Radio waves are arguably the backbone of modern technology because they play a fundamental role in transmitting data, audio, and images.
If you have ever tuned your radio to a certain frequency to listen to the news or your favorite music, then you have experienced the magic of radio waves.
Radio waves and microwaves, collectively known as radio frequency (RF) energy or radiation, are electromagnetic energy emitted by transmitting antennas.
The transmitter does not only emit RF signals but also modulates it. A receiver reverses this process and demodulates the signal.
A typical RF system consists of transmitters, antennae, amplifiers, filters, cables, and power sources. The system transmits and receives wireless signals using radio waves. During transmission, RF Cable Assemblies are used to ensure minimal signal loss and interference.
Depending on the frequency, radio waves are used for broadcasting (FM and AM radio), military communications, wireless computer networks (Wi-Fi and WLAN), navigation, and mobile phones, among others.
What are radio waves?
Radio waves are a type of electromagnetic radiation, just like visible light, microwave, ultraviolet (UV), and X-rays. They are all part of the electromagnetic spectrum. However, radio waves have the longest wavelengths in the spectrum and lower frequencies than microwaves.
Electromagnetic radiation has both electric and magnetic energy fields traveling through space in the form of waves.
The existence of radio waves was first proven by Heinrich Hertz in the 1880s. It can pass through the air, water, and even some solid objects, making them useful for communication. They can be modified to carry information, like music, voice, image, or data.
Common applications of radio waves
Radio waves are directly or indirectly used in our everyday lives. Some of its applications can be found in:
- Radio
- Television
- Wi-Fi
- Bluetooth
- Cell phones
- Remote controls
- Garage door openers
- Wireless sensors
- Global Positioning System (GPS)
- Radar
How do radio waves transmit information?
To transfer information using radio waves, you need carrier waves and a receiver.
Radio waves transmit information through a process called modulation. Modulation involves changing the properties of a carrier wave such as amplitude or frequency to encode information like sound, image, video, or data so that it can be transmitted through the airwaves and received by a radio receiver.
Generally, waves have two basic properties―amplitude and frequency. Amplitude refers to the height of the wave while frequency is a measure of how close the waves are to each other.
When transmitting information with radio waves, there are two major types of modulation used: amplitude modulation (AM) and frequency modulation (FM).
To transmit information using AM, the amplitude of the carrier wave is varied in proportion to the amplitude of the information signal. The carrier frequency usually remains constant during AM.
On the other hand, transmitting information using FM involves varying the frequency of the carrier waves in proportion to the amplitude of the information signal.
Although it is possible to transmit information without modulating the carrier waves, however, it will require a lot of amplification as you will be using a very low frequency. The resources needed will also be more than typical, hence a higher cost and energy consumption.
Once modulated, the carrier wave is amplified and fed to a transmitting antenna which radiates the radio waves into the air.
The receiver’s antenna will then receive the waves after which a process called demodulation is executed. During demodulation, the receiver circuitry extracts the original signal from the modulated carrier wave using techniques similar to the modulation method used at the transmitter, except this time, the result is reversed.
The demodulated data is then processed and used by the receiving device.
Factors affecting radio wave transmission and reception
The speed of radio waves transmission is determined by the permeability and permittivity of the material medium in which they are transmitted.
When in a closed vacuum radio waves can travel at the speed of light, but in air, they travel slightly slower due to the interactions with air molecules. The waves are slower when traveling in an aquatic environment.
A study that observed the effects of water conductivity on the detection distance of radio wave transmission discovered it increases with decreased water conductivity. For context, detection distance is the maximum distance from which a receiver can identify a transmitted radio signal.
Aside from the material medium, other factors like frequency, bandwidth, signal strength, modulation, and interference can affect the transmission and reception of radio waves. For instance, radio waves with higher frequencies can carry more data but have a shorter range.
Other radio waves or obstacles can interfere with the signal thereby making communication difficult or impossible. AM receivers are more susceptible to interference than FM receivers. Meanwhile, RF cable assemblies can help reduce interference.
