I am sending the response from one of our engineers regarding your question about pinpointing with the Ace 250.
What you are very likely dealing with relates to an effect caused by mineralized ground. When pinpointing, the detector is switched into a true
All-Metal mode. This means it not only detects all targets but can also potentially detect ground mineralization. Depending on the nature of the
soil mineralization, the effects of this ground detection may result in either positive audio signals or negative (nulled) audio signals as the coil
passes over the ground.
As undesirable as it may be, this is a characteristic of all pinpointing detectors that do not have a ground-balance adjustment, which means
these detectors are operating at a fixed ground-balance setting. This is true of any pinpointing metal detector, made by us or anyone else, that
does not have a ground-balance adjustment (for example, the GTA 500, 550, 750, and 1000.)
The best way to minimize this effect caused by ground mineralization is to use proper pinpointing technique, specifically, to maintain constant
coil height above the ground during the entire pinpointing operation. One preferred method of achieving this is... prior to pushing the pinpoint
button, place the coil on the ground to the side of the target's suspected location. Press and hold the pinpoint button, then maintain contact with
the ground while pinpointing the target's location. This will help ensure the distance between the coil and the ground remains constant throughout
the entire pinpointing process; in this case, that distance is zero inches. If the ground's terrain does not allow for this type of "coil scrubbing" then
do your best to maintain constant separation between the coil and the ground. This is all part of learning proper pinpointing technique. If this is
not sufficiently explained in the manual, we may want to add it.
The addition of a ground-balance adjustment is one of the features we include in our higher performing, top-of-the-line detectors, such as our
DSP-based GTAx-1250, GTP-1350, and GTI's. With these higher-end detectors, the DSP is operating continuously in the background to
automatically optimize the ground-balance setting to minimize the affects of ground mineralization; thereby, providing superior pinpointing
operation. In addition, the GTI-2500 also allows the operator to manually adjust the ground-balance setting, if they so choose.
We hope this helps you some. If you have further questions, please do not hesitate to contact us.
Sincerely, Mary Penson, Customer Service
