Suitable for
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Ground. Metal detectors designed to find metal objects buried in the ground - from coins and other historical artifacts to pipelines and caches. They can have different characteristics and scope of application - from the simplest models, suitable only for collecting scrap metal, to powerful professional devices capable of searching even at a depth of a couple of meters. The coil can be protected from moisture (see below), but ground metal detectors are not designed for complete immersion in water.
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Underwater. Metal detectors, designed, as the name suggests, to search for objects under water - primarily at the bottom of reservoirs. Their main features are due to optimization for the environment: a sealed waterproof case (in most cases, with the ability to submerge the entire body to a depth of several meters), the ability to work with wet salty soils, and a weight distribution designed for ease of use under water. Also, such models are usually equipped with waterproof headphones. Note that buying such a device for land use is hardly justified: holding an underwater metal detector in the air is not as convenient as a regular ground detector, and the expensive moisture protection of the case loses all its meaning.
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Inspector. Devices designed to conduct searches and search for metal objects on the human body, under clothing. They are used by law enfo
...rcement agencies, security services at airports, train stations, security agencies, etc. Note that in this case we are not talking about stationary “frames”, but only about hand-held detectors. Almost all of them belong to pinpointers (see “Type”) and have a fairly compact size. Thanks to this, the device can be used as a portable device for express inspections, constantly carried with you along with other equipment. However, such a detector can also be useful at a stationary checkpoint, in addition to the frame - it helps to determine exactly where on the body the object that “disturbed” the frame is located.
— For mine clearance. Highly specialized metal detectors for detecting mines or other explosive objects left by the echo of wars and hostilities. Such devices do not need to separate finds by type of metal. Their main purpose is to search for large projectiles, but there are other types of devices for solving specific problems (for example, detecting plastid with a fuse). Small pieces of hardware are usually ignored by such metal detectors. Mine clearance detectors are rarely found in common use, and they are incredibly expensive. Devices for this purpose are heavy and inconvenient, but durable and resistant to weather conditions. They are aimed at professional use by the military and rescue workers.Shape
The shape of the coil (frame) of the metal detector.
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Round. The traditional form used in almost all types of ground and underwater metal detectors (see "Type"); the only exceptions are models that work according to the RF method (see "Operating principle"). When using concentric coils (see "Coil Type"), this option allows you to create a conical field, which is convenient for pinpointing the location of the find, but reduces the covered area and makes it difficult to search over a large area; models with DD coils do not have this drawback.
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Elliptical. The shape in the form of a longitudinally elongated ellipse allows you to somewhat "stretch" the field created by the metal detector in length. This is especially true for coils of the concentric type — however, such an expansion somewhat reduces the positioning accuracy of individual finds. But in coils of the DD type, where the accuracy is by definition low, the choice between round and elliptical shape is most often not fundamental.
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Rectangular. A specific form used in RF or PI instruments. For technical reasons, it is considered optimal for such devices, but it is practically not found in other types of metal detectors.
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Butterfly. Another option used in DD coils along with the ellipse (see above). In fact, it consists of two elliptical windings
..., partially combined and resembling butterfly wings in shape — hence the name. This option is typical mainly for large-sized DD coils; with a large width, it is considered more optimal than an ellipse.Dimensions (WxD)
The size of the standard coil (frame) of the metal detector. Theoretically, the larger it is, the deeper the device is able to “see” and the more space it captures in one pass, but the worse it is suitable for searching for small objects and the lower the accuracy with which it localizes them. At the same time, these characteristics depend on so many other factors that in fact, the size of the coil itself affects them very little.
Note that for coils (frames) of an elliptical shape, only one size can be indicated — along the length.
Number of coils
The number of coils provided in the scope of delivery of the metal detector.
Emitter-coils are used in metal detectors with all operating principles (see above), except for RF (frames are more justified for them). Also note that, unlike the frames, such emitters are installed only one at a time, and even a paired DD type emitter (see "Coil type") is considered one coil. So if there are several coils in the kit, this means that they are interchangeable. Such a complete set is convenient in that it allows you to choose a working nozzle depending on the specifics of the situation. For example, for the initial search, you can use a large coil, with low accuracy and wide coverage; and having found something interesting, you can put a "sniper" attachment and determine the exact location of the find. However, the features of such a configuration may be different, interchangeable coils may have a specialization in metals, soil types, etc., and it's ok to clarify their features separately before buying.
Also note that some models may not be equipped with coils at all. On the one hand, this means additional efforts to select and purchase these parts, on the other hand, it allows you to choose them yourself according to your own requirements, without relying on the manufacturer's decisions. This option is useful for advanced "treasure hunters".
Number of detection frequencies
The number of individual operating frequencies at which the metal detector can operate. For more on the frequencies themselves, see "Detection Frequency" below; here we note that the more options (
3 frequencies and more) are provided in the design, the wider the capabilities of the metal detector, the easier it is to adjust it to the specifics of the objects being searched and the environment. However, most models have
one frequency.
Detection frequency
The operating frequency (or frequency range) of the metal detector. This is one of the most important parameters when choosing a device, because the optimal frequency for different cases will be different — depending on the size and material of the items being searched, the characteristics of the soil and other factors. Detailed recommendations on the choice of frequency for each specific situation can be found in special sources; And already on the basis of this information, it is worth choosing a specific model.
Note that the actual frequency at which the metal detector will operate also depends on the installed coil — they are usually made for a specific frequency. Therefore, to use the full capabilities of the device with the ability to adjust this parameter, you may need replaceable coils.
Max. detection depth
The greatest depth at which a metal detector is guaranteed to be able to detect a metal object. Note that this parameter is most often quite approximate, moreover, somewhat conditional. This is due to the fact that it is usually indicated for an perfect environment (low-mineralized soil, a fairly large object, the material of which optimally matches the frequency of detection of the coil, etc.), and even for such conditions it is difficult to derive an absolutely accurate value. Therefore, in fact, the detection depth is highly dependent on a number of additional factors (from soil characteristics to user skills) and can be significantly less than indicated in the characteristics. Nevertheless, the claimed depth describes the capabilities of the metal detector quite well, and it is quite possible to compare different models with each other.
Note that a large depth not only increases the cost of the device, but can also adversely affect its ability to detect small objects.
Coin detection depth
The deepest depth at which a metal detector is capable of detecting small coins and other objects of similar size. Many users buy a device with the intention of “hunting” for metal trifles, so manufacturers often indicate this parameter separately in the specifications. Due to the small size of the coins, their detection depth is usually much less than the total maximum detection depth (see above).
Number of modes
The number of pre-installed programs for searching for various materials. Their number reflects the capabilities of a particular model, allowing you to start working right off the bat.