- an overview of radio and wireless technology and some of the major radio adn wireless applications.
Radio is very widely used in everyday life now, and it is becoming more widely used as new applications are being found all the time. One of the original terms for radio was wireless, end even today many people refer to a radio as a wireless set. However the term describes this form of communication very well because it is a form of wire-less communication. Now this term is coming back into use because radio or wireless applications are becoming more widespread. Nowadays the term is being used to describe short range applications that might have used a wired connections not long ago. With these and many other applications, radio, or wireless technology is very widely used, and will continue to become more so as time progresses because of the flexibility it provides.
The story of radio dates back to some of the early discoveries into electrical science. It could be said these were started by the ancient Chinese and Greeks.
Major radio applications
Radio technology is used in a wide number of applications, and the list is growing all the time. Some of the earliest applications were to enable communications where wired links were not possible. Marconi, one of the early pioneers saw a need for radio communications between ships and the shore, and of course radio is still used for this today. However as radio became more established people started to use the medium for broadcasting. Today a huge number of stations broadcast both sound and vision using radio to deliver the programmes to the listener.
There are many more applications for radio. Apart from being used for ship to shore communications, radio is used for other forms of communications. Short wave radio was one of the first applications for radio. With ships sailing over vast distances it was seen that radio could provide a means for them to communicate when they were in the middle of an ocean. By "bouncing" the signals off reflecting layers in the upper atmosphere, great distances could be achieved. Once it was sent hat this could be done, many others also started to use the short wave bands were long distance communications could be made. It was used by everyone from the military to news agencies, weather stations, and even radio hams.
Radio is also used for telecommunications links. Signals with frequencies in the microwave region are normally used. These signals have frequencies much higher than those in the short wave band and they are not affected by the ionosphere. However they provide reliable direct line of sight links that are able to carry many telephone conversations or other forms of traffic. However as they are only line of sight, they require towers on which to mount the antennas to enable them to transmit over sufficiently long distances.
Satellites are also used for radio communication. As short wave communications are unreliable, and cannot carry the level of traffic required, higher frequencies must be used. It is possible to transmit signals up to satellites in outer space. These can receive the signals and broadcast them back down to Earth. Using this concept it is possible to transmit signals over vast distances, such as over the oceans. Additionally it is possible to use the satellites for broadcasting. Transmitting a signal up to the satellite, it is then relayed on a different frequency, and can give coverage over a whole country using just one satellite. A land based system may require many transmitters to cover the whole country.
Satellites may also be used for many other applications. One of these is for observation. Weather satellites, for example, take images of the Earth and relay them back to Earth using radio signals. Another application for satellites is for navigation. GPS, the Global Positioning System uses a number of satellites in orbit around the Earth to provide very accurate positioning. Now further systems including Galileo (a European based system) and Glonass (a Russian based system) are being planned and put into operation.
Radar is an application of radio technology that has proved to be very useful. It was first used by the British in the Second World War (1939 - 1945) to detect incoming enemy bombers. By knowing where they were, it was possible to send up fighters to intercept them and thereby gain a significant advantage. The system operates by sending out a short burst of wireless energy. The signal is sent out and reflects back from the objects in the area that is 'illuminated' by the radio signal. By knowing the angle at which the signal is returned, and the time it takes for the reflection to be received, it is possible to pinpoint the object that reflected the signal.
In recent years there has been an explosion in personal communications. One of the first major applications was the mobile phone. Since their introduction in the last 20 years of the 20th century, their use has mushroomed. Their growth has shown the value of mobile communications and mobile connectivity. Accordingly other applications such as Bluetooth, Wi-Fi and others been developed and are now part of the wireless scene.
With the growth in the requirement for mobile connectivity, it is certain that wireless technologies with radio at the core will continue to thrive and become more widespread. To meet the demand it is likely that new technologies will be developed to maximize the use of the available radio spectrum. It is also anticipated that the user will be less aware of the underlying technology. With the increasing complexity, it will be necessary that all the technicalities are handled by the software, leaving the user free to use the device, whatever it may be, easily and freely.