Dan-Pa. said:
Not really.....set ground balance can cause loss of depth and sensitivity.....
Not sure what you mean by that Dan? The fixed, or preset systems? Personally, I wouldn't own a preset GB model. Adjustable models can be had at about the same cost as preset, and be more useful in changing ground.
Ground balance is simply balancing the detector to the ground mineralization phase, so it doesn't read that mineralization as a target, or causes it to act erratically, which can cause the "loss of depth and sensitivity" you mention.
Detectors with fixed or factory preset GB are limited to efficient operation, only in ground conditions within the scope of the ground phase employed in the preset. I believe that may be what you referred to in your post. If so, I totally agree! I have detected with folks with preset, (non-adjustable) GB, and seen their limitations. In most cases, they don't even realize they are losing "depth and sensitivity" unless their machine acts erratically. I have seen a few post in these Forums in which the person has quantified that loss of depth. In one case the individual was getting 8" of depth with his fixed GB detector. He moved a distance away and was only getting 4" in bad ground. A 50% reduction! In some cases it makes the detector totally unusable.
Auto tracking systems automatically monitor and set the GB to changing ground conditions, but, they have limitations also! When auto tracking is employed, when a possible target is found, and you move the coil back and forth over the target, the auto track system can actually view the target as bad ground and track it out. That is why the track lock I mentioned on the MXT is invaluable.
Manual systems work fine, but, adjusting manually in bad ground can be tedious.
The "grab" type systems are probably the easiest. One thing I like about many fisher products, is that they give ground phase information, so you can know if the ground conditions are changing. None better than the Fisher F5, IMO, it shows the current numerical ground phase, and the current numerical ground balance setting of the machine. Keep those numbers matched, and the detector is balanced to the ground conditions.