My DM800 clone is less than 20 meters from the dish. Current Signal Strength is %54. Would an amplifier improve the signal strength (SNR)?
no, problem most likely is your dish is not perfectly aligned. to do this you first play with elevation (ie. the tilt of the dish). Tilt it gently until you get possible signal strength. Once done its time to gently adjust the dish left to right. You should be able to improve your signal strength dramatically. If not I suspect your LNB is of poor quality and an in-line amplifier isn't going to help that