I think I've done this right, but I'm looking for some reassurance because I often make stupid mistakes when converting from dB to watts and back again. Thank you in advance! I'm about to graduate in 2 weeks, and this forum has been AWESOME throughout my college career. Kudos to everyone who takes the time to help out. The problem statement reads: "A satellite in synchronous orbit outputs a 4 GHz signal with an EIRP of 100000 W. If the ground based receiver has a sensitivity of -75 dBm, what is the gain required of the receiving antenna?" My equations: (P_receiver) = (EIRP) x (G_free space) x (G_receiving antenna) (G_free space) = [λ/(4*pi*d)]^2 P_receiver = receiving antenna power G_free space = free space gain G_receiving antenna = receiving antenna gain λ = c/f d = 35,800,000 meters (height of orbit for geosynchronous satellite courtesy of Wiki) Converting receiver sensitivity to Watts: -75 dBm = 30 + 10 * log[(P_receiver)] ==> P_receiver = 3.16 x 10^-11 W Solving for G_free space: (G_free space) = [(3.0 x 10^8)/(4 x 10^9)]/[(4*pi*35,800,000)]^2 = 2.78 x 10^-20 Solving for G_receiving antenna: (G_receiving antenna) = (P_receiver)/[(EIRP)*(G_free space)] (G_receiving antenna) = (3.16 x 10^-11)/[(100000)(2.78 x 10^-20)] = 11367 = 10 * log(11367) = 40.56 dB So my final answer is 40.56 dB. Yes? No? Maybe?