Radio waves work by sending invisible waves, transmitting information such as TV, internet and music that are picked up receivers and turned into the different types of media.
Radios have two parts, the transmitter that takes data (sound) and encodes it into ‘Sine’ waves. The second is the antennas, which are the wires / conductors that receive electromagnetic waves. The information data is encoded into the pattern of the wave, like a language that you speak.
However the antenna will pick up thousands of radio signals at a time, a radio tuner is necessary to tune in to a particular frequency
There a number of other technologies that use radio to waves to work, a few examples being Wireless connections, Television mobile phones and even in medicine!
Radio waves can be transmitted over thousands of miles by following the curvature of the earths surface, skywards or space wave, a very high or ultra high frequency wave or a microwave.
The most common radio frequency bands are AM/FM and Television stations.
A transmitter or radio transmitter is an electronic device which, with the aid of an antenna, produces radio waves. The transmitter generates a radio frequency AC current which is applied to the antenna. When the antenna is ‘excited’ by the AC current it radiates radio waves.
Audio Signals are generally transmitted using a cable but a lot of them require what is called a carrier wave. A carrier wave transmits information through space as an electromagnetic wave used in radio communication. A modulator signal from a source is added to the carrier then the modulated signals are sent along a channel via a cable or radio waves.
In FM transmission, when the source is transmitted (from a microphone) the frequency of the sound waves can be added or subtracted in a proportion from the set FM transmission frequency. The wave amplitude is determined by the amplitude of the sound waves.
Am transmission is the opposite, the amplitude of the AM waves is determined by the frequency of the sound waves and the frequency of the AM waves is determined by the amplitude of the sound waves.
Radio Waves – Visible waves that carry data such as pictures and sound.
Microwaves – Microwaves are used to transmit signals for mobile phone calls. The transmitters and receivers on buildings communicate with mobile phones that are in range.
Infrared – These are normally used for military operations, such as surveillance, tracking and night vision but can be used in civilian life for things like wireless communication, remotes and controls and radio forecasting.
Ultraviolet – Found in sunlight and is also visible and can be used to change skin colour (also knows as tanning) which carries health risks such as cancer.
X-ray – Used for looking at the internal make up of things such as the human body and bags at the airport.
Gamma Ray – Gamma rays can be used for sterilising food and medical items and treatment of certain cancers
Aerials pick up (or Radiate) radio waves and convert them into what you see/hear. There are two common aerials that are used in modern technology;
The Dipole aerial and the Parabolic dish aerial. The Dipole aerial consists of two vertical (Or less commonly horizontal) pieces of metal that conduct the radio waves. Dipole aerials are used for television signals and high frequency radio signals.
The Parabolic dish aerial (the big circular dishes, on houses or space stations). The radio waves are conducted by a small dipole in the dish and sent through the transmitter. The radiation patterns used by these aerials makes them very good for line of sigh communication.
Radio waves are extremely important and have made many, many things possible and without them we would not be able to of made as much progress as we have in technology, not just in our personal lives but professional and even in wars (UAV’s, Communication, Radar and calling airstrikes!) Most of us use radio waves every day, they make communication possible whether it be a friend in the same road or someone on the other side of the world!
Landline Phones – Phones work by sending signals down a wire, the microphone changes sound waves into electrical signals and the speaker changes the signals into waves.
Mobile Phone – Mobiles use cells. Cells are radio frequency that are used in the local area, each one has its own frequency and the cells adjacent to it has different frequencies and they each contain as base station transmitter or receiver.
Television – TV signals are transmitted by using a transmitter what sends the information to a receiving aerial and turner by radio waves, using ultra high frequency. To receive signal it needs to be captured by a satellite dish, (A satellite dish is an antenna but its designed to focus on a specific source) the information is sent to the dish via satellite dish using radio waves and received by a part of the dish called the ‘feed horn’.