Wireless Technology This refers to a method of transmitting data or information from one point to another without any physical connection. Wireless technology came about from the human need to communicate at times across great distances quickly without much contact. In the past our forefathers practiced this by use of smoke signals and beating of drums.
However with the coming of technology age wireless communication went high tech and has become quite popular. To transmit information this technology relies a lot on antennas and receiving aerials. Media that uses wireless technology include microwaves, radiowaves and infrared frequencies.
Microwave transmission
Their frequencies range from 3GHz to 40GHz on the electromagnetic spectrum.Their small wavelength makes it possible to release their energy in water so they are used to to make domestic appliances e.g micro wave ovens. They are also ideal in point to point transmission which means that a signal is directed through a focused beam from a transmitter to the receiving station, this principle is especially applied in satellite communication.
Radio communication
Radio waves travel just like the surface water waves, which are omni directional. This means that they start from a central point and spread out in all directions. As they travel outwards their energy spreads outwards over the covered area. Radio waves are radiated in the atmosphere by radio frequency antennae at a constant velocity and received via receiving aerial or link .These waves can be high frequency, very high frequency or ultra high frequency.
High frequency radio waves (HF) are propagated by directing it to the earth’s ionosphere, which reflects it back to earth’s surface and the receiver picks the signal. Before the advent of satellite communication this was the commonly used method of communication across continents or on high seas. However this method carries a high risk of being intercepted by eavesdropping parties.
Very high frequency (VHF) radio waves are transmitted along the earth’s surface. Since its curved, the signal attenuates at the horizon .This means that a repeater station has to be placed strategically maintain a line of sight in order to receive, amplify and propagate the signal from one area to another. The technology is used in the hand held radio devices like walkie-talkie radios. Unlike the high frequency wave, its range is limited though its preferred if there’s no major obstructions on the landscape.
Ultra high frequencies (UHF) waves are very high frequencies waves when it comes to the line of sight principle; this means that there should be no barrier between the sending and receiving aerials. However the waves require smaller aerials as UHF can be made to to follow a narrower path unlike VHF.
Infrared transmission
These waves are just below the visible light on the electromagnetic spectrum. Just like radio waves they are invisible to the human eye. Communication through this medium is achieved by use of infrared transmitters and receivers. Receivers of infrared signals must be within a line of sight in the same room. This is because unlike radio signals, infrared waves cannot penetrate obstacles like walls; however they can be reflected off surfaces like wall or surfaces until they reach their destination.