Assignment:
An antenna with gain 7 dB and noise temperature 120 K is connected to a coaxial cable. The coaxial cable is long 10 km and has a specific attenuation of 2 dB/km at the frequency 1 MHz. The cable is followed by an amplifier with gain 20 dB and noise figure 5 dB. Assume the impedance matching conditions between al the system devices. The signal, with bandwidth 10 MHz is centered at the frequency of 100 MHz:
a) What is the available power (in dBm) at the amplifier output if at the antenna input we have a useful signal with power Pi,Ant = 10 dBm?
b) What is the noise power (in dBm) at the amplifier output?
c) What is the noise power (in dBm) at the output if the cascade cable + amplifier is replaced by two cables of 5 km (with the same characteristics of the previous cable of 10 km), each followed by a repeater with gain 10 dB and noise figure 6 dB?