The 19 inch really gives a good signal on tree roots,not saying that was what your signal was Bada but just some thing l noticed.Best results l got for depth was High Yield Difficult mode,l could max the sensitivity to 20 and still run smoothly. l did lose sensitivity to smaller targets in this setting, but worked well on the medium to bigger targets.l am not into measurements, l have my test targets buried for 5 years and run my coils over targets to see how the signal is.Still early days for this coil,l see some good operators are not happy with coil, ,but l am, it is heavy though.