Propagation Catagories
Free Space Propagation; Here the radio signals travel in free space, or away from other objects which influence the way in which they travel. It is only the distance from the source which affects the way in which the field strength reduces. This type of radio propagation is encountered with signals travelling to and from satellights.
Ground Wave Propagation; When signals travel via the ground wave thay are modified by the ground or terrian over which they travel. They also tend to follow the earth's curvature. Signals heard on the medium wave band during the day use this form of propagation.
Ionospheric Propagation; Here the radio signals are modified and influenced by the action of the free electrons in upper reaches of the earth's atmosphere called the Ionosphere. This form of radio propagation is used by stations on the short wave bands for their signals to be heard around the globe.
Tropospheric Propagation; Here the signals are influenced by the variations of refractive index in the troposphere just above the earth's surface. Tropospheric radio propagation is often the means by which signals at VHF and above are heard over extended distances.
There are many radio propagation scenarios in real life. Often signals may travel by several means, signals travelling using one type of propagation interacting with another. However to build up an understanding of how a signal reaches a reciever, it is necessary to have a good understanding of all the possible methods. By understanding these, the interactions can be better understood.
Ground Wave Propagation; When signals travel via the ground wave thay are modified by the ground or terrian over which they travel. They also tend to follow the earth's curvature. Signals heard on the medium wave band during the day use this form of propagation.
Ionospheric Propagation; Here the radio signals are modified and influenced by the action of the free electrons in upper reaches of the earth's atmosphere called the Ionosphere. This form of radio propagation is used by stations on the short wave bands for their signals to be heard around the globe.
Tropospheric Propagation; Here the signals are influenced by the variations of refractive index in the troposphere just above the earth's surface. Tropospheric radio propagation is often the means by which signals at VHF and above are heard over extended distances.
There are many radio propagation scenarios in real life. Often signals may travel by several means, signals travelling using one type of propagation interacting with another. However to build up an understanding of how a signal reaches a reciever, it is necessary to have a good understanding of all the possible methods. By understanding these, the interactions can be better understood.
posted by World Radio Club at 11:58 AM
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