Radio Waves

Introduction

Radio waves are Generally a type of electromagnetic radiation with the longest wavelengths in the electromagnetic spectrum, with a frequency of 300 gigahertz (GHz) and below. At 300 GHz, the corresponding wavelength is 1 mm (shorter than rice grains); at 30 Hz the corresponding wavelength is 10,000 km (longer than the radius of the Earth). Like all electromagnetic waves, radio waves in a vacuum travel at the speed of light, and in the Earth’s atmosphere slightly lowers its speed. Radio waves are produced by charged particles, such as time-varying electric currents.

Heinrich Hertz demonstrated the presence of radio waves in 1880. Hertz demonstrated that radio waves had all of the qualities of electromagnetic waves in his experiment. In the electromagnetic spectrum, radio waves have the longest wavelength.

The radio wave is the fundamental component of radio communication. We can listen to our favourite music by tuning a radio to a specific frequency or wavelength. The radio picks up radio waves and turns them into mechanical vibrations in the speaker, which produces the sound we hear.

Properties of Radio Waves

Radio waves and numerous different properties. They are as follows:

• Electromagnetic waves are a type of radiation that includes radio waves. Radio waves have a longer wavelength than infrared light.
• Radio waves can easily travel very long distances.
• Just like other electromagnetic waves, Radio waves are also invisible and cannot be felt.
• In a vacuum, Radio waves travel at the speed of light. The speed at which they pass through the materials varies based on the object’s permeability and permittivity.
• Lightning and celestial objects with a fluctuating magnetic field naturally generate radio waves. Variable electric currents also contribute to their formation.
• Radio waves also exhibit properties like reflection, refraction, absorption and polarisation.
• Both electric and magnetic fields are present in radio waves.

Bands of Radio Waves

The different bands of radio waves are mentioned in the table below:

Wavelength and frequency of Radio Waves

While passing through an object, radio waves travel at a similar speed to light and are slowed down based on the item’s permittivity and permeability. The distance between one peak of the wave’s electric field and the next is measured in wavelength, which is inversely proportional to the wave’s frequency.

Radio waves have wavelengths ranging from thousands of meters to 30 cm. These relate to frequencies ranging from 3 Hz to 1 gigahertz (109 Hz).

Types of Radio Waves 

The different types of Radio Waves are as follows:

Low to Medium Frequency Range of Radio Waves: Extremely Low Frequency radio waves, the lowest of all radio frequencies, have a great range and are useful for communicating with submarines, as well as inside mines and tunnels. Lightning is the most prevalent source of Extremely Low Frequency/Very Low Frequency waves. Marine and aircraft radio are included in the Low Frequency and Medium Frequency radio categories, just as commercial AM radio is. The frequencies of AM radio recurrence groups range from 535 kHz to 1.7 megahertz. 

The Higher Frequency Range of Radio Waves: The radio wavelengths High Frequency, Very High Frequency, and Ultra High Frequency are used in FM radio, TV sound, public radio, cellphones, and GPS. These organisations usually employ “frequency modulation” (FM) to encode or overlay a sound or information signal onto the transporter wave.

As ecological components have no effect on the recurrence of how they influence adequacy, FM produces superior signal quality over AM. Variations in amplitude are ignored by the receiver.

The Shortwave Frequency Range of Radio Waves: Short radio waves operate in the High Frequency band, with frequencies ranging from around 1.7 megahertz to 30 megahertz. The shortwave range is divided into a few parts within that range, some of which are assigned to conventional telecom stations.

The Highest Frequency Range of Radio Waves: Super High Frequency and Extremely High Frequency refer to the highest frequencies in the radio band, and are sometimes mistaken for microwave frequencies. Molecules that can be seen all over will absorb these frequencies, limiting their range and applicability.

Radio communication

To receive radio waves from AM or FM radio stations, a radio antenna is used. This antenna picks up a lot of radio frequencies, so you’ll need a radio tuner to tune in to a specific frequency. All of this can be accomplished using a resonator, also known as an inductor, a circuit containing a capacitor, or a crystal oscillator. The resonator is set to resonate at a frequency that permits the tuner to amplify sine waves at a certain radio frequency while avoiding other sine waves.

Uses of Radio Waves 

The primary goal of radio is to transmit information from one location to another without the use of cables by using the intervening media (i.e., air, space, and nonconducting materials). Radio is used for transmitting data in coded form in addition to transmitting sound and television signals. It is also used to send out signals and pick up their reflections from objects along their path in the form of radar. Long-range radio waves allow astronauts on the moon to connect with Earth and transport data from space probes as they go to other planets. Radio range, radio compass (or direction finder), and radio time signals are generally utilized for ship and aircraft navigation.

Special receivers can use radio signals from global positioning satellites to provide an accurate indication of position (see navigation satellite). Both satellite and terrestrial digital radio offer better audio clarity and volume. Radio signals trigger a variety of remote-control equipment, including rocket and artificial satellite operating systems, as well as automatic valves in pipelines. Portable transmitters and receivers were developed as a result of the invention of the transistor and other microelectronic devices.

Radio transceivers are what cellular and cordless telephones are. Many telephone conversations are frequently routed through radio rather than wires, and others are sent to relay satellites via radio. Some astronomical planets and interstellar gases emit strong radio waves, which can be viewed with radio telescopes equipped with highly sensitive receivers and huge directional antennas.

Conclusion

In this article we have studied about Radio waves. Generally Radio waves are produced by transmitters and received by radio receivers, using antennas. Radio waves are widely used in modern technology for mobile radio communication, broadcast, radar and radio navigation systems, satellite communications, wireless computer networks and many other applications. Different frequencies of radio waves have different propagation characteristics in Earth’s atmosphere; long waves can diffract around obstacle like mountain and follow the contour of the earth (ground waves), short waves can reflect off the ionosphere and return to the earth beyond the horizon (skywaves), while very short wavelength bend or diffract very slightly and travel on the line of sight, so their propagation distances are limited to the visible area.