We are looking to detect a notch along a hole of a titanium β component. We use a 2D CAD overlay of the borehole to position correctly the probe. The gain is adjusted to have a 80% screen height for the defect. By doing so the geometry echo from the echo is saturated on the screen; the amplitude is 480% screen height. If this echo is used as a reference or to check coupling the operator needs to be able to check the amplitude of the signal without saturation. The dynamic range in GEKKO is 16bit. This allows to have a 800% screen height signal before real saturation. By decreasing the gain by 18 dB in analysis, we can see that the geometry echo is indeed not saturated (image on the right). This is particularly useful when increasing the gain to see tip diffraction echoes, for example, which leads often to the saturation of the corner echo. #Gekko #800% #CADoverlay