Question

Find the power level of the earth station receiver and the antenna gain at the earth receiver station so that overall carrier to noise ratio is 15 dB. Miscellaneous downlink losses are 0.5dB. Earth station is located at -2dB contour of satellite transmitting antenna. The earth station receiver has the following noise temperatures: noise temperature of the input signal is 25K, noise temperature of the RF amplifier is 400K, noise temperature of the mixer is 450 K and the noise temperature of the IF amplifier is 550K. The gain of the RF amplifier is 35 dB, the gain of the mixer is 0dB and the gain of the IF amplifier is 20dB. Assume standard frequency allocation of 11GHz for the downlink in Ku-band. Satellite parameters are: Antenna gain 25 dB; Receive system noise temperature 500 K; Transponder saturated output power in Ku band 40 W; Transponder bandwidth 36 MHz; Signals: FM-TV analog signal. Earth station receiver IF noise bandwidth is 27MHz. Minimum C/N overall = 15 dB. Perform your calculations using decibels. (Boltzmann’s constant in decibels is k=-228.6 dBW/K/Hz)

Answer 1

To calculate the required power level and antenna gain at the earth station receiver, one must consider the noise temperatures of the receiver components, their gains, and downlink path losses using the given parameters like Boltzmann's constant, antenna gain, and receiver sensitivity.

Step-by-step explanation:

The question pertains to satellite communications, specifically finding the power level of an earth station receiver and the antenna gain at the earth receiver station required to achieve a carrier to noise ratio (C/N) of 15 dB. To answer this question, it's necessary to consider various factors such as the noise temperature of different components in the receiving chain (input signal, RF amplifier, mixer, IF amplifier), their gains, and the downlink path losses from the satellite to the receiver, including the satellite's antenna gain, and miscellaneous losses.

Boltzmann's constant in decibels is already provided, and this will be used to calculate the noise power based on the bandwidth in the communication link. Antenna gain and receiver sensitivity are critical factors that must be analyzed to achieve the specified carrier to noise ratio.