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一般来说,室外电视天线架得高,接收到的信号强,效果就好。由于电视频段的电波传播特性近似光的传播,且地球是呈圆形的(严格说略呈椭圆形),所以,电波传播时会受到地球弧面的影响,因此电视发射台与接收天线之间的距离就受到限制。例如:电视台发射天线高H_1,电视接收天线高H_2,而电视台的发射功率又足够强,那么,能收看电视节目的最远距离L可以这样推算出来(见图1)。已知地球半径R约为6390公里,则从图中可以看出:
In general, outdoor TV antenna rack is high, the signal received is strong, the effect is good. Since the electric wave propagation characteristics in the television frequency band approximate the propagation of light and the earth is circular (strictly speaking elliptical), the radio wave will be affected by the arc of the earth. Therefore, the distance between the TV transmitting station and the receiving antenna The distance is limited. For example, if the television station transmits antenna height H_1 and television receiving antenna H_2, and the transmitting power of the television station is strong enough, the farthest distance L from which the television program can be watched can be calculated as shown in FIG. 1. Given that the Earth’s radius, R, is about 6390 km, it can be seen from the figure that: