower.
You may have seen cops using roadside radar guns to detect people driving too fast. It is based on a slightly different technology called Doppler radar. You’ve probably noticed how the fire truck siren seems to crash into the driveway.
When the motor moves towards you, the sound waves from your siren are effectively repelled at a shorter distance, so that they have a shorter wavelength and a higher frequency, which we hear as a higher tone.
When the motor moves away from you, it works in the opposite direction: it makes the sound waves longer, a lower frequency, and a lower tilt.
Then you hear a noticeable drop in the siren tone by the time this happens. This is called the Doppler effect. The same science works on a radar gun. When a police officer shoots a speed camera on your car, the metal body reflects the beam backward.
The faster your car moves, the more the radio waves’ frequency in the beam changes. The sensitive electronic equipment of the radar gun uses this information to calculate the speed of your car.
Radar has many scientific purposes. Doppler radar is also used to predict whether to determine the speed of storms and when they are likely to arrive in certain cities.
Meteorologists launch radar beams into the clouds and use reflected rays to measure the rate of rain and its speed of fall. Scientists use a form of visible radar called lidar (light and distance detection) to measure air pollution by laser.
Archaeologists and geologists direct radar to Earth to study the composition of the Earth and find buried sites of historical interest.
Point radar is not used to assist submarines when they are underwater. Electromagnetic waves don’t travel easily through dense seawater (so the deep ocean is deep.
Instead, the submarines use a very similar system called SONAR (Sound Navigation And Ranging), which uses the sound for “looking at” objects instead of radio waves.
However, submarines have radar systems that they can use when moving on the surface of the ocean (such as entering and leaving a port).
Countermeasures: how to avoid radar?
Radar is extremely effective at detecting enemy planes and ships, so much so that military scientists have evolved in one way or another! If you have an excellent radar system, it probably also has your enemy.
If you can see his planes, he can also see yours. So it would be best if you had planes that can somehow “hide” inside the enemy radar without being seen. Stealth technology was created for this.
You may have seen the infamous B2 Air Force concealed bomber. Its crisp, angular lines and metallic windows are designed to scatter or absorb radio waves’ rays so that enemy radar operators cannot detect them.
An invisible plane is so efficient that it appears on a radar screen without more energy than a little bird!