pax said:
can I set my GB auto or manual then put in my offset? example if GB 45 and set a pos offset of 6 to make GB 39 will the machine only adjust as needed between the two 39 and 45 ?
You can set your Ground Phase manually or automatically, and implement an offset. However, when you implement the offset, you have changed the ground phase to the new level, represented by the offset you have applied to the ground phase (that was chosen when performing you ground balance). That setting will NOT fluctuate or change, unless you implement Tracking or physically change the offset. Or, adjusting the original ground phase number (by re-ground balancing).
When you set the X-TERRA to Tracking, it will constantly monitor the effects of mineralization and continually update the ground phase setting so that it neutralizes the effects of the ground. If you implement Tracking with a ground balance offset, the X-TERRA will again monitor the effects of the mineralization, and continually update the ground phase reading. However, with an offset, the X-TERRA will also implement the number you chose as an offset (either positive or negative), and incorporate that offset into the tracked ground phase setting.
Ground is a conductor. Properly setting your ground balance is the simplest form of discrimination, in that you are trying to set the detector to neutralize the effects of the ground. When the ground phase is properly set, you should hear no change in Threshold when you sweep the coil over the ground (with no targets present). By definition, higher levels of mineralization represent more positive soil conditions. Lower levels of mineralization represent more negative soil conditions. The X-TERRA analyzes the effects of both conductive and magnetic mineralization, and can determine what ground phase setting best neutralizes the effects of that soil.
Here is where it can become confusing.

Simply put, it is a matter of defining ground phase vs. ground balance. Higher levels of mineralization are best neutralized by implementing a smaller ground phase number. And, soils with lower levels of mineralization are best served by implementing a larger ground phase number. So, if higher levels of mineralization represent more positive soil conditions, and the X-TERRA compensates for those levels with a smaller ground phase number, we can determine that lowering that ground phase number makes the X-TERRA operate with a more positive ground balance. On the other hand, if you raise the ground phase number, you are adjusting the ground phase for more negative soil conditions. Whether we change it + or -, each number we change the ground phase represents a 2 degree change in the ground phase angle. The phase angle is a measurement of time, between the transmitted signal and the received signal. This is referred to as the time constant. The time constant is used to provide the information that determines a target