If it's related to METAL DETECTING... It's here in our GLOSSARY!
All the terminology you might encounter as a detectorist, compiled in alphabetical order for your convenience. From technological terms to colloquial slang, we've tried to cover it all!
A kind of technology which continuously measures the level of ground mineralisation when metal detecting. This ensures that the detector is always correctly ground balanced and operating at maximum depth and sensitivity at all times with minimum effort.
When you test your metal detector above the ground, removing the influence of the ground. Used for comparing metal detectors or familiarising yourself with the sounds of your individual detector, but generally regarded to be not the most accurate comparison and often misleading.
The most common non-rechargeable battery composition which has a longer shelf life and can sustain a higher current drain than basic carbon-inc types.
A control setting or found on standard metal detectors. Accepts all kids of metal targets rather than one specific kind.
An electronic circuit or device which is use to increase amplitude or strength of an electronic signal- either an audio or radio signal.
A substance which is composed of two or more different metals or one metal combined with a non-metal. Most alloys are formed when two metals are melted and mixed together as liquids and then left to cool and reform into a solid.
Analogue is a method of data transmitting and receiving between electronic devices or within an electronic circuit. These signals contain information in their amplitude (volts).
A kind of circuitry which enables the operator to make judgements on target conductivity levels, based on sound. Multi-pitch audio responses are produced by a voltage controlled oscillator.
AUTO TUNE (Automatic re-Tuning)
Auto tune is a metal detector feature that shifts the detector’s operating channel in order to reduce the effect of environmental noise. If an environmental noise source is operating at, or producing, harmonic frequencies that match the detector’s operating channel the detector becomes susceptible to falsing. By shifting the detector’s operating channel up or down the detector can avoid being affected by environmental noise.
This refers to false responses on your detector caused by targets that have been rejected being too close or in contact when the detector is operating.
BBS (Broad Band Spectrum)
BBS simultaneously transmits, receives and analyses a broad band of multiple frequencies to deliver substantial detection depth, high sensitivity and accurate discrimination for a wide range of target types. Doing this provides more information than is possible with single frequency technologies, which results in improved target identification accuracy and increased depth. This is particularly useful in environments such as salt water beaches for reducing false signals from the ground minerals.
A bench test is another form of air test used for testing your detector by placing it upon a stationary and non-metallic rest and samples are manually passed across the bottom of the search coil.
BFO (Beat Frequency Oscillation)
BFO is the most basic way to detect metal. There are 2 coils of wire in this system, one in the search head and one in the control box, and each one is connected to an oscillator that generates thousands of pulses of current per second. The pulses travel through each coil and generate radio waves, and a tiny receiver picks up the radio waves and creates an audible series of tones.
This method is often associated with old school detectorists and the earliest of machines.
Black sand is an indicator of negative ground minerals, consisting of the magnetic iron oxide. It can be found either inland or on the beach. It will result in a loss of depth for the detector. However some detectorists believe it is always worth searching as it is denser sand, coins and heavy objects are more likely to sit on top or near the surface.
This set up removes the metal detector control housing from the control shaft and attaches it to the detectorists body by straps or by being fixed onto a belt. The idea behind this is to allow better manoeuvrability and stop your arms from getting so tired! Body mount can also be called hip mount.
A very special once in a lifetime kind of fine!
Butterfly coils are a variant of the DD Search coils' open design with a butterfly like shape.
A cache normally refers to a group of coins, jewellery or treasure which have been buried together- often in a container- although it can also refer to a cluster of coins or objects which have been found near each other, even if not actually in the same hole.
This is the lever which can release or lock the detector's assembly components.
The most basic or standard grade of dry-call battery
Often how detectorists will refer to the sound of a detector which has been badly tuned, a sort of static noise.
A word used to describe a questionable signal, often the sound a detector makes when it finds an object that is almost discriminated out.
A design of search coil which has identical diameter transmit and receive windings stacked and aligned on the same axis. The advantages of this include a uniform detection pattern and resistance to electrical interference up to 60 Hz AC.
COIN DEPTH INDICATOR
This is a meter or a visual display which measures the depth of coins and coin-sized targets in numerical values. However targets which are larger or smaller than the circuitry has been calibrated for will not be able to be measured accurately.
A metal detector enthusiast who looks mainly for coins.
A design of search coil which has two transmit coils (also known as windings) and one receive coil of unequal diameters but aligned on the same centre. These are considered most compatible with the discrimination function. Recent designs have been configured elliptical.
These are the major component of the positive ground matrix. Wet ocean sand can cause false signals in the motion discriminate mode of operation and an increase or positive rise in threshold audio in an unbalanced non-motion all-metal mode.
Conductivity refers to how well a target allows electrical current to flow through it. In other words a highly conductive target has low electrical resistance and therefore allows current to flow more easily. Conversely a target with low conductivity has high electrical resistance and does not allow current to flow easily.
Control house or control box. The part of the metal detector which contains the circuitry, controls, speaker, batteries and the microprocessor.
The front of the control box which houses the display screen and provides access via buttons or knobs to all of the detector's operating functions.
A kind of telescoping metal tube to which the control housing, search coil and isolator are attached. Also called medium shaft.
A configuration for your metal detector where the control housing can be temporarily detached for body-mounting.
The orientation of search coil windings which are occupying the same horizontal plane.
If you detect closely to another hunter, you might suffer from crosstalk. Crosstalk is the interference that is caused by two detectors operating on the same frequency being in close proximity to each other, about 3 to 15 feet distance.
CRYSTAL CONTROLLED OSCILLATOR
An oscillator which utilises a quartz crystal to sustain a stable transmit frequency.
Current is the flow of electrical charge and is measured in Amps. Current measurements are common on batteries and power supplies. Current is also induced into targets by the electromagnetic field produced by metal detectors, these are called eddy currents.
The maximum detection depth achieved by a metal detector. Can vary depending on particular ground-mineral conditions and with a certain search coil. The depth penetration id the detector's depth potential affected by mineralization.
A metal detector's maximum capability to transmit an electromagnetic field with a current search coil without being reduced by ground mineralization and/or improper levels of program settings including ground balance.
DETECTING DEPTH RANGE
Also known as operational depth range. This is the depth penetration that is reduced by high levels of discrimination and/or sensitivity or poor ground balance of a metal detector.
The perceived shape or footprint of effective electromagnetic field transmission directly related to search coil winding configuration.
The term used for a person who is using the metal detector- whether professionally or as a hobby!
A method of reducing the target signal width for accurate pinpointing, by desensitising threshold audio tuning.
Any tool or utensil used to dig for your finds, a trowel, a spade etc.
Digital refers to a method of transmitting and receiving data between electronic devises or within an electronic circuit.
Electronic circuits that process digital signals have many advantages over analogue circuits, including; less susceptible to noise and interference, able to process more information, able to filter signals using less electronic components, are lighter and cheaper.
A variable setting to selectively filter certain metals from being picked up by a metal detector. A high discrimination setting will filter out trash, but also reduces depth. Discrimination is not perfect and may filter out good targets, as well.
By accurately identifying a buried target you can decide to dig it up or consider it as junk and continue searching
DISCRIMINATION PATTERN (Accepted or Rejected)
On a standard detectors display the range of accepted targets is represented by the white area of the conductivity scale and the rejected targets are represented by the black area.
The acceptance of one particular item of certain conductivity, while rejecting other items of the same conductivity but different iron contents. This is a feature of 2-dimensional discriminators which the 1 dimensional discriminators of most regular metal detectors are not capable of doing.
Two positive audio signals which come in rapid succession which are generally associated with elongated ferrous objects such as nails or coins on their edge.
Also known as widescan- this is a search coil design with two "D' shaped windings configured back to back giving it a long and narrow detection pattern from 'toe' to 'heel'. This type of coil is generally employed in high mineral locations where the discriminate function is considered secondary.
Unstable threshold tuning levels caused by temperature extremes, battery strength and rapid changes in mineralization.
When a metal detector has been designed to operate on two frequencies of alternating currents. These kind of metal detectors have little advantage over single-frequency machines as they are not 100% effective in achieving both a good sensitivity to small targets and a good detecting depth.
DVT (Dual Voltage Technology)
DVT transmits two different voltage levels from the search coil. This is advantageous because it improves ground balance, increases sensitivity to small targets and increases operational depth range.
These are small circulating electric currents which are generated when as electromagnetic field contacts the surface of a metal object. Eddy currents flow in closed loops within conductors, in planes perpendicular (at an angle of 90 degrees) to the magnetic field
An electromagnetic field is a classical field produced by moving electric charges. It's force primarily emanates from the top and bottom sides of the coil.
A search coil housing in the shape of an oval containing either the Double D or concentric winding configuration.
EMI (Electromagnetic Interference)
Also known as radio-frequency interference. Refers to a disturbance generated by an external source that affects an electrical circuit by electromagnetic induction, electrostatic coupling or conduction.
Generally received due to objects being either very small or very deeply buried.
These can be caused by loose leads on the coil, stubble, hard soil or junk.
A faraday shield is a metal foil wrapping around the search coil windings used to reduce electrostatic interference caused by contact with wet vegetation on the search coil housing exterior.
FBS (Full Band Spectrum)
FBS is a new technology used by certain detectors, including the Minelab Explorer 2, SE Pro and E-Trac designs. It combines multiple frequency BBS (Broad Band Spectrum) technology with a powerful microprocessor to give greater detecting depth, higher sensitivity, less interference and more accurate identification.
Objects made from or containing iron- if a metal object is attracted to a magnet it is called ferrous.
Often seen as black sand, these are particles of oxidised iron which make up the non-conductive or negative ground mineral matrix.
An outdoor test taken under the real conditions of metal detecting to evaluate your detectors performance and operational characteristics.
FLAG AND BAG
A method used as part of Archaeology surveys usually, where found objects are bagged up and a small flag is left in the spot where they were found.
The Hertz measurement of current cycles in the metal detector.
A feature designed to reduce crosstalk interference by altering the transmit frequency of the metal detector.
Using markers or boundaries to predetermine search areas for metal detecting. This is a great way to ensure you leave no inch of ground uncovered!
Usually Roman or Georgian bronze or copper coins which are worn or corroded.
This is a mode of operation in which the detector has been adjusted to reduce the amount of interference that ground mineralisation has on metal targets, so it can find targets easier.
GROUND BALANCE (Manual)
A ground balance feature requiring manual adjustment by the operator.
GROUND BALANCE (Factory Preset)
A feature which eliminates the ground control and operator manipulation. The metal detector is preset at the factory to an average range of non-conductive soils.
GROUND BALANCE (Self-adjusting)
An automated ground balancing feature, where the detector circuitry senses change in mineralisation and compensates to sustain balance.
The ability of the detector to compensate for the effects of ground mineralisation.
This can be positive or negative mineralisation in the ground causing a loss of depth on the detector.
Specialised sections of metal detector circuitry which separate the ground mineral effect from metal responses in the motion discriminate mode. Quality of design dictates the level of efficiency, sweep rate, depth penetration and recovery time related to target separation.
The "halo effect" theory states that buried metal objects have an ionization "halo" that increases their apparent size to a metal detector searchcoil. This makes the objects detectable at a greater depth. So according to this theory, long-buried metal objects have something you cannot duplicate with recently or shallow buried objects.
A sort of slang term used by detectorists to describe a site which has already been searched many times. Also known as searched out, hunted out and pounded site.
Used to block out other noises and distractions and to enhance the detectorist's hearing capabilities, and also preserves the machine's battery length over using it's speakers.
A temporary condition which affects detectorists where their brain's ability to process the incoming sounds decreases. This happens either when a lot of audio tones come in all at once or in a non-stop manner, or if the detectorist has been out hunting for a long period of time without a break.
The southern section of search coil behind the control shaft attachment point as viewed from above by the operator.
Measurement of cycles per second.
A collection of valuable items, often coins, which have been buried for safe keeping but never retrieved.
A hot rock can loosely be defined as: any rock or stone not containing a valuable mineral (gold, silver, or copper) which generates an audible signal response on a metal detector. Basically they contain more nonconductive or conductive minerals than the surrounding ground to which the metal detector is balanced.
IB (Induction Balance)
A condition of zero current flow between transmit and receive windings prior to metal detection, used in the most common detectors these days.
The electrical property of a metal target to oppose variations of the magnetic field. This characteristic is sometimes referred to as Ferrous Content.
The lower most section of the non-metallic control shaft which attaches to the search coil and separates the metallic portion of the control shaft from the electromagnetic field. Also known as the lower shaft.
Another slang word often used by detectorists, describes a good metal detecting find.
1000 cycles per second.
LCD (Liquid Crystal Display)
The basis for metal detector visual graphic display technology.
LED (Light Emitting Diode)
A lamp-like semiconductor used for visually indicating circuit functions such as target response and battery condition.
Using a high powered magnet on a line to pull ferrous objects from the bottom of a creek or lake. A common “side-hobby” of detectorists.
When a piece of iron is next to a desirable target and alters the way the detector responds. Could also describe a mode on a metal detector which temporarily removes all/part of discriminating
The total volume of ground penetrated by the electromagnetic transmit field containing minerals, metals, salts, rocks, moisture and organic matter.
This refers to soil which contains non-conductive or conductive properties which directly influence metal detector tuning and depth penetration.
MINERALIZATION (Natural Magnetic, Sporadic, Littoral)
The amount of non-conductive or conductive properties in either soil or sand. Can be:
Natural magnetic- iron oxide, hot rocks and magnetite.
Sporadic- (this is also magnetic) at sites of former human settlements, pottery, slag, bricks, heaths and hot rocks.
Littoral- at the seashore. Properties of this mineralisation can range from magnetic (black sand) to electrically conductive (salt water) depending on the beach or region.
The state selected by the operator on the metal detector to complete a specific task.
A configuration for your metal detector in which the circuit boar can be easily removed or replaced if needed to be repaired or upgraded without replacing the entire metal detector.
A type of search coil which has multiple strands of wire wound in a single loop around the coil circumference. These provided greater depth and sensitivity in soil with low to medium mineral content.
A detector which requires constant search coil motion to reduce the effect of ground mineral interference on it's discriminate function.
MOTION GROUND CONTROL
Where movement of a search coil is required for controlling the ground mineralisation.
Technology such as BBS and FBS used by Minelab detectors, which employ multiple transmit frequencies to enhance the separation of ground mineral effect from target response to increase target identification accuracy.
MULTI PERIOD SENSING (MPS)
Pulse induction technology patented by Minelab. Uses varying pulse widths to extract more information from targets, achieve better ground balance and detect to greater depths.
An audio target signal which is not wider than the search coil.
A non-conductive soil matrix which has a nulling or negative effect on an air tuned audio threshold.
Soil which has neither conductive or non-conductive properties.
A type of rechargeable battery. Nickel-Cadmium.
When a coin or object has been hit or damaged by your digging tool.
Slang used to describe somebody who detects illegally at night.
A kind of rechargeable batteries which have a nickel-metal-hydrate composition. They have a longer life span and are not affected by memory to the same degree.
Metal types which do not contain iron, such a gold, silver, copper, aluminium etc. These metal types will not be attracted to a magnet.
Any operational mode which does not need search coil motion to sustain target response. These were first developed in the 1960's and need to be manually tuned and retuned every few minutes due to the signal drifting.
As above, but movement is not required of the search coil to get an audio response from any metallic target. Useful mode for pinpointing targets.
A basic mode which eliminates all responses except those whose conductive properties fall within the range of the notch width.
This allows us to select which one of the conductivity segments in the discrimination scale are active or disabled. If a segment has been 'notched out' then metals within that range of conductivity will be masked and will not produce a signal.
NOTCH FILTER DISCRIMINATION
A specialised discrimination circuitry which selectively accepts or rejects a narrow conductive range of targets inside or outside of normal discrimination settings. An example of this could be accepting nickel coins while rejecting targets higher in conductivity such as pull-tabs.
The control which is used to position the notch width or window within the range of metallic conductivities.
A basic mode of discrimination which rejects only targets whose conductivities fall within the range of the notch width.
A range of conductivity, which can be adjustable or preset, and is positioned by the notch level setting.
When the metal detector threshold audio disappears- often because of a large quantity of iron, a hot rock or a rejected target.
A person who specialises in the study and collection of coins and currency.
A metal detector circuit component which sends a specific current frequency generation to the transmit windings of the search coil to produce an electromagnetic field.
A walking pattern where you overlap the last pass slightly for good coverage.
When there is too much metal under the coil for the machine to be useful.
False signals produced by an auto-tuned non-motion discriminate mode as the search coil passes too quickly past a rejected target. Excessive audio restoration by automatic re-tuning produces these false signals outside the target response periphery.
A high pitched sound at a high depth.
The time passed between the target surface eddy current generation and resulting secondary electromagnetic field effect on the search coil's receive windings. Also called phase lag or phase angel and is directly related to target conductivity.
The process of reducing the target to a smaller area in which to dig. Most metal detectors have a pinpointing mode which allows
The area that has been left relatively undisturbed in agricultural fields as it is deeper than plows can reach.
A hole which has been carefully dug in the ground so that the dirt and grass are not harmed. It is considered the mark of an experienced and ethical metal detectorist to dig a good plug, as it reduced the impact on the area being hunted.
A bunch of coins which has been lost from ones' pocket or purse, often found in highly populated areas where people have been sitting down.
A small tool which resembles an ice pick, often made of brass, used to locate coins before digging by touch.
Soil which contains conductive minerals or wet salts that affect an air tuned audio threshold.
PRESET FACTORY PROGRAMS
A number of search programs which have been designed and incorporated into the metal detector's memory to make it easy to begin using the machine straight out of the box. Programs could include 'coins' 'jewellery' 'relics' 'beach' etc
PI (PULSE INDUCTION)
Pulse induction circuit technology. This type of detector ignores both conductive and non-conductive minerals simultaneously by pulsing the receiver amplifier off before the response from wetted salts and iron oxides can reach the search coil winding.
PUMPING MODEA semi-automatic or manual process which allows an operator to adjust the metal detector's ground balance in a zone that has been determined to be representative of the mean level of ground mineralisation in the area being searched.
The length of time it takes between metal sensing and getting an audio/visual response.
Inside the search coil house there is a coil of wire whose function is to accept the secondary electromagnetic field generated on a target's surface by eddy currents.
This is how long it takes a metal detector to respond to a new target after responding to a previous target. This could also be called reactivity or recovery speed. The best coin shooting metal detectors have high reactivity levels of around 2 or higher, but most metal detectors have slow recovery speeds between 1 and 1.5, meaning they are often unable to respond to all targets in close proximity.
This is when a metal detector is being operated in the discriminate mode and it does not accept a target, indicated by a null in threshold audio.
Metal detecting enthusiasts who search for more common objects and not just precious metals. Often take part in searches in fields or woods, with finds hailing from early conflicts such as the Civil War in the US.
The term used to describe the groved edge of many silver coins- the opposite of a smooth edge. A reeded edge is often the first clue of the type of coin found in the ground.
When you manually retune the threshold audio via an external switch.
Rusted beyond all recognition.
This is the electromagnetic field which is received back by the coil and is used by the control box circuitry to process it accordingly.
A control shaft fro metal detectors which is designed with offsets which increase the operators comfort by reducing the amount of fatigue to the arms and wrists.
To complete a detection oath of search coil travel or sweep.
A super high quality signal that is loud in the headphones.
The housing which holds the transmitter and receiver windings or loops, which are aligned in a specific configuration. Examples include coaxial, co-planar, concentric and double D. Sometimes also known as a search loop.
SEARCH COIL CABLE
A cable of electrostatically shielded wires which carries circuit board oscillator current frequency to the search coil and phase related target information back to the control housing.
A hunt where the the finds have been scattered or planted.
The measure of a metal detector's ability to detect a specific type and size of metal contaminant. A better sensitivity means the capacity to detect smaller and irregular shaped bits of metal.
The audio or visual response emitted by a metal detector, which alerts the operator to the discovery of a metal object.
This is also known as silent search, and refers to a search mode which does not use constant threshold audio tuning in order to maintain sensitivity.
This is a kind of metal detector which is designed to operate on only one frequency of alternating current. Most detectors on the market operate on a single frequency, and although this has served the industry well for years, scientists have now found that a frequency that worked well in one are will often only offer a marginal performance when used in another location. Things that effect how well a single frequency detector works include ground mineralisation and target size.
SKID PLATE (Coil Cover)
This is a non-metallic cover which is placed on the search coil bottom for protection against abrasion.
The measure of time associated with metal sensing and peak audio or response, which is generally associated with PI type detectors.
A coin that is highly worn, often making it difficult to see it's details.
A signal that sounds like a squeak, often produced by coins on their edge.
The quality of a metal detector circuit to resist external sources of thermal and electrical interference.
This is a feature which is designed to eliminate the response from discrimination targets lying within a predetermined depth. It is based on signal intensities usually associated with shallow depths.
The width and/or speed rate of search coil scan.
Moving the detector coil side-to-side during a hunt.
Any hidden or buried object to which a metal detector responds.
The ability of a metal detector to respond to individual targets within a closely spaced group.
The ability of a metal detector to respond to individual targets within a closely spaced group.
Any control (for example ground balance) which requires ten revolutions of the indicator knob to cover the adjustment range of it's function.
A plot which has a bunch of targets intentionally buried by a detectorist. This kind of controlled environment is useful for comparing metal detector performances and often the coins have been arranged by size depth and composition.
The minimum audio level of tuning adjusted for optimum sensitivity. If you are not operating in silent mode, the threshold is heard as constant background humming during detecting. This is why it is important to keep the threshold to a minimum audio level to enable you to hear small and deep targets.
TH'ER (TREASURE HUNTER)
TH'er is an abbreviation for Treasure Hunter and refers to an enthusiast in a hobby of metal detecting and treasure hunting. Often also known a a Detectorist.
A coin that is badly corroded because of a long period of time in the ground.
The northern section of search coil above the control shaft attachment point as viewed from above by the operator.
An adjustment used to regulate the audio frequency or sound pitch to operator preference used to contrast target response with external ambience.
Different sounds identifying different target’s sounds on many modern detectors. High tones usually indicate high-conductivity targets such as silver or copper, while low-tones are for low-conductivity targets such as gold.
A metal detector that requires you to learn the sounds rather than looking at the display to successfully classify what you’ve found before digging.
A linear 'lane' of detecting in a broader grid, often associated with Archaeology.
The process of sending a signal or magnetic field from the metal detector's search coil.
This is the coil of wire which generates and transmits the primary electromagnetic field from within the search coil housing into the soil matrix.
This is a class of metal detectors which operate in a broad range of radio frequencies. These detectors can tell the difference between a ferrous and a non ferrous object, but they do not have enough depth in highly mineralised ground. TR detectors are more or less obsolete now.
This is an automatic mode of metal detector, in which the detector continually scans the ground and digitally filters the recieved responses to determine the mean value of mineralisation in the soil and automatically readjusts the ground balance. This may be useful in soils with relatively uniform mineralization.
This is a kind of metal detector which automatically eliminates the ground mineralisation while in operation.
VCO (Voltage Controlled Oscillator)
This is a kind of oscillator circuitry driven by target voltage to produce varying audio pitch or visual display responses for target identification and pinpointing.
Technology that uses state of the art digital electronics to improve on the standard single frequency detection technology. Advantages of this include a dependable performance and improved immunity to outside interference, as well as being able to change the frequency of the detector by simply changing the coil which is being used.
A location which has not been metal detected before.
A feature of metal detectors which provides the operator with a probable target identification. Indications are either a metered needle movement or a LCD display.
VLF (Very Low Frequency)
A VLF metal detector consists of a coil of wire, which has electricity running through it in one direction and then the other at a rate of thousands of times each second. The rate at which the electric current passing through it is reversed determines the operating frequency of the transmitter coil.
A class of metal detector of transmitter/receiver type which operates in the very low frequency range.
The electrical potential, measured in volts. Common measurement on batteries and power supplies.
The control on a metal detector which regulates the loudness of the target response.
An audio target response associated with an all-metal non-motion mode which is wider than the physical size of the search coil.
Any search coil capable of producing a target response across it's full dimension.
WIRELESS HEADPHONE OPERATION
When headphones are not connected to the metal detector by a cable, instead signals are received from a transmitter that is incorporated into the detector.
WIRELESS METAL DETECTOR
A metal detector which is fully wireless, including wireless headphones and search coils. Data is sent via a digital radio link rather than through a cable which greatly improves data quality and increases the operational depth range.
As All-metal, this is a discrimination control characteristic which accepts ferrous metals at it's minimum setting.