Radio waves are the electromagnetic radiations that lie within the frequency range of 3 kilohertz to 300 gigahertz. The wavelength of the radio waves lies between 1 millimetre to several hundred meters. Out of all the electromagnetic waves, radio waves have the longest wavelength and lowest frequency. Radio waves travel at the speed of light and can penetrate through rigid surfaces with great ease.
Examples of Radio Waves
1. Radio Broadcasting
One of the prime applications of radio waves is radio broadcasting. Here, first of all, the sound signal is modulated with the help of various modulation techniques such as amplitude modulation (AM) and frequency modulation (FM). The modulated signal is then encoded, and transmitted in the air with the help of radio transmitters. On the receiver side, the signal can be retrieved by simply tuning the receiver to the same frequency as that of the transmitter.
2. Cellular Networks
The radio waves are capable of penetrating through rigid materials and obstacles such as buildings and trees with great ease. This property of the radio waves is utilized by the communication industry to establish cellular links for the purpose of information exchange. The radio transmitter and radio receiver installed in the internal circuitry of the cellphone helps in the transmission and reception of a signal with the help of radio waves.
RADAR is the acronym for radio detection and ranging. As the name suggests, a RADAR makes use of radio waves to detect the presence and position of an obstacle. The transmitting antenna of the RADAR sends the radio waves into the environment. These transmitted waves travel through the air and bounce back after striking an obstacle. The reflected waves then get collected by the radio receiver. The speed with which the wave travels is already known, and the time taken by the wave to return is noted. Hence, the position of the obstacle can be determined easily.
4. Radio Astronomy
As the name suggests, radio astronomy makes use of radio waves to get a better and clear view of the planets, comets, asteroids, and other celestial objects. These radiations do not get affected by adverse weather conditions such as rain, fog, sunlight, etc. This property of the radio waves is utilized by the radio astronomer to study the composition, location, motion, and other related properties of the celestial bodies with great ease.
5. Satellite Communication
Radio waves are used to broadcast information over significantly large distances with the help of satellites. The radio wave antennas present on the earth are used to transmit signals to the satellite. The satellite then sends the received signal back to the earth station. This signal is then processed, and the information is extracted. Television broadcasting is one of the best applications of radio waves in satellite communication.
6. Radio Telemetry
Radio waves are often used in radio telemetry to locate the exact position of an animal and to track its movement. This is done by attaching a radio transmitter to the body of the animal. The transmitter constantly radiates radio waves in the environment. The radiations emitted by the transmitter are then collected by the receiver, and the result gets displayed on the screen.
7. Remote Controlled Toys
Most of the remote-controlled toys work on the basis of radio waves. The radio receiver suspended in the internal mechanism of the toy responds to the radio waves transmitted by the radio transmitter present in the controller. Hence, the radio waves allow the user to operate the toy from a distance.
8. Navigation and Air Traffic Control
One of the major applications of radio waves lies in establishing a reliable communication network between the aeroplane and air traffic control unit. Very high frequency or VHF radio waves are generally used for this purpose. Radio waves are also used to maintain the air-to-air connection between the aircrafts.
9. Magnetic Resonance Imaging
Radio waves are widely used in the medical domain. For instance, radio waves are used in magnetic resonance imaging machines to obtain a detailed and clear 3-dimensional view of the internal organs of the patient. Using radio waves to perform the MRI scan or in other medical applications is advantageous because they do not cause any adverse side effects.
The communication systems used by the submarines make use of the radio waves for the easy exchange of information. Typically, extremely low-frequency or ELF radio waves are used for this purpose. This is because these radiations do not get absorbed by the seawater very easily.