NOTE:
If the iSAT value is set high, the device may not auto ground balance. In such a case,
lower the iSAT value first. After ground balancing, set the iSAT back to its original position.
Manual Ground Balance
Allows you to manually modify the ground balance value. It is not preferred mostly because
it takes time. However, it is the preferred option in cases where a successful ground balance
cannot be performed using other methods or minor corrections are required to the
automatic balance.
IMPACT
is designed to allow for automatic ground balancing conveniently on any type of
ground. Therefore, it is recommended to perform automatic ground balance upon start up.
However, the ground may not be suitable for automatic ground balancing in some cases
and the device cannot ground balance on such grounds (Except for the COG mode). For
instance, wet beach sand, soils containing alkali or salty water, trashy sites, ploughed fields,
highly mineralized grounds and grounds with very low mineralization are not suitable for
automatic ground balance. In such terrains, you can auto ground balance in the COG mode
and then switch to other modes or try manual ground balancing. However, manual ground
balance requires a skill which develops over time through practice.
To perform manual ground balance:
1)
Find a clear spot without metals and switch the device to the GEN mode.
2)
You need to listen to the sounds coming from the ground in order to perform manual
ground balance. Pump the search coil up and down from about 15-20 cm (~6''- 8'') above
the ground down to 3 cm (~1'') off the ground with smooth movements and keeping it
parallel to the ground.
If the sound gets higher when lifting off the search coil above the ground, the ground
balance value is too low, in other words, the effect from the ground is negative and the
ground balance value needs to be increased by using the ( + ) button. On the other hand,
if the sound gets higher when lowering the search coil to the ground, the ground balance
value is too high, in other words, the effect from the ground is positive and the ground
balance value needs to decreased by using the ( - ) button.
3)
Push the ground balance trigger forward once and release it. The ground balance value
will be shown on the display and remain there for a moment. You can return to the ground
balance screen by pushing the ground balance trigger forward if the screen switches.
Manual ground balance functions within the range
of 0-99. However, each value covers 5 steps used
for fine tuning within itself and these steps are
indicated as multiples of 20 in the Ground Balance
window (GB). For example, ground balance value
shown on the side is 70.80.
Press ( + ) or ( - ) to increase or decrease the ground
balance value, respectively. If the key is pressed
once at a time, the values count one by one and if it is held down, the values will change
quickly.
4)
Repeat the above procedure until the sound heard from the ground is eliminated.
The sound may not be eliminated completely in some areas. In these cases, listen to the
sounds produced when moving the search coil towards and away from the ground to check
if the ground balance is correct. If there is no difference between the two sounds then the
ground balance is set properly.
The device will return to the main screen automatically after a short period of time upon
completion of ground balance. To return to the main screen instantly, just pull and release
the trigger once.
IMPORTANT!
Experienced detectorists adjust the ground balance setting to a slightly posi-
tive response (weak but audible sound is produced when moving the search coil closer to
ground). This method may produce favorable results for experienced users in certain fields
where small targets are searched for.
Ground Tracking (Track)
In this option, the user does not need to make any adjustments. Tracking feature is activated
from the menu by switching it to 01 position. The word ''Track'' is displayed at the bottom of
the screen. The device updates the ground balance automatically as long as the search coil is
swung over the ground and shows the ground balance value in the GB window. It does not
provide any feedback to the user (like the beep sound in automatic ground balance).
While tracking is active, the device can initially produce a loud signal when it detects a
different ground structure (for instance a mineral rock) or a target. In this case, swing the
search coil over the spot where the device produces the signal . If the sound remains the
same and the device shows an ID, it is possibly a target. If the sound attenuates too much
or is lost after a few swings, it means that the device has produced a signal for the different
ground structure or a stone.
NOTE
: It is recommended that you use tracking in the General Search modes (GEN and GEN
(D)) and not in the discrimination or static modes.
Tracking is suitable for use in areas where different soil structures are present within the
same land or in fields where mineralized rocks are scattered widely apart. If you use ground
tracking in areas where hot rocks are intensely present, the device may not be able to elimi-
nate these highly mineralized rocks or you may miss the smaller or deeper metals.
IMPORTANT!
Ensure that tracking is off during air tests. Otherwise, the device will attempt
to perform ground balance on the target and the depth will be reduced.
Ground Balance Value
Ground balance value provides information about the ground you are searching on. Some
typical ground types are as follows:
0-25 Wet salt water or wet alkali soils
25-50 Wet salt water and wet alkali soils covered with dry layers
50-70 Regular, low-quality soils
70-90 Highly magnetic soils, magnetite or maghemite and similar highly mineralized soils,
black sand.
Page 10
Important Details Concerning Ground Balance
1)
Upon start up, the ground balance value is set to 90. The device can perform ground
balance automatically within the range of 20-90 in all modes and 00-90 in the COG mode.
2)
If the ground mineralization is too low, automatic ground balance may fail to work in
other modes except for the COG mode. In such a case, you can auto ground balance in the
COG mode and then switch to other modes or try manual ground balancing.
3)
You can test the accuracy of the ground balance with the pinpoint mode. After ground
balancing, if you receive no sound or a weak one when you move the search coil closer to
the ground in the pinpoint mode, then the ground balance is successful. If the sound gets
louder when you move the search coil closer to the ground, then the ground balance is not
successful. In this case, simply change your location. If ground balance is not possible despite
these efforts, you should continue your search without performing ground balance.
You cannot search in the General Search and Static modes without ground balancing. You need
to use one of the discrimination modes and increase the Disc. value until the noise is eliminated.
4)
Once the ground balance is set, it will remain satisfactory for a long time in most areas.
However, if you encounter an excavated, backfilled or geologically composite soil structure,
a ground balance should be performed again to adapt to the varying soil structure. In
addition, re-ground balancing is recommended if you change the operating frequency of
the device (5kHz/14kHz/20kHz) in certain ground conditions.
5)
When using the optional large coil, pump the coil more slowly and do not keep it very
close to the ground.
6)
In some cases where the iSAT value is set high, the device may not be able to ground
balance automatically. In such a case, first lower the iSAT and after ground balancing switch
it back to its previous position.
TARGET ID is the number produced by the metal detector based on the conductivity of the
metals and gives an idea to the user about what the target may be. Target ID is shown with
two digits on the display and ranges between 00-99.
NOTE:
Keep in mind, large targets will ID higher than expected, even though they may be
of lower conductance.
In some cases, the device may produce multiple IDs for the same target. In other words, the
IDs may be jumpy. This may result from several factors. Target orientation, depth, purity of
the metal, corrosion, mineralization level of the soil etc. Even the direction of the search coil
swing may cause the device to generate multiple IDs.
In some cases, the device may fail to provide any ID. The device needs to receive a strong and
a clear signal from the target in order to provide an ID. Therefore, it may not be able to provide
an ID for targets at fringe depths or smaller targets even if the device detects them.
TARGET ID
Keep in mind that target IDs are “probable”, in other words, estimated values and it would
not be possible to know the properties of a buried object exactly until it is dug out.
IDs of non-ferrous metals such as copper, silver, aluminum and lead are high. Target ID range
of gold is wide and may fall within the same range of metal wastes such as iron, foil, screw
caps, and pull tabs. Therefore, if you are looking for gold targets, digging out some trash
metals is expected.
IMPACT
utilizes 2 different ID scales according to the search modes. In DI2, DI3, DI4, DI99 and
COG modes, the ferrous range is 00-15 at factory defaults. In GEN, GEN (D), STA, STA (D), DEEP,
VLX1 and VLX2 modes, the ferrous range is 00-40. In addition, when the operating frequency
is changed, the Target ID will change as well. This represents the ''Standard'' ID scaling of the
device.
IMPORTANT! At start up, IMPACT will utilize the ''Normalized'' ID scale and not the
Standard ID scale.
In other words, the IDs will not change upon frequency change and
the device will generate the 14kHz IDs in each frequency. However, based on ground
conditions IDs may vary for certain metals.
If you prefer to see the different IDs produced by each frequency, you need use the
''Standard'' ID scale. To switch to the standard IDs, pull the trigger and push the (+) button
at the same time. Letters ''Sd'' will appear on the screen. If you wish to revert back to the
normalized IDs, repeat the same process and letters ''no'' will appear on the screen.
Tables outlining the search modes and ID ranges as well as the probable IDs for each
frequency are placed at the back of this manual. You can easily detach the pages and
carry them with you during your searches.
Coins searched throughout the world are made of different metals and in different sizes in
different geographical locations and historical eras. Therefore, in order to learn the Target
IDs of the coins in a specific region, it is suggested to perform a test with the samples of such
coins, if possible.
It may take some time and experience to make best use of the Target ID feature in your
search area. Different brands and models of detectors produce different target ID numbers.
The numbers vary even more depending on target depth, ground mineralization, and
adjacent metals. But after some practice, you will quickly become comfortable with the
meanings of the
IMPACT
's Target IDs.
Target ID Depth
This setting is not present in the menu.
Adjusts the depth level that the device displays an ID for a detected target. It consists of 3
levels: Hi (High), In (Intermediate), Lo (Low). Factory default is set to ''In''.
The lower the ID depth level is, the higher the ID accuracy and vice versa. At the high level,
the IDs may become jumpy.
To change the ID depth level, pull the trigger and press the up button simultaneously. Each
time you press the up button, the ID depth level will change.
GROUND BALANCE
