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प्रश्न
Answer the following question.
Why a signal transmitted from a TV tower cannot be received beyond a certain distance? Write the expression for the optimum separation between the receiving and the transmitting antenna.
उत्तर
The signal transmitted from a TV tower cannot be received beyond a certain distance because of the curvature of the earth. The expression for the optimum separation between the receiving and transmitting antenna:
`d = sqrt(2hR)`
d: Optimum separation.
h: Height of the antenna
R - Radius of the curvature of Earth.
संबंधित प्रश्न
Due to economic reasons, only the upper sideband of an AM wave is transmitted, but at the receiving station, there is a facility for generating the carrier. Show that if a device is available which can multiply two signals, then it is possible to recover the modulating signal at the receiver station.
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I-V characteristics of four devices are shown in Figures.
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(i) | (ii) | (iii) | (iv) |
Identify devices that can be used for modulation.
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- the size of the required antenna would be at least 20 km, which is not convenient.
- effective power transmitted would be very low, if the size of the antenna is less than 5 km.
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