In my oppinion to do a proper noise cancel, you need to have the coil on the ground, and keep it completly still while it is running through its test, when the 11 channels are done scanning it will automatically choose the best channel for the area you are hunting, it is important not to have anything under the coil, (matal, trash, ect.) to do a proper noise cancel you need to do a sweep first to make sure the area is cleen from any target, cause the cancel will detect minerals in the ground, and any electrical static that might be in the air,(from power lines, ect.) to find the best channel that will block this interference out. if you happen to do a noise cancel over a coin, the explorer will find a channel that will best filter out this type of target. NOT TO COOL IF THAT HAPPENS..