The GP Extreme

The first of the GP Series and was upgraded to the 3000. Has it done its dash? I dont think so. In the last month I have heard of two Extremes which have been more successful than the 4500, particulary with the latest Coiltek Goldstalker Coils. It would be interesting to hear what users still say about it.

This is a copy of the GP tips "bible" written by minelab.

To get the best from you GP Extreme and to ensure your machine is operating at peak performance at all times please follow the instructions below.
ONLY SEARCH IN "TRACKING" MODE IF THE SOIL IS PARTICULARLY NOISY. OTHERWISE ALWAYS SEARCH IN “FIXED”
When ground balancing the detector, set to "Tracking" and initially pump the coil up and down, then sweep the coil from side to side at typical search height above the surface. Switch from "Tracking" to "'Fixed" whilst sweeping the coil from side to side at typical search height.
It is important that while searching, you regularly re-balance the detector by switching back to "Tracking" anytime the ground noise increase.
If the ground noise abruptly and obviously increases as the coil is lowered onto the soil surface, detect such an area with the coil held at least 2 or so centimetres above the soil surface, or better, at or above the height at which the abrupt ground signal commences.
Signal Control: In quiet ground a higher setting can have an advantage, in noisy ground a lower setting should be chosen. High settings cause more threshold chatter. Set the control to suit personal comfort for the ground conditions and threshold stability.

NOTE
The unit ground balance setting will drift for the first several minutes after the unit is turned on whilst in "Fixed "and so the unit will have to be re ground balanced frequently during this initial period.
Soils such as those described in Point 4 are rare in gold fields, but do occur.
The above procedure is essential for optimal detection depth, especially for larger nuggets.

A Few More Handy Hints From Minelab

Slow Sweep technique. I know we have all been teaching our customers for years the importance of operating a slow sweep across the ground. With the GP extreme, this is all the more important that a slow sweep technique be used.
Setting Threshold. So that your customers can operate with a relatively smooth threshold there are a couple of important things to be aware of. Firstly make sure that they are not trying to use too high a setting of the Signal control. When this is turned up too far the threshold will become unstable.
It can also assist in setting the threshold to the right level for your ears, if you turn the threshold control to above the level you desire and then reduce it using the volume control. Also remind them to use the tune button to eliminate electrical interference.
As is the case with all detectors, if the mineralisation is excessive, the operator may need to lift the coil off the ground rather than keeping it right on the ground.

If the ground is quiet to medium mineralised there can be depth advantages if Fixed position is used for searching and just switch back to Tracking from time to time when required. If the ground is variably mineralised and noisy, then Tracking is the preferred position.
Remind customers that after choosing a new position for the RX or soil switch, the detector should be again ground balanced.
The GP extreme does consume power at a faster rate than did the SD detectors. For this reason it is important that batteries be fully charged.

Air or newly buried target tests are not an accurate method of determining the depth performance of the GP extreme. The only way to truly see the impressive depth of the GP extreme is to use it. If the GP extreme is being used in association with an SID, once a target signal is located, both detectors should be put across it. The GP extreme will find targets that the SD won't see and will often give a better, clearer signal on those that the SD gives a 'maybe' signal on.