28
difference between hot rocks is only 4-5 degrees which leads to difficulties in the identification of
such targets.
In view of the above, it is possible to give some practical recommendations.
1. As accurately as possible carry out Ground Balance.
2. In areas with little to no metal trash use the AGT.
3. In the presence of hot stones, when not using the DHR algorithm, carefully open up the right
border of the sector discrimination to minimize the risk of missing these types of coins.
4. Try to adjust the vector phase of the soil by 2-3 degrees in the counterclockwise direction (specific
value selected experimentally in Depending on the type of soil). To do this, perform the automatic
ground balance procedure. Then press the OK button to enter into manual ground balance mode and
adjust the balance value 2-3 times by pressing - and then check the response of the detector when
scanning area clean. This procedure requires a more careful scanning of the soil. In the case of false
positives channel identification (ST) reduce the angle of the phase by pressing + button until their
disappearance.
When searching on the wet grass (dew, rain) there is an increased risk of false signals in the ST
channel. This effect manifests itself mainly due to the setting of high values of sensitivity in the ST
channel and to the presence of a weak electric conductivity in the dew and plant liquids. To a large
extent (almost completely), this effect can be eliminated by placing the search coil in a protective
plastic case (plastic bag, full-time protection, etc.). In the case of searching in trashy areas it is
sufficient to reduce the sensitivity of the ST channel.
EXAMPLES OF SOME COMMON TARGET VDI’s
VDI data are for units with a 7 kHz, Normal mode, Turbo and Economy off and DHR off.
As we can see, even in the good VDI sectors we have targets that are trash. That is, there will always
be trash items mixed in with the more desirable targets with very similar characteristics.
Also, do not forget that the purpose of VDI is only true in the area of consistent definition of the
instrument and in the absence of other metal objects nearby. For example, a piece of iron underlying
a gold ring will cause the normal VDI of +37 to now read 18/22. And at the limit of sensitivity in the
ground, it may suddenly sound like a deep copper coin with VDI +85. This is not unique to your
device, but for all other devices of this type.
Thus, any decision to dig or not dig a likely trash target is a compromise between comfort verses the
loss of valuable finds. And who knows, maybe 99 times you dig a trash target but on the 100th time
the same VDI rated target will turn out to be a valuable find.
Attention! When using a search coil with a low frequency excitation current VDI readings will have
lower values. Conversely, for higher frequency the VDI readings will be higher.
To Next Page
Loading...
