best reviews metal detectors for gold
Interesting information about treasure hunters
Set up a metal detector
The maximum efficiency of metal detectors based on the principle of induction balance depends significantly on their fine-tuning. An incorrectly configured device will not detect deep or small objects (deep objects are understood to be the size of a coin at a depth of 30 cm). Moreover, the more powerful the device, the more important it is to set up. Less powerful devices respond to incorrect setting to a lesser extent. Detailed instructions for setting up specific appliances are provided in the accompanying manuals. Only general comments on this subject concerning any metal detectors are given here.

Typically, the setting includes the following steps:

Adjustment of the threshold
The adjustment from the ground;
Sensitivity adjustment
setting the level of discrimination.
Set the threshold

Adjusting the threshold, or minimum sound background still audible by the operator, is the first and important stage of setting up the device. For some modern dynamic metal detectors, the threshold is set only in static “All Metals” search mode, whereas in “Discrimination” mode the device works without a threshold background (silent search). Nevertheless, it is important to set the necessary threshold in all metals mode for the most effective operation in this mode. To properly adjust the threshold, the coil is kept at a distance of 70-90 cm from the ground and metal objects and with the help of the handle setting the threshold set a barely audible permanent sound background, which, in fact, is called the threshold. This background should be minimal and maintained at this level for the duration of the device.
Deep or small objects do not give a clear signal, but by changing the threshold that our ear easily distinguishes, you will already know that under the coil is some metal object. This is exactly what the need for the right setting of the threshold is. If it gets louder or disappears, for example, due to temperature fluctuations or a bad pound, some devices (Imperial 300, TM 808) with a special button can instantly return it to its original value. Sometimes you have to resort to this button all the time. Therefore, a special scheme was developed for the convenience of work, allowing automatic adjustment of the threshold. This feature is called auto-building. Some devices must first adjust the threshold manually, and then use the Auto-Adjustment switch to support the threshold automatically at a predetermined level while working with the device.

Auto-adjustment is an important component of modern dynamic metal detectors. Low-cost metal detector models usually have a constant average threshold level, which is not always convenient when working in All Metals mode due to a constant sound background.

Properly setting the threshold is important for manual lyepree from the ground.

Cleaning from the ground

The dearrangement from the pound is necessary to achieve maximum depth of action of the device, especially in conditions of strong mineralization of the pound. For most modern metal detectors, this operation is performed automatically and continuously as mineralization changes. Thus, the information below is related to the devices that have a hand-built handle from the ground.

The ultimate goal of the adjustment from the ground is the same threshold background when the coil is raised and lowered. The first and most important stage of excavation from the ground is the choice of a site of soil free of metal and minerals such as magnetite. The choice of such a site should be conducted in the “All metals” mode at the middle position of the handle of the construction. Two types of such handles are used - one-turn with a scale of 1 to 10 and ten-turn. To begin with, you need to install the handle in the first case in position 5, in the second - to make 5 turns in the opposite direction of the twig of difficult rotation. (Generally, this pen can rotate in any direction indefinitely, passing 10 revolutions through the friction zone, which can be considered as the starting point).

There are two methods of building from the ground. The first, so-called static method, when after each adjustment of the handle of the adjustment from the pound, the level of the threshold background is adjusted manually by the other, dynamic method, provides for the automatic setting of the threshold during the adjustment process. Let’s take a look at how the pound is rebuilt in both cases.

If you use the static method, lift the coil above the pound to a height of 35-40 cm. Press and release the button (or spring switch) of the threshold adjustment, then lower the coil to a distance of about 2 cm from the pound and pay attention to the threshold background, which may increase or decrease. If the background volume has increased, turn the handle of the extension from the pound to one division or one turn in the direction of lowering the volume. Lift the coil again and press and release the threshold adjustment button. If the volume of the threshold background is reduced when the coil is lowered, turn the handle of the extension from the pound in the opposite direction to half of the division or half of the turn in the opposite direction. Then lift the coil and set the threshold. Repeating this procedure several times, make sure that the volume of the threshold background would be the same when the coil is lowered and raised.

How to check the original device of the company Minelab or fake
To use the dynamic method, the metal detector must have an automatic threshold setting. The process of de-construction from the ground in this case is that with one hand you lift and lower the coil, while the other hand rotate the handle of the extension from the ground until the threshold background is the same at the raised and lowered coil. Compared to static, this method is more convenient, but not all devices have this capability.

These procedures significantly increase the efficiency of the metal detector, although, unfortunately, it should be noted that the ideal 100% rebuilding from the ground is possible only theoretically. The presence of electrically conductive minerals in the pound leads to the appearance of secondary signals, masking the main signal from the object, thereby reducing the depth of the device. However, by adjusting sensitivity, the efficiency of the metal detector can be improved.

Sensitivity adjustment

Modern metal detectors have a fairly high sensitivity. So, the coin (in the air) they feel at a distance of 30-40 cm. However, to detect the same coin in the pound at such depth the device can only if the coin lay in it long enough, oxidized and oxidized around it in the form of a halo, as if increasing the area of the coin.

It is known that the depth of the detection of the object in the pound is directly proportional to the area of this object facing the coil. When the area is large, the secondary signal created by the object is quite strong. The smaller the object and the deeper it is, the weaker the signal. For example, the device will react to a samovar buried at a depth of 1 m, but no metal detector will be able to detect a coin at this depth. The fact is that even with the correct adjustment from the ground there are additional secondary signals from the minerals surrounding the coin, which the device should separate from the main signal coming from the object. If we set the sensitivity handle to the maximum value, it will also increase the harmful signals from soil minerals. Therefore, on highly mineralized soils the device will work better at a lower level of sensitivity, because weak signals from the object will be heard more clearly. Thus, start with the maximum level of sensitivity, but then reduce it to reasonable limits, if the soil is strongly mineralized.

Setting the level of discrimination

Discrimination refers to a metal detector mode in which the device does not respond to unwanted objects. By changing the level of discrimination, you can ignore any undesirable objects or groups of such objects.

On rice. 22 presented a number of items in order of increasing their electrical conductivity. Small objects related to the garbage discharge have lower electrical conductivity, and it is relatively easy to delineate from them, increasing the level of discrimination. Objects with high electrical conductivity (or large size) do not allow them to be rebuilt and will be perceived by the device even at the maximum level of discrimination. It should be borne in mind that, adjusting from the tongues of cans, we will lose thin gold rings and other small valuable objects, and very thin gold chains can not be detected by most metal detectors even at a shallow depth.

Fig. 22. A number of items in order of increasing their electrical conductivity

The level of discrimination has a great impact on the depth of detection of objects when working on mineralized soils (Figure 23).

The impact of soil mineralization and discrimination on the depth of object detection

Curve 1 (good soil) shows that even at the level of discrimination 10, a silver coin can be detected at a depth of up to 28 cm, with most of the garbage the device ignores.

Curve 2 refers to the moderately mineralized pound. The same coin in such a pound can be found only at a depth of up to 15 cm.

Curve 3 characterizes a strongly mineralized pound. In this case, the loss of depth is maximum. When you set the level of discrimination above 5 large silver coin can be found only at a depth of 5 cm.

Recently, there have been devices with the possibility of selective discrimination, when individual undesirable objects or groups of objects are ignored, both with low electrical conductivity (nails, foil, etc.) and high (tongues from cans). Some metal detectors allow you to adjust the width of the ignoring windows quite wide.

It follows from the above that a minimum of discrimination should be used when working on highly mineralized soils. At the same time, of course, will have to dig up more finds related to the discharge of garbage. At the initial stage of the development of the device it is recommended not to use discrimination at all and to dig up everything in a row.