Figure 15.3 shows a communication system. What is the output power when input signal is of 1.01mW? (gain in dB = (10 \log_{10}(P_{o}/P_{i}))).

Figure 15.3 shows a communication system. What is the output power when input signal is of 1.01mW? (gain in dB = $10 \log_{10}(\frac{P_o}{P_i})$).

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? Calculate the percentage increase in area covered in case (ii) relative to case (i).

The maximum frequency for reflection of sky waves from a certain layer of the ionosphere is found to be (f_{\text{max}} = 9\sqrt{N_{\text{max}}}), where (N_{\text{max}}) is the maximum electron density at that layer of the ionosphere. On a certain day it is observed that signals of frequencies higher than 5MHz are not received by reflection from the (F_{1}) layer of the ionosphere while signals of frequencies higher than 8MHz are not received by reflection from the (F_{2}) layer of the inonosphere. Estimate the maximum electron densities of the (F_{1}) and (F_{2}) layers on that day.

On radiating (sending out) an AM modulated signal, the total radiated power is due to energy carried by (\omega_{c}), (\omega_{c} - \omega_{m}) & (\omega_{c} + \omega_{m}). Suggest ways to minimise cost of radiation without compromising on information.

A TV transmission tower antenna is at a height of 20 m. How much service area can it cover if the receiving antenna is (ii) at a height of 25 m? Calculate the percentage increase in area covered in case (ii) relative to case (i).

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).

If the whole earth is to be connected by LOS communication using space waves (no restriction of antenna size or tower height), what is the minimum number of antennas required? Calculate the tower height of these antennas in terms of earths radius?

A TV transmission tower antenna is at a height of 20 m. How much service area can it cover if the receiving antenna is (ii) at a height of 25 m? Calculate the percentage increase in area covered in case (ii) relative to case (i).

On radiating (sending out) an AM modulated signal, the total radiated power is due to energy carried by $\omega_c$, $\omega_c - \omega_m$ & $\omega_c + \omega_m$. Suggest ways to minimise cost of radiation without compromising on information.

The maximum frequency for reflection of sky waves from a certain layer of the ionosphere is found to be $f_{\text{max}} = 9\sqrt{N_{\text{max}}}$, where $N_{\text{max}}$ is the maximum electron density at that layer of the ionosphere. On a certain day it is observed that signals of frequencies higher than 5MHz are not received by reflection from the $F_1$ layer of the ionosphere while signals of frequencies higher than 8MHz are not received by reflection from the $F_2$ layer of the inonosphere. Estimate the maximum electron densities of the $F_1$ and $F_2$ layers on that day.

If the whole earth is to be connected by LOS communication using space waves (no restriction of antenna size or tower height), what is the minimum number of antennas required? Calculate the tower height of these antennas in terms of earths radius?