Advertisements
Advertisements
Question
A TV transmission tower antenna is at a height of 20 m. How much service area can it cover if the receiving antenna is (i) at ground level, (ii) at a height of 25 m? Calculate the percentage increase in area covered in case (ii) relative to case (i).
Solution
(i) Range = `sqrt(2 xx 6.4 xx 10^6 xx 20)` = 16 km
Area covered = 803.84 km2
(ii) Range = `sqrt(2 xx 6.4 xx 10^6 xx 20) + sqrt(2 xx 6.4 xx 10^6 xx 25)`
= (16 + 17.9) km2
= 33.9 km
Area covered = 3608.52 km2
∴ Percentage increase in area = `((3608.52 - 803.84))/803.84 xx 100`
= 348.9%
APPEARS IN
RELATED QUESTIONS
Define modulation index.
The carrier wave is given by
C(t) = 2sin(8πt) volt.
The modulating signal is a square wave as shown. Find modulation index.
Explain the need for modulation related to the size of antenna (aerial).
Why is Modulation index kept low?
A carrier wave of peak voltage 15 V is used to transmit a message signal. Find the peak voltage of the modulating signal in order to have a modulation index of 60%
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.
Broadcasting antennas are generally ______.
A male voice after modulation-transmission sounds like that of a female to the receiver. The problem is due to ______.
An audio signal of 15kHz frequency cannot be transmitted over long distances without modulation because ______.
- the size of the required antenna would be at least 5 km which is not convenient.
- the audio signal can not be transmitted through sky waves.
- 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.
A 25 m long antenna is mounted on an antenna tower. The height of the antenna tower is 75 m. The wavelength (in meter) of the signal transmitted by this antenna would be ______.
