Dear colleagues. please help in solving the actual problem: Our company operates in the field of space communications . For reception and transmission of signals via satellite is used parabolic antenna with a diameter of 12 m Frequency of received signal is 4000 MHz. The receiver is a Low noise amplifier with an effective temperature of noise 40 K. At times, the noise level in the receiving circuit increases sharply in 8 times, then after some time, it returned to normal. The same antenna near shows no increase in noise. What might be the cause of the noise ? How can we remove it ?