This has equivalent circuit as a voltage source connectoed to load via 200ft cable. First we need to calculate the input voltage based on the given load output. Then replace output load and cable by 100 ohms load. With this new load calculate output voltage. Step 1: Po = 56.5dBuV = 20*log(V0/1exp-6) solving, we get Vo = 668.34uV therefore Po in dB is Po = 10*log(668.34exp-6/1exp-6) = 28.25dBuW Step 2: The cable loss can be calculated as Cable Loss = 4.5 * 200/100 = 9dB Step 3: This is power in the load of 50 Ohms. The power at the input of the load is give by Po = cable loss + Pin Pin = 28.25 + 9 = 37.25dBuW = 10*log(Pin/1exp-6) Pin = 5.31mW Vin = sqrt (Pin*50) = 515.21mV Step4: No with this input, reaplce 50 Ohm load and cable by 100 Ohms load and calculate Vo Vo = (100 * Vin)/150 = 343.47mV Vo = 110.72dBuV I do not understand what is wrong with the procedure I am following. The answer is given in the bracket in problem statement.