Each and every phenomenon in this world is governed by laws. Everything that exists emits certain energy in its energy field and has a certain wavelength. Range of electromagnetic spectrum exists including various types of electromagnetic radiation like ultraviolet rays, microwaves and others. These waves differ based on frequency and energy. The waves with the least energy and longest wavelength are called radio waves. Although these waves might not be visible ordinarily yet, they play a significant role in information transmission.
Nature of Radio Waves
Clerk Maxwell and Heinrich Hertz are usually crowned for the discovery of radio waves. Radio waves are emitted through space and use wireless communication. With the defining feature of not being absorbed and relatively least energy, radio waves are invisible to the naked eye. These waves have different frequencies ranging from low bandwidth which is less than 3 MHZ to extremely high frequency range from 30 to 300 gigahertz (GHz). There are still other frequency ranges with corresponding wavelengths between these two extreme ranges. Bandwidth range differs according to the information sending and receiving bodies.
Radio waves travel in a straight line. After being generated from the source, they travel through the sending antenna towards the receiving medium. These waves travel in the form of electric pulses and after reaching the receiving end. Here, again the signals are converted into sound. Thus, information passed on from source becomes audible and can be heard at the receiving end.
Types of Radio Broadcasting
Radio waves can be classified into two major types depending upon the frequency range and nature of the receiving medium. Commonly known as FM and AM, these radio waves are used for data transmission over radio sets, television , phone and other devices using electromagnetic waves to travel and communicate across the globe.
Amplitude Modulation (AM)
Abbreviated as AM, Amplitude Modulation is one of the divisions of radio wave transmission. The information travels through the medium within a frequency range of 540-1600 kilohertz (KHz). The amplitude of the input is modified to make it audible for the receiver keeping frequency constant.
Frequency Modulation (FM)
FM is yet another classification of radio broadcasting. Frequency Modulation refers to the process of sending information by modulation in the frequency to make sound audible. It is the type of commercial transmission within a frequency range of 88 to 108 Megahertz (MHz). Unlike AM, amplitude remains constant whereas frequency of the input changes during data transmission.
Radio Wave Propagation
Radio wave propagation differs based on the type of source sending the signal and transmitter sending it to the final destination. Major classifications might include
Ground wave propagation
These waves travel over earth’s surface within the medium and low frequency range. All other frequency waves are blocked and refracted. TV and radio uses this kind of radio propagation.
Free space propagation
Signals are transmitted from the source in space via cables or optical fibre.
The radio waves are scattered beyond earth’s surface or over the horizon.
Propagation of radio waves over 30 MHz depends upon weather conditions and is therefore called tropospheric propagation.
Radio waves are reflected or refracted towards earth from electrically charged ions in the atmosphere.
Radio waves are useful in transmitting information over different frequency ranges over the globe. Radars and navigation systems also make use of radio waves to detect direction and any possible threat. Media transmissions and cellular communication is also possible through radio transmission. Moreover, radio waves also serve as important tools in the medical field. Magnetic Resonance Imaging (MRIs), X Rays and other such diagnostic procedures can be possible only using radio waves.
Besides application of radio waves, there are certain hazardous effects of radio waves too. Long Term exposure to radio waves might cause medical issues ranging from mild to severe. Skin burn, cancer and damage to body tissues are most common among other medical problems caused by radio waves. Besides humans, radio waves are equally harmful for the environment. Increased radioactive waves and absorption of these waves producing damages to wires and heating other objects disrupting lives of living and non-living organisms.