Radio waves are easy to generate, can travel long distances and can penetrate buildings easily, so they are widely used for communication, both indoors and outdoors. These waves also work in heavy wooden terrain, can cross glass walls and even work well in the moving vehicles.
Wavelength is a criterion to differentiate radio waves from other kinds of electromagnetic waves. In the electromagnetic spectrum, the radio waves come at the top if we talk about the wave length. Radio waves also are omni directional, means that they can travel in all directions from the source, so the transmitter and the receiver do not have to be carefully aligned physically.
The properties of radio waves are frequency dependent. At low frequencies, radio waves pass through obstacles like wall and glasses well, but the power falls off sharply with distance from source. At high frequencies, radio waves tend to travel in straight lines and bounce off obstacles. They are also absorbed by the rain. At all frequencies, radio waves are subject to interference from motors and other electrical and electronic equipments.
Due to radio's ability to travel long distances, interference between users is a problem. For this reason all government tightly license the use of radio transmitter. In the very low frequency, low frequency and medium frequency bands, radio waves follow the ground. These waves can be detected for perhaps thousand kilometers at the lower frequencies, less at the higher ones.
Amplitude Modulation broadcasting uses the medium frequency band, radio waves in this band pass through the buildings easily, which is why portable radios work indoors. The main problem using these bands for data communication is their low band width.
In the high frequency and ultra high frequency, ground waves tend to be absorbed by the earth. However, the waves that reach the ionosphere, a layer of charged particles circling the earth, are refracted by it and sent back to the earth. Under certain conditions, the signals can bounce several times.
There are various factors on which the traveling length of signal depends like frequency of the station, what is the power of transmitter, conductivity of soil antenna and the refraction through ionosphere. Above the earth's atmosphere there is a layer which have heavily charged ion molecules is called ionosphere. Refraction through ionosphere is a very big issue and is most worked on.
Radio operators use these bands for communication both for military and civil purposes. Along with communication data is also transferred that is in coded form. Now a day radio is also a very good means of entertainment. Thousands of channels are there which provide us news, music, weather forecast, traffic updates, house keeping tips, government announcements, sports commentary etc.
Tymon Hytem has worked in the electronics feild for the past 15 years. He enjoys helping people decide on electronic gadgets from telephones to <a href="http://www.satellitesounds.com/"> XM Radio </a> and choosing the perfect <a href= "http://www.satellitesounds.com/index.php?categoryID=81">XM Satellite Radio </a> system for their needs.
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