InterviewSolution
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InterviewSolution
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If the sum of the heights of transmitting and receiving antennas in line of sight of communication is fixed at h, show that the range is maximum when the two antennas have a height `h//2` each.A. `h//2`B. 2hC. hD. 4h |
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Answer» Correct Answer - A The range of line-of-sight communication between two antennas is given by `v=sqrt(2Rh_(T))+sqrt(2Rh_(R))` Given `h_(T)+h_(R)=h` and let `h_(T)=H`, then `h_(R)=h-H` `therefore r=sqrt(2R)[sqrt(H)+sqrt(h-H)]` For r to be maximum, `(dr)/(dH)=sqrt(2R)[(1)/(2sqrt(H))+(1)/(2sqrt(h-H)(-1))]=0` or `(1)/(2sqrt(H))-(1)/(2sqrt(h-H))=0` or `H=h-H` or `H=(h)/(2)` |
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