InterviewSolution
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Derive an expression for covering range of TV transmission Tower. |
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Answer» For large TV coverage, the transmission of TV signal is done from a tall antenna.Consider a TV antenna OP of heighth. The transmitting signals cannot be received beyond points R1and R2. This is due to curvature of earth.Clearly, OR1and OR2are the maximum distances, from the antenna, upto which the transmission signal can be received.Let OR1= OR2= d [d is half the total range]The relation between heighthof the TV antenna and the maximum distancedupto which the TV signal can be received can be derived on the basis of geometrical considerations.From right – angled triangle CR2P, CP2= CR22+ PR22…. (1)In right – angled triangle POR2, PR22= h2+ d2[Note that ∠POR2can be taken as right angle]Also, CR2= CO = R and CP = R + hFrom Equation (1) (R + h)2= R2+ (h2+ d2) R2+ h2+ 2Rh = R2+ h2+ d2ord=2Rh−−−−√It is clear from this equation that if h is large, d will be large. This explains as to why the television broadcasts are made from tall antennas. |
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