Yes, when operating in the Fixed GB and All-Metal Mode the results do mean something when the coil is lowered to the ground. Given the internal GB is set correctly, if the Threshold Tone disappears when lowering the coil to the ground then this means the ground matrix is not suited well for Fixed GB and will cause considerable ground noise pick-up, especially when searching in the Disc Mode. In this situation, Manual GB should be used. If the Threshold Tone volume "starts" to increase more than 5 inches above the ground as the coil is lowered, then the ground matrix is too hot and Manual GB should also be used in this situation. Very seldom will anyone actually try to search in the All-Metal Mode while in the Fixed GB Mode. The All-Metal Mode is very sensitive to the ground and the internal Fixed GB control is set to be slightly positive for most ground environments and to prevent excessive ground noise when searching in the Disc Mode.

Now, there are some soils such as we have in the Dallas area that have very little iron mineralization but this soil is very conductive. In many cases it is not possible to manually ground balance to this type soil as there is not enough mineralization to MGB. In this environment, when the coil is lowered to the ground in the All-Metal Mode in either the Fixed or Manual GB modes, you will always get a positive threshold response (similar to wet salt sand). In this case, simply use the Fixed GB as the important issue is to operate without ground noise pick-up. You will lose very little depth in these conditions because of the lack of iron mineralization. I hope this helps.

Thanks,

Troy