What to take with you for search work with a metal detector. Scheme, description

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What to take with you for search work with a metal detector. Encyclopedia of radio electronics and electrical engineering

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Encyclopedia of radio electronics and electrical engineering / metal detectors

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Necessary fixtures and tools

In addition to a metal detector, some more devices and tools are needed. They will help to extract the found object, put it down for further transportation, and document the place of the find.

First, you need a sharpened shovel. It is very important not to forget about sharpening the blade of a shovel before each search with a metal detector, because you will have to dig quite a lot. This will save time, effort and maintain a good mood during the search.
Secondly, you need a probe. The probe is a smooth steel bar with a diameter of about 5 mm with a rounded end. The length of the probe should not exceed 40-50 cm, otherwise it will interfere with transportation. The probe is usually used to determine the location of an object underground.
Thirdly, you need a backpack-case made of water-repellent material for a metal detector to protect the device from rain and mechanical damage during transportation. It is best that the backpack-case also have pockets for additional equipment.
Fourthly, you need a sharp hatchet or pruner, because the roots of trees or dense vegetation often interfere with excavations.
Fifthly, you need a box for finds, because small and fragile finds should not be scattered in pockets and a backpack. Plastic boxes for fishing tackle are very convenient for these purposes.
Sixth, you need a flashlight, spare batteries for both the flashlight and the metal detector, and headphones. It is advisable to use the latter when searching in places where there are other people besides you.
Seventh, we need the means for documentation: a camera, a notebook, a map, a pen, a pencil. It would be useful to write down the time when the finds appeared, the details of the excavations in a notebook, and put the place on the map. We also need flags of white, red colors, pegs, rope, etc.
Eighth, you need a first aid kit: emergency supplies such as band-aid, hydrogen peroxide, iodine, aspirin, pain reliever and activated charcoal, mosquito repellent.
Ninth, an oilcloth 1,5 x 1,5 (or 2 x 2) m will be very useful. It is convenient to grind the earth taken out during excavations on it, to conduct an additional search for valuables in the resulting layer.
And, tenthly, you need to dress properly, have gloves and a hat. Clothing must be durable. Camouflage cloth is best. The most important thing in the clothes of a searcher is, of course, comfortable shoes, because you have to walk a lot. Shoes must be leather and must have thick soles. A good option is hunting shoes or shoes for tourists, which can be purchased in specialized stores. You can take the most ordinary cotton gardening gloves, rubberized on one side, because you have to pick in the ground not only with a shovel, but also with your hands. In some cases (for example, in the case of swampy terrain or rain), rubber boots may be needed.

Search rules

It is useful to remember a few search rules:

Rule 1. There is a strong dependence of the correctness of identification on the speed of the coil and its trajectory. Discrimination worsens at very fast, very slow or uneven speeds.
Rule 2. The best quality of identification is observed when the coil is advanced with a small amplitude exactly over the center of the target.
Rule 3. If there is a difference in ground level above the target, then the identification of the object worsens. It is necessary to reduce the amplitude of the swing of the coil and try to scan from a different angle.
Rule 4. It is very important to keep the coil as close to the ground as possible. Do not sacrifice search depth at the expense of scanning speed.
Rule 5. If, when moving in one direction, the device shows that there is an object made of non-ferrous metal in the ground, and when moving in the opposite direction, it is silent, then move the coil perpendicular to the original direction. Perhaps the stability of the signal and the exact identification of the object will appear.
Rule 6. If during scanning the device shows that there is an object made of metal in the ground, and the exact identification of the object is impossible, then you should not ignore such signals. In this case, you need to determine the exact location of the object, level or remove the top layer of soil above the center of the object and again pass the coil at different angles - the signal level will increase and the identification will become more accurate.

About Search Discrimination

Let us first consider the necessary terms and definitions.

Discrimination - the ability of the device to distinguish between metal objects of different composition. This ability is:

in reaction (for example, by a sound signal) to some objects;
in the absence of reaction to other objects.

Discrimination is usually adjusted by the discrimination level control, which determines which object will be reacted to. The level of discrimination in simple (non-computerized) devices corresponds to the specific conductivity of the objects, starting from which the device gives a reaction.

Small objects can be arranged in the following sequence depending on their conductivity: nails -> foil -> nickel coins -> can pull tabs -> gold jewelry -> corks -> copper coins -> silver.

Therefore, the corresponding regulators are calibrated in such terms.

In computerized devices, the entire range of objects is divided into segments (up to 190 segments), for each of which you can set an action: react; ignore.

The adjustment in this case is carried out in the learning mode - by bringing valuable and harmful objects to the coil.

Range Discrimination - the ability to set a selective reaction to certain objects for non-computerized devices, for example, make the device react to nickel coins and ignore reeds and plugs.

It is implemented by introducing a second discrimination controller that sets the position of an additional discrimination range for objects.

Consider the issue of discrimination using the Tracker IV metal detector as an example, which has a discrimination level adjustment knob and a toggle switch (full/all metals/tone).

The operating modes of the discriminator in the Bounty Hunter Tracker IV metal detector are switched using a 3-position toggle switch:

"Tone Discrimination" (tonal discrimination) / "All Metals" (all metals) / "Full Discrimination" (full discrimination).

Mode 1. "All Metals" - Discrimination control does not affect anything. All metals emit the same tone.

Mode 2. "Full Discrimination" - the more you turn (clockwise) the knob, the higher the discrimination range will be and the more metal debris will be filtered out.

If you adjust the discrimination so as to get rid of the signals from vodka caps, aluminum foil, etc., then both gold rings and nickel-containing alloys will practically cease to be detected.

Mode 3. "Tone Discrimination" - selection in tone mode is used, the metal detector will divide targets into 4 classes.

Class 1. Iron and steel objects do not emit any tone.
Grade 2. A low tone indicates that gold or nickel has been found.
Grade 3. A high tone indicates that copper, silver, or brass/bronze (modern coins) has been found.
Class 4. A broken tone would indicate that the object found is most likely an aluminum cap, foil, or a piece of aluminum wire.

You should use the "Tone Discrimination" mode only if there is a large amount of metal debris in the ground. In places that are cleaner from debris, it is justified to use the "All Metals" mode. Without discrimination, the detection depth of the metal detector is greater.

About detection depth

Search Depth - This is the most important parameter of the metal detector.

Oddly enough, but none of the prospectuses of foreign manufacturing companies indicate such an important characteristic of a metal detector as the depth of its action. This is because it depends on many factors:

soil type;
search environments;
object material;
coil size;
state of the power supply;
operator experience;
the degree of discrimination;
using headphones, etc.

The better (more expensive) the metal detector, the greater the distance it detects larger objects. But still, everything has limits, and even the best instruments cannot feel a 20-liter canister more than 2 m in air.

When an object is in the ground, the conditions for finding it in most soils worsen. On some soils, a coin (the same 5 kopecks) sometimes cannot be found, even if it simply lies on the surface.

Many devices (more expensive) allow you to largely decouple from the influence of the ground, but the detection depth will be less than in air. Some soil minerals that are common in the places where gold nuggets are located strongly interfere with the search - magnetite, chalcopyrite, etc., which give false signals (as from metal), thus greatly reducing the search efficiency.

Pulse metal detectors are less affected by soil minerals. Their depth of action in the ground and salt water is greater compared to the most common VLF metal detectors and is comparable to the detection distance of the same object in the air.

Finally, there are devices with spaced coils (TM 800, TM 808, Gemini-3, CX with a depth multiplier, etc.), the depth of which on large objects reaches from 1 to 4 m depending on the type of soil. Their advantage is that that they do not react to small objects the size of a coin: corks, nails, pieces of foil that make up metal debris.

Training search for beginners

Before actually going out into the field in search of coins, rarities and other valuable finds, we recommend that beginners first find many well-known items made of ferrous metal (nails, bolts, tools, etc.) and non-ferrous metal (a piece of foil, a bottle cap, jewelry, etc.). some coins). Scan them with a metal detector in the air to learn how to recognize and remember typical signals. If this is your first time holding a metal detector in your hands, then such preliminary tests are very important.

In the same way, you can study the settings and various modes of operation of the metal detector. The most important of them are "Discrimination", "Sensitivity" and how they affect the performance of the device.

Also, try setting up your own test site. Bury several well-known objects, at a depth of 5 to 20 cm, with a distance of at least 40 cm from each other. Accurately mark the places where and what objects are buried. These tests can be repeated on different types of soil, such as clay soil, loose black soil, sand. Experiment with a metal detector on the ground, constantly listening and studying the signals it gives out.

During practical work on the test site, you will quickly learn to determine the exact location and depth of objects, as well as understand how soil properties affect the depth of detection of objects.

In order to better hear the change in the sound signal, use headphones and be attentive and focused on the work being done.

Author: Dubrovsky S.L.

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