AKA Signum MFT 7272? User manual

Discriminating Metal Detector
Signum MFT
7272М
Attention!
Please read
this manual
thoroughly.
Instruction Manual

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Contents
GENERAL INFORMATION--------------------------------------------------------------------------------------------------4
GENERAL DESCRIPTION OF THE DEVICE---------------------------------------------------------------------------4
PACKAGE CONTENTS------------------------------------------------------------------------------------------------------5
TECHNICAL SPECIFICATIONS---------------------------------------------------------------------------------------------5
GETTING STARTED----------------------------------------------------------------------------------------------------------6
POWER SUPPLY-----------------------------------------------------------------------------------------------------------------6
CONTROLS AND CONNECTIONS---------------------------------------------------------------------------------------7
DISPLAY SCREEN--------------------------------------------------------------------------------------------------------------9
SENSITIVITY CT, PB SENSITIVITY / CT VOLUME----------------------------------------------------------------9
GROUND BALANCE--------------------------------------------------------------------------------------------------------10
DISCRIMINATION SEARCH MODE AND SETUP-------------------------------------------------------------------14
SEARCH MODE “ ALL METAL “----------------------------------------------------------------------------------------15
DYNAMIC AND STATIC MODES OF OPERATION------------------------------------------------------------------16
MODE “TURBO”-------------------------------------------------------------------------------------------------------------17
MODE “ECONOMY”--------------------------------------------------------------------------------------------------------17
MODE S ALGORITHM------------------------------------------------------------------------------------------------------17
MULTI-FREQUENCY-------------------------------------------------------------------------------------------------------18
PARAMETER MENU--------------------------------------------------------------------------------------------------------19
ADDITIONAL MENU (ADD. MENU)-------------------------------------------------------------------------------------22
USER PROGRAMS----------------------------------------------------------------------------------------------------------23
USING THE HODOGRAPH FOR IDENTIFICATION --------------------------------------------------------------25
SEARCHCOIL REPLACEMENT-----------------------------------------------------------------------------------------26
SEARCH AND IDENTIFICATION METHODS-----------------------------------------------------------------------26
SEARCHING FOR LARGE/ FLAT NON FERROUS TARGETS WITH A HIIGH
VDI ANGLE ------------------------------------------------------------------------------------------------------------------30
EXAMPLES OF SOME COMMON TARGET VDI’s-----------------------------------------------------------------32
WARRANTY INFORMATION--------------------------------------------------------------------------------------------------------------------------------------------------------------33
QA/QC CERTIFICATE------------------------------------------------------------------------------------------------------34

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GENERAL INFORMATION
Metal detector SIGNUM MFT 7272M is designed to search for and identify metal
objects in the dielectric (dry sand, wood, etc.) and low conducting media (soil, brick walls,
etc.).
Some applications of use are:
•Criminal;
•Engineering;
• Housing and community services, construction and fire-fighters to search
for underground utilities, pipelines, cables, manhole wells etc.
• Archaeology and treasure search.
The device is designed to operate under the following conditions:
- Ambient temperature from -20 up to +50°c (-4 to 122 F);
- Relative humidity up to 98 per cent at temperature of 25°c (77 F);
- Atmospheric pressure from 630 to 800 mm Hg.
0BGENERAL DESCRIPTION
The Signum MFT 7272M is an eddy current selective metal detector that works
on the principle of induction balance. The main distinguishing feature of this model is the
use of its original software and hardware. Our multi-frequency technology (MFT) allows
the use of any search coils manufactured by us, regardless of their operating frequency
(Hz). That is, the device itself will make adjustments and calibrate to the selected coil.
The device uses the original technology of signal processing sensor-technology
space and harmonic filtering (SFT), minimizing the hindering effect of ferrous soil
(salinity) and, thereby, increasing the reliability of the identification of deep and
small objects.
Basic search mode –Dynamic search mode, i.e. detection of an object occurs with
constant motion of the search coil.
To pinpoint the exact location of the detected object the device has a static mode of
operation (Pinpoint).
The device has 2 methods for identifying the object detected:
-Audio programmable multi-mode,
-Visual (Hodograph, VDI value, rating (level) signal-RS).
The device has two independent search channels: RT and ST.
The RT channel (real time) works in real time, i.e. sound indication is given
simultaneously with the movement of the search coil over the object. Sound indication in
this channel is a single-tone signal, volume and frequency of which can change when an
object approaches the search coil. Also using the duration of the tone we can get an
estimate of size of the target detected.
When the received signal from an object exceeds the specified RT threshold, the
channel generates the ST audio or short tone.
Channel ST (short tone) is the audio identification channel for the type of object
detected. When the received signal exceeds the threshold of the RT channel the detector
issues a short audio tone (ST), and the screen displays the hodograph (vector time curve) of
the detected object.
The frequency of the short tone indicates the type of object detected (high tones –
non ferrous metal, low tone - ferrous metal). The number of tones can be specified by the
user (the default is 4 tones).

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Each channel has an independent adjustment of its sensitivity. The
sensitivity of the RT and the sensitivity of ST.
The RT channel has a higher sensitivity than the ST channel and its main
objective is to locate the object and alert the operator that there is something there.
The Signum MFT 7272M is equipped with mode (Turbo). This is a high
coil current mode, which is used to improve response from good signals at depth.
There are also 4 custom user programs.
The detector is equipped with a manual or automatic ground balance
system with the ability to adjust auto track rate (APB).
PACKAGE CONTENTS
•The electronic unit with a telescopic pole 1 ea .
•Search coil - eddy current transducer (ECT) 1
ea .
• Magazine for 6 batteries (type AA)* 1
ea .
•Operators Manual 1 ea .
•Headphones** 1 ea .
•Carrying Bag** 1 ea .
*) batteries sold separately
**) purchased separately or as an option .
TECHNICAL
SPECIFICATIONS
The maximum detection range of metal objects
(air test with coil Ø260mm DD) via RT:
• 25 mm dia. coin - 60 с м(23.5 in) ;
• Helmet - 150 с м(59 in) ;
Display modes:
• Audio, 5 modes (RT, RT-M, RT-ST, RTL-ST, STP);
• visual (LCD display with a resolution of 128x64 pixels).
Search modes:
•
All metals;
• sectored discrimination with 2 ° step.
Control modes:
• Dynamic programmable;
• Static with adjustable threshold.
Power Supply: - 6 batteries (type AA (LR6));
Continuous operation time: - 16-18 hours in normal mode, 6-7 hours in Turbo mode
(Rechargeable batteries 2500 mAh) - up to 40 hours in economy mode
Overall dimensions, mm:
• Telescopic rod - 1200 (Max .);
• Electronic unit - 12 0х 70х115;
• Search coils - Ø 260 mm, Ø 380 mm, 150x260 mm, 240x 3 20 mm
Weight of the device: - 1300 g (without battery)
The device allows the ability to work in water depths of up to 15 meters, without
submerging the control box.

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GETTING STARTED
Assemble the metal detector. To do this:
- install the appliance in a metal bar;
- tighten the Collet Chuck;
- install the inner (plastic rod) sensor;
- install the rod with the sensor in a metal bar to desired length, using the tabs and
holes in the rod
- tightly and evenly wrap the sensor cable around the rod. Freely hanging cables can
Cause falsing;
- connect the sensor connector to the electronic unit.
WARNING! Do not over tighten the attachments and fittings for the telescopic
shaft.This applies in particular to the
plastic bolt for the search coil
and shaft collets.
Thanks to a specially designed three-knee construction
shafts do not need to be disassembled for transportation,
simply push the knee shafts into each other all the way
and the device is ready to be carried compactly (fig. 1)
POWER SUPPLY
The device is powered using 6 AA
batteries or 6 rechargeable NIMH. Rechargeable
batteries and charger are not included and must
be purchased separately. We recommend that
you use NiMH batteries from SANYO, ANSMANN
2500 capacity-VARTA or 2850 Ma/h. The use of
standard alkaline batteries is possible but not cost
effective as the rechargeable batteries pay off
after 4-5 recharges.
fig 1
When using batteries, with a capacity of 2500 Ma/h, continuous operation is
approximately 16 hours in the main mode and 6-7 hours in Turbo mode.
Several recommendations on the use of nickel-metal hydride batteries:
-Avoid fully discharging the batteries with each cycle use as this shortens their
lifespan. Slight "memory effect" is eliminated by one complete discharge approximately
once a month.
-After extended periods, of storing the device, it is usually good practice to
fully discharge and charge the batteries a total of 4-5 times.
-Remember that due to the self-discharge nature of the batter capacity falls (by
About 5% per day , so it is advisable to charge batteries before each use.
-DO NOT use rechargeable batteries that have different capacities in the same set.
WARNING! When connecting the battery magazine to the device connector insure
the battery is properly connected (polarity is indicated on the battery cartridge) and
insure the voltage source is correct. In the case of incorrect polarity or improper voltage the
device can be damaged
.

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CONTROLS AND CONNECTIONS
Appearance of the device is shown in Figure 2.
Sensor
(coil)
Electronic unit
Grip
Armrest
Telescopic shaft
Socket for headphones
Battery compartment
Fig. 2
On the rear panel of the device are the coil connector, on/off switch and the
serial number of the device (fig. 3).
Located on the front panel are the LCD graphic display (with a resolution of 128 x 64 dots)
and 11 touchpad controls (fig. 4).
Fig.3

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Fig. 4
Sets the sensitivity of the ST (short tone) channel
Sets the sensitivity of the threshold RT channel (Real Time)
Sets the volume of the audio
Select the Discrimination edit mode
Switch between all metals/discrimination
Navigate through the menu and change the settings, also turns the Turbo mode
on/off
.
Move through the menu and change the settings, as well as turn on/off the S
Algorithm
Switches between User Programs
Access the Ground Balance modes
Confirms the selected settings. Selects a menu item. In search mode switches
between Static and dynamic (Pinpoint) modes. In ground balance mode switches
between Auto and Manual GB.
Button to enter the Main Menu

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DISPLAY SCREEN
In search mode the display device displays the Hodograph information of
detected objects and information about the current operation modes (Fig. 5).
VDI Number Signal level
Battery charge level
T-Turbo mode is enabled (see page 14)
Number of the current user
program 1-4 (see page 14)
A-enabled auto adjustment ground balance
(see page 17)
С–Static Mode enabled (pinpoint) (see page 13)
S –S-Algorithm enabled (see page. 1 4)
М–Metal Trash mode is enabled (see page 16)
Fig. 5
VDI-number “Visual Discrimination Indication”. This is the index of electrical
conductivity of the object or the angle between the vertical axis and the predominant
direction of the hodograph (time curve). In this case, hodographs which are on the left
side of the screen have a negative VDI, and the right - have a positive VDI number. The
amplitude of the signal, from detected objects, is displayed in standard numerical units
ST SENSITIVITY, RT SENSITIVITY / VOLUME
This section introduces the three main parameters that you'll use most often. For
each of these settings there is an individual button on the control panel.
SENSITIVITY ST [1 .. 14]. Increasing this setting allows you to increase the depth
of targets you're searching for, but it reduces the accuracy of identification and increases
the risk of false positives. The recommended value is 9-10.
Warning! Setting of the ST sensitivity above 11, and especially 14 can lead to
a significant increase in the amount of false positives from the soil in high
salinity or when bumping the search coil.
SENSITIVITY RT [0 .. 9]. Adjusts the sensitivity of the threshold or RT channel
you hear constantly during the search. The value of this parameter is set as a compromise
between sensitivity and comfort. Increasing this value increases sensitivity in the threshold
channel. However this can reduce the comfort in searching. Recommended settings are 6-7.
VOLUME [1 .. 9]. This setting adjusts the overall volume of the audio response
from detected objects. Select the value based upon individual comfort preference. The
current values of these parameters are displayed on the screen above the relative buttons (Fig.
6).

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To change any of these
settings press the appropriate
button. The value of the selected
option is highlighted on the screen
with a rectangle around the
appropriate value.
Press the button
Fig. 6
Or to set the required
value. In order to exit the
parameters simply click the button again .
When neither the RT, ST or Volume
values are displayed on screen - the buttons and will now act as
on / off modes for the Turbo and S-algorithm, (see below)
GROUND BALANCE
Balancing the device to the ground is the single most important part of the
device settings for accurate search results. Improper ground balancing can result in
decreased responses to targets and may result in instability as well as an increase in false
ground signals.
To explain the basic physics behind the ground balance procedure. Every object
has its own shape, conductivity and magnetic component, which together are called the
VDI (Visual Digital Index). Remember that the VDI is the angular response that is
numerically equal to the angle of deflection of the signal vector time curve (hodograph
display) on the vertical axis. The soil, or ground, depending on the degree of
mineralization (presence of iron oxides) imposes its signal on the target signal thus
changing the VDI upscale. This is especially true on small or deep targets, as well as large
highly conductive targets (copper, silver, aluminum). This can actually push these high VDI
targets up and over into the high negative VDI range known as “VDI wrap around”. To
minimize this effect, it is crucial to perform a proper and accurate ground balance
procedure.
The basic objectives of balancing:
1. Make the soil 'invisible' to the instrument, i.e. exclude false signals
from the ground where there is no target.
2. Install the correct (standardized) reference system number for the VDI .
When receiving a signal from both the ground and a detected object the
detector must subtract mathematically the signal from the ground in
order to display a correct VDI indication of the detected target
Keep in mind that when performing “air tests” inside after the detector has been
previously balanced in soil may result in incorrect VDI readings. This is due to the
correction factor for the VDI previously set in the last ground balance. This may result in
the loss or “invisibility” of large aluminum, silver and copper targets. If the ground setting
is too positive the VDI will be offset positive and vice versa if the ground balance is
negative.

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This may also lead to targets air testing as iron, as well as a false increase in
sensitivity when air testing.
Remember that for every 1 degree of ground balance offset from the 0 or
neutral point we get a corresponding increase or decrease in the VDI scale for a
given target. IE a 1 degree+ ground balance will increase the VDI by +1.
For example, if you are air testing a large copper coin that would normally give a
VDI of +82 to +84 but is now air testing with a VDI of -86. The result is that the device
ground balance is set +10 to +12 degrees too positive for performing an accurate air test.
Balancing with a piece of ferrite is required before performing an "air test" of the
device. Put the device on a non-metal surface, turn on automatic ground balance mode,
count to three, then bring the ferrite to the center surface of the coil from a distance of
25-30 cm (10”to12”) to complete the balancing procedure. Puzzled? Let's make it easier:
Take a CD and pass it flatwise in front of the search coil.
If the CD gives a vertical hodograph and VDI of 0 (+1 or -1), then the device is ready for
“air" tests.
If the VDI of the CD differs from these values, then in auto GB click (to enter manual
GB) and adjust the phase of the ground balance in the desired direction. When the VDI of
the CD is at 0 (+1 or –1) your device is ready for air testing.
BALANCING PROCEDURE.
We would like to bring your attention to the automatic balancing procedure developed by
experienced users .
1. Find a metal-free area. You can find it by the threshold tone response in RT mode.
On an unbalanced device there will be a response to the clean ground, however the
sound will be soft and "diffused", without a strong localization. While the sound
would be sharp and with a strong increase in sound above a metal object. Select an
area with no localized sharp threshold tone increase while swinging the search coil 5-
10 cm to the left and to the right above the ground. If there is no localized sharp
threshold tone increase then the area is suitable for balancing.
2. Having found the metal-free area, raise the coil 30-40 cm above the ground
press wait for 3 seconds, and move the coil to the ground smoothly but
not too slow.
Warning! Do not move the coil to the ground closer than 10% of the search coil
diameter (for the searchcoilØ26 cm –2-3 cm). This is related to the change in the
pattern of the search coils physical interaction with the ground in what is called
the "Close Zone" and it may impact balancing accuracy resulting in false
responses in clean areas with high levels of sensitivity.
A short tone (Hum) signifies the completed balancing procedure. If there is no tone
or it does not sound during lowering, but sounds when moving up, repeat the procedure
with the same formula: 30-40 cm above the ground, 3 seconds, and then lower the coil to
the ground. Follow the ground vector on the screen during the process. Its shape should
be a strait, slightly trembling line, on the horizontal axis of the ground scale.

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If it makes sharp angles or is “chaotic” on the screen, this means that you are trying to
balance near a metal object in the ground. In this case, the device may perform a ground
balance, however it will be incorrect and you will notice multiple false signals from the
ground. If this occurs, simply re-balance the detector in an area clear of any metal
targets.
Once you have chosen a clean location to balance the detector and have done so,
note the value in the lower left hand corner of the ground balance screen. Now, should
you chose to ground balance again later on and there is a sharp difference between this
value now, as compared to the previous ground balance, there is good reason to suspect
that there was metal close by and you will need to ground balance again.
If the coil all the same was a metal object, giving an automatic balance (items
with VDI close to 0, e.g. foil), the device will give two consecutive tones, similar in tone to
that of iron in the search mode, while at the same time the screen will display an
exclamation point within a triangle. Accordingly, you will need to ground balance again on
a clean spot of land.
After balancing, in the lower left corner of the screen will display a numerical value of
balance (phase), this is the amount by which the device will adjust the VDI, excluding the
effect of the soil.
In the right corner of the screen it should be noted that the average phase
angle ground balance is different for each instance of the device and can also depend on
the technological variability in parameters of the coil and the ambient temperature.
However do not forget that your device remains in the automatic balancing
mode and at any moment may deem it was time to rebalance to your shovel, boots, or
hunting partner. If you want to review the results and values of the current automatic
ground balance procedure press to enter manual mode and disable automatic
balancing. In the upper right corner of the screen will appear M instead of the letter A. To
exit the ground balancing, click on the instrument panel. Switching between modes
is as simple as performing successive clicks of. While in the manual balance
mode by pressing or one is able to adjust
the ground balance in the proper direction. Bob the coil
vertically above the ground (rising to 20 -30cm / dropping by
3-5cm), making sure that the vector of the soil is along the
horizontal axis and that the hum is gone when raising or
lowering the coil.
Vector of improperly balanced soil (fig 7)
fig. 7
Vector of properly balanced soil (fig 8)
When working on the ground with uneven salinity, Fig. 8
such as arable land, it is not always possible to accurately ground
balance the unit in automatic mode. This can be due to the uneven or
lumpy nature of the soil. This can sometimes leads to false responses from the identification
channel. In this situation the phase of the ground balance can vary by more than 3

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degrees. If you encounter this problem then perform the ground balance procedure
as follows.
Find a clean patch of ground with a width of 60 centimeters. Switch to manual ground
balance and making short horizontal search sweeps with a width of 50cm at a height 3-5cm
above the ground, you will see a straight line on the ground the screen (if the line jumps,
then there is metal present). In this case, if the balance is wrong, you will hear a buzz from
the soil and the soil line on the on the screen will not be horizontal.
Press and until the line is horizontal and the buzz disappears.
Your device is fine-tuned to the ground.
For a small increase in the depth of the identification of large silver and copper
coins (kettles, basins and other large pieces of highly conductive metals) it is possible, after
performing automatic ground balancing, to enter the manual balance mode and set the GB
point from -1 to -2 from the automatic GB reference point.
Care should be taken when setting the ground balance point either negative or
positive. When set negative it increases the possibility of receiving false positive responses
when bumping the coil on vegetation or the ground. When set positive you risk the chance of
losing sensitivity to large silver or copper coins that will either become “invisible” or ID as
iron.
In the event that a “clean” patch of ground is not found you can excavate a small
amount of local soil (1-1.5 kg), removing all metal objects, and place in a bag for
convenience. Now lean the detector with the coil facing up against a bush or tree with the
coil at least 40-50cm off the ground. With the bag of soil in hand you can now and press
the GB button and count 1,2,3. Then smooth and slow, (starting from a distance of
30-40 cm) present the soil to coil. (As if doing auto balance on the ground in the normal
mode, but now you are moving the soil to the coil instead of vice versa)
Placing the excavated soil on the ground is not desirable. Since you were not able
to perform a ground balance previously, due to the presence of metal in ground, placing the
bag of soil on the ground may cause an incorrect ground balance.
Attention! If the signal from the ground is too small (such as quartz sand) and the
auto balance cannot be performed then the balancing procedure can be
performed either by using a piece of ferrite or a piece of red brick. These can be
placed on the ground and the auto balance procedure performed. In principle,
using the procedure for balancing for “an air test” will also work and you may set
the balance point 1 or 2 degrees negative if you are searching for large objects.
Sharp temperature changes on the search coil may impact balancing accuracy,
the balance may shift and become incorrect with such changes. That is why, if you take the
device from a heated car and start working in a low temperature conditions (early spring, late
fall), rebalance one or two times while the coil adapts to the ambient temperature.
In case of large temperature drops of more, than 15°С(compared to a normal air
temp of 20C), we recommend that you perform electronic module and search coil

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adaptation procedure one more time (see Search coil Replacement). In this case the
processor of your detector will choose the optimum frequency of the excitation current for
the current temperature conditions.
In saltwater beach operations and other complicated soils with high conductivity we
recommend you use the "Economy Mode" option for better ground balance accuracy.
Sometimes decreasing sensitivity will allow for a more accurate ground balance especially on
beaches.
In rare cases, such as after replacement of the coil or attempting to balance on a
metal object, a situation may arise when you cannot perform an automatic ground balance.
This occurs because the current value of the phase vector moves out of the locked
system acquisition sheet (such as a significant change in ambient temperature).
You can solve the problem by balancing in manual mode. To do this, while
in the automatic balancing press the t o g o t o t he
manual mode and using the buttons and get the vector of the
ground signal moving from left to right in strictly the horizontal direction. After that, the
balancing procedure will operate normally.
DISCRIMINATION SEARCH MODE AND SETUP
Discrimination is the ability of the device to respond to certain types of objects
and ignore the others. For example, you can configure the appliance so that it will
respond only to objects of non-ferrous metals while ignoring everything else. In some
cases, this allows you to increase the comfort of the search. Be aware, however, that the
more discrimination that is used there is an increased risk in missing valuable objects. In
any event, the choice is yours.
The discrimination range is set to the position and width of the search sector.
The metal detector will respond only to those objects that
have travel time curves (Hodographs) which fall between
the left and Right border sector. For example, to search for
non-ferrous objects your sector search screen may
look like that in Fig. 9.
Pressing Button allows the user to
fig.9 quickly switch between modes “All Metal” and
“Discrimination” and then back again.
The sector on the screen indicates that you are in a discriminatory setup. An
Audio response will occur only on those objects that fall in the clear Hodograph area while
targets that fall within the hatched area will not generate an audio response.

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To configure the discrimination, click. Now, by positioning the left and right
edges of the search sector you can set the desired area (level) of discrimination.
At the top left and top right of the screen are the current values of the search
sector. These are in degrees of inclination relative to the vertical axis of the screen.
The currently selected border sector is
highlighted by a rectangular frame (fig. 10).
To change the position of the border sector
use the search buttons and
To set up another border sector
Click.
fig. 10
As already noted in the discrimination mode, due to the influence of the soil, there
is a risk of missing objects if the search sector borders are set too narrow.
To exit discrimination click
SEARCH MODE “All Metal”
Using the search mode "all metal “as opposed to “discrimination” mode you can
detect any metal objects whether they be ferrous or non-ferrous.
Which mode is best to use is a personal preference.
However, it should be noted that searching in the discrimination setup can
miss some of the weaker signals from good targets. This is due to the effect of the soil on
the vector signal of the target and causes the signal to go beyond the search vector
boundary.
The disadvantages of the “all metal “mode can include difficulty working in trashy
areas due to the extreme amount of signals and sounds received. Since the sector
boundaries in the “all metal" mode are fully open, it may be full of signals from so called
“hot rocks”. The detector will issue high-pitched signals from these objects. This is useful for
finding stones of meteorite origin. Identifying these “hot rocks” can be done by noting the
high ratings from the VDI (+86) and the stretching of the signal. If these are bothersome you
may use the discrimination mode and set your sector boundaries at -86 to +86 respectively.
This will act much the same as “all metal” accept with the elimination of the “hot rocks”.
You may also use the algorithm suppression “Disc. of Hot rocks “(see page 15).

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DYNAMIC AND STATIC MODES
Dynamic mode is the main mode of operation of the detector. It is characterized
in that the processor constantly adjusts to relatively slow changes in ground conditions.
Therefore, in this mode, the instrument responds to the desired objects only when
moving the coil. If the coil is stationary over an object, then after a while the sound will
disappear. This is the primary mode your detector is in every time you turn it on.
Static mode is used as an additional and serves mainly to clarify the location of
the found object (Pinpoint). Unlike dynamic mode there is no constant adjusting and
therefore, it is not intended for
a lengthy search. To switch the appliance
from the basic search mode to static mode (Pinpoint)
Click. In the right-hand side of the
Fig. 11
Screen there will appear the letter "C", and on the left the
value of the gain for the static mode along with the ability
to change this parameter by using the buttons
and (fig. 11).
The gain of the static mode is selected experimentally depending on the specific
conditions. The choice of this parameter will depend on the relief of the ground, littered
area, temperature changes, etc. We recommend starting values of 6-7.
As already mentioned, the active
mode (pinpoint) is used to determine the
the exact location of the object.
Let us give some practical
tips on how to
Use this mode.
After locating an object, in the static mode,
and deciding it is worth digging it is time to
define its exact location. To do this,
move the search coil off of the approximate
center of the target either left or right (line A
see Figure 12). Then turn on the
static mode (Pinpoint).
As accurately as possible, while
maintaining the distance between the
ground and the coil, scan
the object backwards.
Determine on line A the location
(coordinate) where the tone of the sound was
the highest.
Fig.12

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Then move the coil away from the target perpendicular to the primary direction
(A) scanning (e.g. forward) along this line .
This retraction of the coil in this direction must pass through the original coordinate. Re-
enable the static mode. Scan the object along the line as accurately as possible keeping a
minimum distance between the ground and the sensor. The recorded coordinate of the
maximum frequency tones sound on line B, will determine the exact location of the
object.
To return to the dynamic mode press the button again
.
MODE “TURBO”
In the "Turbo" mode the search coil operates at the forced excitation current.
This mode allows you to increase the sensitivity of the device and to improve the
immunity of the device from external electromagnetic interference.
Attention! The “Turbo” mode greatly increases current consumption and as
such battery operating time is greatly reduced!
Switch to TURBO and back by using the button while in search mode. It is
necessary to ensure that the settings ST/RT sensitivity and volume on the display
screen are not displayed.
MODE “ECONOMY”
In the "Economy" the sensor operates at the minimum excitation current. This
mode allows you to improve the comfort of your search on soils with a complex and
variable salinity (for example in the surf of the beach), or at locations with extreme iron
debris.
Attention! After switching to “Economy” mode it is advised to ground balance
the device.
For reference, the detection range in this mode, when air testing a large 43cm
copper coin, such as a Victorian Penny, is approximately 35cm (10” DD coil @ 6,5-7 kHz).
Thanks to the significant reduction in the consumption of power in this mode you
can run up to 40 hours on a set of fully charged batteries.
Switching to the turbo is made through the "Extras” Menu, section “Extra
Settings”"(see below).
MODE S ALGORITHM
From our experience we know that the majority of metal detectors react to flat
iron objects as nonferrous. To assist in solving this problem the specially developed S
algorithm is used to assist in properly identifying these targets.
The most effective use of this algorithm is in identifying small flat iron objects (15
cm2), such as beer caps, rusted pieces roof tin, etc., with a signal rating greater than 10.
If the device detects an object with a "questionable" non-ferrous signal (high
tone) and it has a rating over 10 then using the S-Algorithm can help to identify these type
targets.

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There is no need to use this algorithm for a definitive low-pitched signal, i.e.
when the subject is clearly iron. Remember though, to monitor the signal rating level of
the target.
It should be pointed out that this mode does not apply to general searching, but
only to help clarify the type of metal of a non-ferrous response and to decide on the need
to dig.
The S Algorithm has virtually no effect on the hodograph display of non-ferrous
targets
It should also be noted that when increasing the surface area of iron objects the
effectiveness of the S-algorithm decreases.
To switch to this mode, use the button , the values of the parameters RT
and ST sensitivity and volume should be displayed.
To return to the main search mode press the button again. .
MULTI-FREQUENCY
You may be interested to know that most of the detectors manufactured in the
world will have a comparable sensitivity, for example, a brass disk with a diameter Ø25
mm and copper disc at Ø50 mm, despite the fact that the second object is much larger. It
is also known that small targets (coins) are detected better at higher coil excitation
frequencies.
The fact is that by the virtue of certain physical laws each target class has its own
optimal frequency at which the sensitivity to these targets are maximized. In order to give
the unit the opportunity to search effectively for both large and small targets, many
manufacturers produce 2, 3 or 4-frequency metal detectors. The Signum MFT 7272M
allows you to work with coils with the operating frequencies from 1 to 30 kHz, thus
maintaining acceptable sensitivity to almost any type of target.
The metal detector can be equipped with the following sensors: 15DD -3 (7) kHz,
9.5 x12, 5DD - 7 (3, 14) kHz, 10DD - 7 (3) kHz 6h10DD - 7 (14) KHz.
What could be the practical guidelines for choosing a coil with a different
operating frequency?
3 kHz can be successfully used on non-trashy areas to search for both ferrous and
non-ferrous targets as well as the spoils of war.
7 kHz –Is the average universal frequency for a wide range of applications. You
can search for both medium and small coins as well as the spoils of war. This frequency is
convenient for terrain reconnaissance.
14 kHz - Frequency optimized for small and medium-sized coins especially
when the latter are located on edge. This frequency is the best choice for hunting on the
saltwater beach.

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Селективный металлодетектор «Сигнум MFT» 7272М. Руководство по эксплуатации.
PARAMETER MENU
By pressing the button you have access to a number of additional
parameters, which are divided into 3 groups (Fig. 13). Navigating the menu
Fig. 13
By using the buttons , and
The value in the upper-right corner of the screen indicates the user program
number that you are currently editing.
SEARCH OPTIONS
Conv. Search. [Normal. (Normal), MM (metal trash), AF1 (Filtering algorithm),
AF2, AF3] These options are designed to optimize the operation of the device under
normal conditions, under various degrees of trash within the search area, as well as under
various amounts of electromagnetic interference.
Trashy is defined as an area where the distance between small metal objects (nails)
is 1/2 the diameter of the coil.
To work in these areas use the MM. Otherwise, we recommend you use the mode
"Normal.”
Mode MM is characterized by a fast algorithm for the signal processing, although
there is a nominal loss in sensitivity (30%).
When searching in areas of tall vegetation or in plowed fields with an uneven
surface it is inevitable that bumping of the coil will occur. In these situations, it is
recommended that you use the search modes "AF1, AF2, AF3", where "AF" indicates the
presence of an additional filtering algorithm of the signal. These modes can also be useful
in areas with high levels of electromagnetic interference (EMI). However, it should be
remembered that such filters may slow down the detector process speed. Which AF mode
is best will depend on user experimentation in the local area.
DHR (Discrimination of "hot rocks") [On. / Off.].
This option includes
the ability to suppress the sound response in the (ST) channel to the hot rocks (HR). We
can describe these as rocks with a high ferrous content. Because of the physical features of
the interaction of the Coil with the “HR”, the reaction to them is often confused with the
reaction to large copper or silver coins. This algorithm helps to distinguish between these
two types of responses and to eliminate the audio response to the Hot Rocks.

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Optionally the software can be switched off. The inclusion of DHR is reflected on the screen
in the form of an inscription of "HR" in the upper right-hand corner under the low-battery
indicator. Reaction to these in the RT channel remains.
Attention! The algorithm is turned off automatically in the program
“MM1” and “MM2”
Speed of Auto tracking AGT [off/1 .. 6]. This option allows you to set the speed
limit of the auto tracking of the ground (not to be confused with balancing on a ground).
Auto tracking allows the device to automatically adjust to the slow changes of temperature
and salinity of the soil. It should be noted that this action should in no way replace the
procedure for ground balancing, and only adjusts the balance of soil in small amounts
during the search. In some cases (large amounts of metal trash or a cluster of hot stones)
APB may not work properly. In these circumstances, you should disable the APB.
Attention! If the device has not been used for a long time, for correct operation
of APB it is necessary to ground balance
Gain [1..10] This parameter is used to set the sensitivity of the device in the Real
Time and Identification channels at the same time. In most cases, we recommend that
this value is not set to more than 7. Smaller values can be useful, for example, to search
for large objects that are not deep or in trashy areas.
Shift Frequency [ -5. .. the Central frequency of the device. +5].
This
parameter adjusts the operating frequency shift and is designed to reduce the effect of the
mutual influence of devices operating in close proximity to each other. By adjusting this
parameter, on both instruments, the users can achieve a minimum influence on each other
and improve the comfort of working together at close distances without significant loss of
sensitivity and identification.
For a more effective suppression of the mutual influence of two nearby
detectors it is recommended to spread their operating frequencies.
Always remember that nearby operating instruments can significantly reduce
the search depth.
It is best to choose the level of difference between the operating frequencies
experimentally by setting the distance between the devices and testing the sensitivity of the
devices.
Remember that the detectors must be located in the same plane, which
corresponds to their actual relative position during the search.
Attention! After adjusting the frequency shift of the device remember to perform
the ground balance procedure
DISPLAY SETTINGS
Backlight. Allows you to change the brightness of the screen. The far left light
indicator corresponds to the complete shutdown of the backlight. Remember that too
much backlight level reduces the operating time of the battery life.
Contrast. Sets the desired level of contrast of the display.
Accumulation [1..4]. Option allows you to store the display from 1 to 4
hodograph images simultaneously. Displaying multiple hodographs may be useful, for
example, in the analysis of responses from the same target while scanning from different
angles or directions.