Electronic Communication Systems 2nd Edition by Roy Blake

Exercise 38

A microwave system has a transmitter power of 5 W at a carrier frequency of 6870 MFIz, a bandwidth of 30 MHz, and antennas with gain of 30 dBi at each end of the link. The loss in the waveguides at each end is 1 dB. The receiving antenna sees a sky noise temperature of 100 K. The receiver itself has a noise temperature of 80 K.
(a) Draw a block diagram of the system.
(b) Calculate the carrier-to-noise ratio, in decibels, for a 25 km path.