AC
(Alternating
Current)-
Metal detector
modes that require loop motion to respond to metal.
Air Test-
Testing a metal
detector's response to various metallic samples with the
loop held away from the
ground.
All-Metal-
Describes any mode
or control setting allowing total acceptance of all types of
metal targets,
iron and non-iron.
Audio Identification-
Circuitry or mode
producing different audio tones (pitches) for different
target types.
AutoTrac (Automatic Ground Tracking)- A feature that continually and automatically
readjusts the ground
balance (ground rejection) of a metal detector during
searching.
Back Reading-
A false target
response caused by either overloading due to a very strong
target near the
loop, or a rejected trash target very close to the loop.
Black Sand-
One of the most
extreme components of nonconducting negative ground
mineralization. Also called
(Fe304), magnetite, iron oxide, magnetic sand.
Cache-
Intentionally buried
or secreted hoard of valuables.
Conductive Salts-
One of the major
mineral types which makes up the positive ground matrix. Wet
ocean salt/sand
will produce a positive indication much like a metal target.
Conductivity-
The measure of eddy
currents of electricity that generate on a metals surface.
Custom Program-
Feature choices on
a computerized metal detector that are then saved or stored
for future use.
DC (Direct Current)-
Used to refer to
metal detector modes that do not require loop motion to
respond to metal
targets.
Detection Pattern-
The shape of the
electromagnetic detection field generated by a metal
detector's loop.
De-tuning-
A method of
narrowing a target signal's width and length for precise
pinpointing.
Depth-
How deep a detector
can respond to metal targets.
Depth Reading-
Feature that
indicates how deep a target is in the ground before digging.
Discrimination-
Adjustable feature
that can ignore or respond to different metal types based on
their amplitude
and phase. Used to cancel responses of unwanted trash
metals.
Drift-
A loss or increase
in threshold caused by the passage of time or variations in
temperature..
Eddy Currents-
Small circulating
currents of electricity on the surface of metals produced by
external electromagnetic
fields.
Electromagnetic Field-
An invisible force
extending from the loop created by the flow of alternating
oscillator frequency
current around the transmit winding.
Elliptical Coil-
A loop with an
ellipse (oval) shape.
False Signal-
Erroneous signal
caused by non-metal items.
Faraday Shield-
Conductive coating
inside loops, loop cables, and control housings to eliminate
electrostatic
interference.
Ferrous Oxide-
Decomposed
particles of iron (mineralization).
Frequency-
The number of
complete alternating current cycles produced by the transmit
oscillator per
second. Measured in Hertz (Hz) or cycles per second.
Frequency Shift-
Changes the
operating frequency suppressing the interference (cross
talk) between
detectors.
Fringe Target-
A target so deep or
so small as to be barely detectable with a metal detector.
Ground Balance-
A feature that can
be adjusted to ignore the masking effect ground minerals
have over metal
targets.
Ground Matrix-
Total volume of
undisturbed ground, usually contains varying amounts and
combinations of
minerals, moisture, and salt. In an undisturbed condition
the ground matrix can
exhibit numerous phenomenons regarding metal detector
performance.
Hipmount-
A configuration
where the control box of a metal detector is mounted on the
operators hip
limiting the weight one has to sweep to that of the loop and
rod assembly.
Hot Rock-
A rock that
contains a higher concentration of minerals than the
surrounding ground.
Interference-
Hinderance of
performance due to sources outside a metal detector causing
static and unwanted
or false signals.
LCD (Liquid Crystal Display)- A digital display used for graphic visual
indications as an
alternative to the use of meters.
Memory-
A computerized
metal detector's ability to retain operator selected
settings for future use.
Menu-
A display screen
that allows the operator to choose among different features.
Meter-
An analog component
which provides visual indications regarding a metal target
(Alternative to LCD
displays).
Mineralized Ground-
Any soil or sand
that contains conductive and/or magnetic components
(minerals).
Mixed Mode-
A special metal
detector mode that combines all metal and discriminate
features into one
operating mode.
Mode-
A condition or
feature of operation selected by the operator for specific
functions.
Motion Instrument-
A detector type
that requires search loop movement to activate the signal
from a metal target.
Microprocessor-
An electronic
component (chip) that can be programmed to perform a variety
of functions and
control a variety of features.
Negative Ground-
Soil containing
mostly magnetic minerals.
Neutral Ground-
Soil that contains
no significant minerals.
Nicad (Nical Cadmium)-
A battery type that
can be recharged.
Non-Ferrous-
Not of iron .
Metals of the precious and semi precious class (i.e.
aluminum, brass, lead,
gold, silver, copper).
Non-Motion-
Mode that will
respond to metals with or without movement of the loop.
Notch Discrimination-
Discrimination
circuitry that allows an area of the discrimination range to
be accepted or
rejected independently of the remaining discrimination range
(a window of
acceptance or rejection within the discriminate range).
Notch Width-
Finite range of a
notch discrimination setting (how wide of window is accepted
or rejected).
Null-
A decrease in sound
caused by rejection of targets or ground mineralization.
Oscillator-
An electronic
component or circuitry designed to generate a specific rate
of current
frequency to power the loop's transmit winding.
Overlap-
Advancing each
sweep of the loop in small increments to insure good area
coverage. Each sweep
should overlap the last by at least 50%.
Overload-
Occurs when the
receiver of a metal detector becomes overwhelmed due to too
much signal (ground
and/or target).
Overshoot-
A false signal
heard as the loop passes over a rejected target when using a
non-motion
discriminate mode in combination with automatic tuning.
Excessive tuning
restoration pushes the audio above the threshold level
creating a positive
response at the edges of target detection.
Phase-
The length of time
between eddy current generation sustained on a metals
surface and the resultant
secondary electromagnetic field effect on the loops receive
winding. Relates to
target conductivity.
Pinpointing-
Finding the exact
target location with respect to the loops physical center.
PI (Pulse Induction)-
A type of metal
detector circuitry that operates differently than the
standard Transmit Receive
or Very Low Frequency instruments. Primarily recommended for
better results in
salt water.
Positive Ground-
Soils that contain
conductive components such as salt.
Preset-
A control setting
or marking determined to work well for average conditions.
Preset Program-
A selection of a
computerized metal detector that automatically selects all
the features suited
to a particular type of searching condition.
Prospecting-
Searching for gold
in its natural state (nuggets).
Rejection-
Non-acceptance or
cancellation of a target response by discrimination
circuitry.
Relic-
An artifact of the
past.
S.A.T. (Self Adjusting Threshold)- Automatically resets the threshold to correct for
any minor ground,
temperature, or electrical changes that typically cause
threshold variations.
Scrubbing-
Sweeping the loop
with contact to the ground.
Searchcoil-
(See Loop)
Sensitivity-
Measure of a
detector's ability to respond to targets within the
detection pattern. Usually
indicates the capability to respond to small targets rather
than maximum
detection depth.
Signagraph-
A graphic display
of a pattern characterizing a targets electrical and/or
magnetic properties.
Signal-
An audio response
or visual indication alerting the operator that a metal
target has been
detected.
Silent Search-
Capability of a
metal detector to respond to metals without a threshold or
background sound
being heard continually during searching.
Stability-
The ability of a
metal detector to maintain smooth operation without
interference or unstable
operation.
Target-
Any object that
causes a metal detector to respond.
Target Masking-
When large size or
high concentrations of trash metals, or extreme ground
mineralization, drive
the threshold into the null zone suppressing weaker positive
responses.
Ten-Turn Control-
A control knob
which can be rotated ten times to cover the full electrical
range of the
feature.
Test Garden-
A mapped plot of
buried targets at various depths to aid in learning the
characteristics of a
metal detector.
TH'er, TH'ing-
Universal word
contractions for treasure hunter and treasure hunting.
Threshold-
The background hum
heard continually during the use of a metal detector
indicating the most
sensitive audio.
Tone Control-
An adjustment for
audio frequency or pitch.
Touch-Pad-
Switches
encapsulated in plastic or that allows the operator to
select different
functions or features.
Transmit Coil-
A coil of wire
inside the loop that creates the primary electromagnetic
field.
TR (Transmit Receive)-
Term used to
describe early metal detector technology. Usually describes
non-ground
rejecting detectors or modes.
Two Box-
A metal detector
that has the transmit and receive coils mounted in separate
housings. By
enlarging and separating the transmit and receive coils
great depths regarding
large metal items can be achieved. Also called cache
detectors.
Viewing Angle-
A liquid crystals
display adjustment for contrast allowing optimum visibility
for various light
conditions.
Visual Discrimination-
The ability of a
metal detector to determine trash or non-trash by means of
visual indications.
Visual Discrimination Indication (VDI)- A visual indication as to the type of target a
metal detector is
detecting.
VLF (Very Low Frequency)-
Generally used to
refer to metal detectors that can cancel the effects of
ground mineralization,
typically with operating frequencies in the 3-30 kHz range.
VLF/DISC-
A detector that can
cancel ground mineralization while at the same time
discriminate against trash.
Voltage Regulator-
Circuitry that
controls the amount of electricity supplied to operate a
metal detector with no
loss in performance over a specific voltage/current range.
Zero Discrimination-
Used to describe
detectors whose discrimination control allows the acceptance
of all types of
metals when set to the zero position.