"How deep does he go back?" - this question is often asked of those who see the metal detector for the first time. A specific answer cannot be given, since many different factors affect the depth of detection of metal. Therefore, none advertising metal detectors you will not find mention of the depth of the device.
Of the factors that determine the depth of detection of the object, only the electromagnetic field and an electronic circuit that interprets the change of the field are functions of the of the device itself. Other factors depend on the object itself and from the surrounding environment.
First of all, the larger the object, the deeper it can be detected (but before certain limits). For example, a silver fifty most modern devices can detect at a depth of 20-30 cm, while cans of beer can be found at a depth of 40-60 cm, However if the ground is heavily minerals, depth of detection can be greatly reduced, especially for objects small size. Affects the humidity of the pound. Usually it increases the depth of detection, but not in all cases. Sometimes dry soil gives the best results.
Plays a role and how long the objects in the ground. Thus, copper and bronze coins had lain in the earth for centuries and covered with a crust of oxides, can be detected at a greater depth compared to modern coins. In case that the oxides of copper conduct electricity and, extending around coins, like to increase its size. When corrosion of silver are often formed sulfides, which reduce the depth of detection of such silver coins.
The shape of the object also affects the depth of detection. Objects with holes, for example the ring you can find at a greater depth than the same coin size. Hard (in the sense of detection) are very thin and gold silver chains. Of great importance is the orientation of the object in the ground. Coin standing on the edge, sometimes you cannot detect and at a depth of 10 cm. luckily for the majority of coins laid flat.
Another important factor is the composition of the metal from which is made the object. Some metals have a high electrical conductivity, but often in the alloys they lose this property, and finding them becomes harder. An example would to serve an alloy of gold and silver. Both metals are good conductors, but the alloy electrum (50% Au And 50% Ag) has a bad conductor of current.
On the depth of detection is also influenced by the level of discrimination used. When small levels the difference is not so noticeable, however with the increase of discrimination there is a significant loss of depth, especially for small objects and the use of static devices. The dynamic impact of metal detectors discrimination on the depth of detection is affected to a lesser extent
The sensitivity level is, of course, also affects depth. As a rule, all want to install the pen sensitivity on high, but with strong mineralization of the soil this leads to the appearance of false signals and unstable the operation of the device. Therefore, at high sensitivity depth detection may actually be markedly lower than in those with less sensitivity. In addition to bad ground is often necessary to reduce the sensitivity and different electrical interference (power lines, powerful generators, radars and etc.). In these cases, often the reduced sensitivity will help to increase the depth the object detection.
Modern metal detectors detect the object by its volume (mass), and surface area facing to the search coil. If you already have the metal detector, you can verify this yourself by moving around the coil large coin to the coil plane, and then edge to the coil. In the second case depth of detection is almost two times less.
Thus, summarizing the foregoing and in other circumstances, the depth of detection of objects is influenced by the following factors:
1. The degree and type of ground mineralization.
2. The soil moisture content.
3. The size of the object.
4. The shape of the object.
5. The composition of the metal object.
6. The orientation of the object.
7. The type and degree of corrosion of the object.
8. The presence of electrical noise.
9. The type of detector.
10. Operating frequency of the detector.
11. The size and type of the search coil
12. The level of discrimination.
13. The sensitivity level.
14. The quality settings of the metal detector.
15. The condition of the batteries.
16. The experience of the operator.
17. The speed of movement of the coil.
Special deep metal detectors can detect large objects at the depth of a few meters, but small objects the size of a coin they are not feel.
The following is the approximate depth at which in normal soil to detect various objects using modern metal detectors.
Car, tank - 4-6 m
The iron barrel of 200 l 2-4 m
The 20L - 1.5-2 m
Soldier's helmet - 0.7 to 1.3 m
Rifle sleeve - 0,2-0,4 m
Copper coin - 0,15-0,3 m
Pipe diameter 50 mm - 1-1,5 m
Author: L. V. Bulgak