In planning a telecommunication system with using radio waves so that the most fundamental and is important to be loss-loss that occurred in the air open, a wave that pass from electromagnetic antenna transmitter (Tx) antenna to the receiver (Rx) or vice versa will decreased power caused by the layer of space empty and the oxygen in the atmosphere such as oxygen, water vapor, clouds, fog and rain. Large decrease in power that occurred influenced by the distance adopted, or astringent substances-particles in the open air and the air itself.
From oxygen in the atmosphere, rain is a attenuation factor which causes the most dominant. Problems propagation in millimeter wave communication system that operates in the high frequency attenuation GHz is caused by the rain. The influence of rain attenuation against propagation radio waves start become significant at frequencies ≥ 10 GHz. The higher frequency, the greater attenuation rainfall experienced. Of course this technology for applications in tropical countries such as Indonesia, rain attenuation which is a function of the size distribution of point rain will be essential given the problems that the tropics have high rainfall
To be able to understand the process and the amount of interference radio waves by rain, need to know the nature and condition atmosphere and the parameters that affect the rain attenuation occurrence, such as the size of point rainfall, point rain rate, rainfall rain and the length of the track waves through the region rain. The attenuation amount of rain on a certain trajectory determined by the nature micro physic (dielectric nature and composition, temperature, shape, size distribution, orientation) and macro physic (profile variations in nature micro physic in different types of rainfall and climate) from the rain.
Rainfall, water like Hamburger from Sky
Water, and all the other molecules in the nature, have particularity. Changes small on the nature of water that has been perfect in every detail this will impact damage for life. Let us see only one of them, namely the form of drops of rain water. Contrary to the understandinggeneral, grain is not water down the rain-like droplets in the form of tear or similar form of salak fruit. Fact, rain water droplets rounded shape at just fall out of cloud. For grain rain water is small, rounded form of this last. However, for larger grain, the falling down, change shape and
more like half a ball flat. In English visibility called this regular hamburger-bun shape or form of bread burger: flat on the surface beneath and around the surface top (see picture). Changes in the form of this style of press due to the air on the bottom surface of the water droplets that are rain to fall earth. Style press the opposite direction with the rainfall average beneath the surface of the water droplets rain. This form is zoom in zoom out so that resistor style speed falls rain water. The low-speed falls to the ground to avoid severe damage due to collision rainwater.
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