They are bombarded with terms like, Audio Response - All Metal - Concentric - Detuning - Discrimination - False Signal ( or falseing ) - Frequency Shift - Ground Balance - No-Motion - Null , and a host of other alien terms seemingly designed to confound the newcomer.

Well, this month I hope to list and clarify some of these alien terms so that the newcomers ( and maybe a few not so newcomers ) can understand what experienced detectorists are talking about and better understand the hobby they have just entered or are about to enter.

AIR TEST AND BENCH TEST- A procedure performed by placing the detector on a non-conductive surface and passing various sized metal objects beneath the searchcoil to check the detector’s target response, target ID, depth, the coil’s area of detection, and at what approximate discriminate settings various metal samples are rejected or accepted.

ALL METAL - A separate mode on the detector that allows total acceptance of any type of metal sans any discrimination. This usually works in conjunction with the Ground Balance feature.

AUTO TUNE - A feature that continuously retunes the detector threshold to the original manually tuned audio level.

BACK SHOOT - Caused by slightly tipping the outside edge of the coil up at the end of your scan ( detuning the coil ). Often, users mistake this for a defect in the detector or falseing.

BLACK SAND - Known as magnetite or magnetic iron oxide, and one of the most extreme nonconductive, negative ground minerals. Found mostly in gold bearing areas and sandy beaches.

CACHE - A secret hoard of money, jewels, gold, valuables, intentionally buried.

COIL - A circular or various shaped plastic housing containing the transmit and receive windings ( wire coils ), either single or multiple in a special configuration. Also called head, loop, searchcoil. Emits and receives signals to and from the ground and any metal target.

CONCENTRIC - A coil using one or more transmit and receive windings having unequal diameters aligned on a common center. Coplanar concentric , if arranged on the same level or plane.

CONDUCTIVITY - The manner in which a metal target allows eddy currents to generate on its surface.

DETUNING - method of narrowing the target signal width manually for precise pinpointing by adjusting audio threshold into the null or less sensitive tuning zone. Accomplished by releasing and pressing the pinpoint control one or more times while the coil is over the target.

DISCRIMINATION - An adjustable control and method by which a detector tells one metal target from another, ignoring or nulling audio responses from a specific conductivity range. This allows positive responses to be heard from metal higher on the conductive scale above the discrimination control setting, and eliminating responses from lower conductive trash.

DOUBLE-D, 2D, or WIDE SCAN COIL - A searchcoil capable of detecting a target across at least its full diameter. It is a coplanar coil with two “D” shaped windings positioned back to back and overlapping each other.

FAINT SIGNAL - A small or deep target that barely produces an audio response.

FALSEING, FALSE SIGNAL or BACK READING - When in the discriminate mode, a signal caused by a rejected target coming within one inch of or contacting the coil bottom. A false signal created by overshoot, backshoot, uneven ground, or highly mineralized hot rocks.

FERROUS - Any iron or iron bearing mineral.

FREQUENCY - The number of alternating current cycles produced by the transmit oscillator per second, measured in KHZ or cycles per second.

FREQUENCY SHIFT - A feature which eliminates the cross talk between two detectors working side by side operating on identical transmit frequencies.

GROUND BALANCE - A detector’s ability to ignore the masking and disruptive affects that iron ground minerals have over targets. Similar to fog lights penetrating heavy fog.

HALO - This is generated over time by the combination of acids and water in the soil leaching minute particles off a coin and into the surrounding soil creating a metallic halo around the coin.

HOT ROCK - Rock that contains a higher concentration of nonconductive ground minerals than the surrounding ground that the detector is balanced to causing the detector to signal as if over a good target in motion and non-motion modes and a null in threshold in the all metal, ground balanced mode. ALSO IRONSTONE - A rock heavily laced with iron.

MATRIX - The total volume of ground penetrated by the electromagnetic field transmitted by the coil.

METAL DETECTORIST - A person who operates a metal detector. Other names are, TH’er, or beeper swinger.

MINERALIZATION - Conductive or nonconductive components found in the soil.

MODE - The operating settings you select on your detector, such as all metal.

NARROW OR TIGHT RESPONSE - A target that produces a signal so short that pinpointing is almost unnecessary.

NON-FERROUS - Metals not made of iron, such as gold, silver, copper, etc.

NOTCH DISCRIMINATION - A circuitry that allows a “window’ of good targets to be accepted within the rejection range of unwanted targets, such as rejecting pulltabs, foil, nails while accepting gold rings and nickels of the same conductivity. Can also be set to accept a specific target while rejecting all others or vice versa.

NULL - In metal detector tuning, the zone just below audible threshold. Also, the momentary silent response of threshold audio as the searchcoil scans over a discriminated or rejected target.

PINPOINTING - Centering the target under the coil by interpreting the exact spot of loudest audio response from both directions.

PI or PULSE INDUCTION - A detector with a transmitter circuit that pulses an electrical current into the ground just before it shuts down. Metals hold the eddy currents because they are better conductors while the currents quickly dissipate from poor conductors such as ground

minerals or wet salt sand. The receiver circuit then comes on and picks up the signal from metal while the eddy currents in the ground minerals have quickly disappeared.

SCAN or SWEEP - The procedure of passing the searchcoil back and forth over the ground.

SCRUBBING - Pressing the searchcoil tight against the ground as you scan to maintain even audio threshold and gain more depth.

SENSITIVITY - The ability of a detector to sense changes in conductivity within the signal pattern or making the coil more sensitive to the targets you are seeking. The more sensitivity you can use the greater depth you will achieve.

TARGET - Any object that generates an audio or visual response from your detector.

TARGET MASKING - Basically when junk or concentrations of junk hide or suppress a response from a good or small target from the searchcoil’s signal.

TEN-TURN - A control used with manual ground balance that can be turned ten times to cover the full electrical range of the function and balance the coil to the ground. In some ways like the fine tuner on an FM radio.

TEST GARDEN - A plot of ground in which one buries various targets at different depths to check and learn about the performance of a detector in regards to depth, discrimination, target responses, etc. Caution: Due to an effect known as “ Metallurgical Phenomenon” newly buried coins are difficult to detect, so if you bury them deep don’t plan on locating them for some time until they have had time to react with the acids in the soil and form a halo.

TH’er or TH’ing - Word contractions for treasure hunter and treasure hunting.

THRESHOLD - Probably the most misunderstood term in metal detecting. It is a continuous tone that establishes the lowest sound level for deep targets in the discrimination mode, establishes the audio level for pinpointing, and establishes a reference point for tuning the machine to ground balance it .

TONE ID - Is the ability of the detector to generate different audio tones for each target’s conductivity range such as, low tone for junk and nickels and high tone for all other coins.

VISUAL ID - Sometimes called VID or TID that gives a visual identification of a target and its depth, or size in the case of imaging detectors.

WIDE RESPONSE - This is caused by a target that generates an audio signal over an area wider than the searchcoil, as opposed to TIGHT RESPONSE which produces a signal much smaller than the diameter of the coil.

ZERO DISCRIMINATION - This is a control that allows the acceptance of all metals at zero setting.

---BR  srevis@ix.netcom.com