This is my first Metal Detector. A Bounty Hunter Land Ranger Pro. This was dug from my back yard hitting a solid 72/73 on the meter. 8 inches later I found part of a 1917 license plate (the rest was completely corroded away). This property has been in my family since built by my great grandfather in 1906 so this was likely off one of his vehicles. My yard is extremely trashy with multiple tones with each swipe, Disc4 mode. Difficult to zero in on just one tone consistently. Would reducing sensitivity help?