Microwave Links
A system utilizing a stream of radio waves between two points for communication purposes is called a microwave link if it makes use of the so called "microwave frequency range". Many systems used today use this way of communication and it is crucial to many important systems we use in hospitals, police stations and fire departments. But it does not stop there, as the application for commercial purposes are many. Think mobile phones and wireless networks to name but a few examples of commercial usage of microwaves today.
The main reason this type of communication is very popular is because it falls in the so called broadband category which makes these systems suitable to transfer large amounts of data from point to point at high speeds. It is a cost effective means of communication as no further equipment is required between the points. A sender and receiver unit will suffice. This often outperforms other types of connections when weighing costs against effectiveness. Microwave links are immune to weather conditions which make them applicable under almost all conditions.
A microwave link transmitter uses a signal that carries the information to the receiver. The type of information can be almost anything: speech, data, and television or radio programs. Even a combination of all of those is possible. This makes a microwave powered system one of the most flexible ones at our disposal.
The transmitter unit generates the required energy and produces the signal and modulates it in order to relay the data. A simple example of modulation would be using a flashlight to transmit Morse code using long and short flashes.
The second vital part in the process is the transmission line in order to carry the data from point A to point B, where point B is an antenna receiving the information. For this to work, coax cables called waveguides are used because regular cable interferes with the frequency of the microwaves.
Through the Antenna the signal is transmitted into the air where it is picked up by the receiver.
The type of Antenna that is used in microwave links are so called directional antennas enabling us to cover long distances but still using small amounts of energy. This makes the microwave systems very cost effective and less disrupting to our environment.
In order for microwave links to function properly the path to the receiver must be clear. This means the receiver must be placed in a high location where it will not be obstructed by buildings or geological structures. Seasonal disturbances must also be taken into account, like trees that are bare during winter but packed with leaves during the summer season. For this reason receiver units are often placed on high locations like towers.
At the receiver end, the data is extracted and processed to be used in its original form which is called demodulating. Demodulating is the process of separating the data from the microwave energy in order to be processed. The process as described here takes place at speeds that are very close to the speed of light. Therefore the transmission of data is almost instant even when long distances are concerned. Over the years microwave links have become the heart of our ways to communicate and will remain so for years to come.
