The transmitter power of 10 000 mW is 40 dBm; the loss of 0.4 in cable is -4 dB; the gain of the transmitting antenna is 300 which is 25 dB; the path loss is 4 x 10 power of -19 or -184 dB. The gain of the receiving antenna is 3000 which is 35 dB; the loss of the cable in receiving systems is -4 dB; the low noice receiver gain of 3 billion is 95 dB. The beauty of dB is we can easily add / subtract the losses of gain which gives a received power of 3 dBm which is 2 mW. We can try the calculation on the amateur radio transmission system. See yaa again. Bye2.
Reference : Allan W. Scott, 1993, Understanding Microwave, John Wiley & Sons.