Glossary of Metal Detecting Terms

Terminology Used Among Metaldetectorists & in Metal Detector Instruction Manuals: from S to Z

S

"S" HANDLE - A metal detector control shaft designed with offsets which increase operator comfort by reducing arm and wrist fatigue.

SCAN - To complete a detection path of search coil travel or sweep.

SEARCH COIL - The search head or housing which holds both transmitter and receiver windings (loops) aligned in a specific configuration, (see COAXIAL; CO-PLANAR; CONCENTRIC; DOUBLE D) Also known as a search loop or coil.

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.

SENSITIVITY - The measure of a metal detector's capacity to sense changes in conductivity throughout the pattern of detection set forth by the search coil configuration, (see AIR TEST).

SIGNAL - A visual and/or audio response which alerts the operator to the presence of a metal object (see FALSE SIGNAL).

SIGNAL WIDTH - The ground distance measure of search coil travel in which target audio is sustained. Signal width is directly proportional to target size and ferrous content when operating in a non-motion all-metal mode.

SILENT OPERATION - A search mode which does not use constant threshold audio tuning to maintain sensitivity. Also called SILENT SEARCH.

SINGLE-FREQUENCY (see also FREQUENCY) - This is when a metal detector is designed to operate on one frequency of alternating current which is generated by the transmit oscillator and passed through the transmitter coil. Most detectors on the market operate on a single frequency, ranging from 1 to 70 kilohertz (kHz). Although this technology has served the industry well for years, the scientists found that a frequency that worked well in one area would often offer only marginal performance when used in another location. Ground mineralization, trash content, and target size all have an effect on how effective a detector transmitting a single frequency would operate.

SKID PLATE (Coil Cover) - A non-metallic cover placed on the search coil bottom for protection against abrasion.

SLOW MOTION - The rate or class of search coil sweep speed necessary to efficiently operate the motion discriminate mode.

SLOW RESPONSE - The measure of time associated with metal sensing and peak audio/ visual response. Generally associated with PI type detectors.

STABILITY - The quality of a metal detector circuit to resist external sources of thermal and electrical interference, (see DRIFT).

SURFACE BLANKING - A feature designed to eliminate the response from non discriminated targets lying within a predetermined depth. Based on signal intensities usually associated with shallow depths.

SWEEP - The width and/or speed rate of search coil scan.

T

TARGET - Any buried or hidden object to which a metal detector responds.

TARGET MASKING - The overriding or interfering effects large or numerous rejected targets have over desirable targets in close proximity.

TARGET SEPARATION - The ability of a metal detector to respond to individual targets within a closely spaced group.

TEN-TURN - Any control requiring ten revolutions of the indicator knob to cover the adjustment range of its function, (i.e. ground balance).

TEST GARDEN - A plot of targets intentionally buried by the detectorist. Arranged by size, depth, and composition for learning characteristic responses and comparing metal detector performances in a controlled environment.

THRESHOLD - The minimum audio level of tuning adjusted for optimum sensitivity. If your metal detector is not operated in Silent Search mode, the Threshold is heard as constant background "humming" during detecting. Threshold should be adjusted to a minimum audible level, so you can hear very small and deep targets. When a rejected target is detected, the Threshold sounds "blanks" or "null" (becomes silent) indicating that an undesired target is underneath the search coil. Threshold can be set anywhere between "no sound" (silent) and loud.

TH'er - An abbreviation for Treasure Hunter, an enthusiast in a hobby of metal detecting and treasure hunting. Also called a Metaldetectorist or Detectorist.

TOE - The northern section of search coil above the control shaft attachment point as viewed from above by the operator.

TONE CONTROL - An adjustment used to regulate the audio frequency or sound pitch to operator preference. Also used to contrast target response with external ambience.

TONE ID - Audio identification of a target based on a principle of relationship between the target's conductivity and the tone's pitch: the higher the conductivity, the higher the tone, i.e. the lowest pitch tone for iron, the highest pitch tone for silver.

TRANSMIT WINDING - The coil of wire which generates and transmits the primary electromagnetic field from within the search coil housing into the soil matrix.

TR (Transmitter/Receiver) - A class of metal detectors operating in a broad range of radio frequencies (i.e. VLF/TR; VF/TR) utilizing the inductive balance principle of metal detection. TR detectors are able to tell the difference between a ferrous and nonferrous object, but do not have enough depth in highly mineralized ground. TR detectors are obsolete now.

TRACKING MODE - an automatic mode of a metal detector, in which the detector continually scans the ground and digitally filters the received responses to determine the mean value of mineralization in soil and automatically readjusts the ground balance. This mode may be useful in soils with relatively uniform mineralization.

TURN-ON-AND-GO - A type of metal detectors that automatically eliminate the ground mineralization while in operation. This is achieved by the Automatic Ground Balance feature also called Automatic Ground Compensation, Auto Tune, etc., depending on a metal detector. Using a metal detector of this type, an operator does not have to manually adjust the detector's ground balance before or during the detecting process.

V

VCO (Voltage Controlled Oscillator) - Oscillator circuitry which is driven by target voltage to produce varying audio pitch and/or visual display responses for target identification and pinpointing.

VFLEX Technology uses state of the art digital electronics to enhance standard single frequency detection technology. This has the advantage of providing dependable performance and improved immunity to outside interference. VFLEX technology also has an added advantage of being able to change the frequency of the detector by simply changing the coil being used.

VISUAL ID - A metal detector feature which provides the operator with a probable target identity reference in terms of relative conductivity. Indications can be a metered needle movement or LCD display.

VLF - Very Low Frequency (see also FREQUENCY). Metal detector of this technology uses two coils - a transmitter (outer loop) and a receiver (inner loop), that are encompassed inside the detector's search coil. Alternating current is passed through the transmitter coil, with the frequency corresponding to the number of times per second that the current changes direction. This current generates a magnetic field which will cause any conductive objects in range to generate magnetic fields in the opposite direction of the transmitter's magnetic field. The "receiver" coil receives frequencies or data that come or "bounce" back from the targets detected and relays the signals to the control box, which interprets the signal for depth and type of metal.

VLF/TR - A metal detector class designation meaning a transmitter/receiver type detector operating in the very low frequency range. This technology represents a combination of Very Low Frequency and Transmitter/Receiver technologies thus enabling the VLF/TR detectors to control trash and ground mineralization simultaneously.

VOLUME CONTROL - A metal detector control which regulates the loudness of target response.

W

WIDE RESPONSE - An audio target response associated with an all-metal non-motion mode which is wider than the physical size of the search coil.

WIDE SCAN - A description of any search coil capable of producing a target response across its full dimension.

WIRELESS HEADPHONE OPERATION - Headphones are not connected to a metal detector by a cable. Instead, the headphones receive signals without a delay from a transmitter that is incorporated into the detector. Metal detectors of the XP Metal Detectors (GoldMaxx Power and Deus), White's (Spectra V3) and Minelab (CTX 3030) manufacturers utilize wireless headphone operation.

WIRELESS METAL DETECTOR - A fully wireless metal detector that has wireless headphones and search coils. An ultra-miniature electronic circuit, incorporated into the search coil, digitizes and analyzes responses from the detected targets. Data is then sent to both the headphones and a remote control (if it is used) via a digital radio link. With this method, the signals are processed at source and not conveyed through a cable, which greatly improves data quality and increases the metal detector's operational depth range. The XP Metal Detectors company (France) pioneered in this technology introducing a fully wireless metal detector - XP Deus, to the market in 2009.

Z

ZERO DISCRIMINATION - Describes a discrimination control characteristic which accepts ferrous metals at its minimum setting, (see ALL-METAL).



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