metal detectors reviews beginners
In recent years, archaeologists and treasure hunters are increasingly resorting to various achievements of science to discover the land of invisible objects .
The principle of operation of metal detectors Metal – an electronic device that detects the presence of metal without contact with him , and informs the operator of this fact deflection etc.
When the device is in the search head creates an electromagnetic field which extends into the environment. On metal surfaces , caught in the zone of action of the search coil by electromagnetic fields arise so-called eddy currents . These eddy currents create their own counter electromagnetic fields, leading to a decrease in power of the electromagnetic field generated by the search coil , which is fixed and the electronic circuitry of the device. Furthermore, this secondary field distorts the configuration of the main field , which is also detected by the instrument. Electronic circuit detector processes the information and signals detection of metal. Metals such as gold , silver , copper has a high electrical conductivity compared with the iron thin foil of aluminum , nickel, and minerals. Determination of the metal in the object based on the measured conductivity of the object.
In the most general form of metal detectors can be divided into the following groups : Instruments for Beginners – cheap instruments oriented to research on the beaches and well suited to the acquisition of the initial experience with metal , such devices have 1-2 controls and are often one mode – dynamic discrimination.
Computerized devices intended for advanced users , allow for a detailed analysis of hidden objects by size , metal and depth , and their adjustment is usually carried out using a small keypad and LCD display ;
Department – aimed at solving a wide range of tasks , from entertainment on the beach to a serious search for ” treasures .” To work with such devices requires some preparation ; devices have several modes of operation , among which are bound to have a static mode of accurate detection . To search for small objects ( coins , jewelry, nuggets ) to a depth of 40 cm in the soil and large ( the size of a teapot and more) to a depth of 1-1.5 m Typically, this devices operating on the principle of ” transmitter-receiver ” induction balance. Transmitting and receiving coils are located in the same plane and form a search head. Head diameter of 10-40 cm ( most running 21 – cm).
Deep – to search only for large objects at a depth of 2-6 m devices utilize the principle of RF, and the coils are located at a great distance from each other ( 50-100 cm) in perpendicular planes. For these purposes the devices and pulse diameter coil meter or more . These devices look good chests , safes, lost appliances, etc. , but they are not sensitive to the coins and other small items and do not distinguish between metals . Underwater – sealed devices with a specific indication for searching underwater diving. In the majority of these devices use pulse induction principle , which significantly reduces the effect of water as an electrically conductive medium on the search . The depth of the pulse detection device ( not only underwater ) are usually longer than TR / VLF. These devices do not require manual tuning , but have difficulty in distinguishing between metals. Artisanal – for pre-emptive search individual objects made of precious metals ( gold nuggets , silver). Usually it TR / VLF apparatus for searching gold optimized for searching small nuggets that requires a different operating frequency, than the universal device .
Industrial – search for pipes, cables and other underground utilities. This may also include magnetometers to find iron. Their principle of operation is somewhat different from the induction metal detectors.
Underlying instruments for the search of large objects ( considered large object with a surface area of over 400 sq. m . Qv) manufactured by all major U.S. firms . Increasing the depth of the search is performed in all devices , the diversity of transmitting and receiving coils in space. Coils are made in two exploratory head rigidly connected to each other pole. Thus one reel in the working position of the device is parallel to the ground surface , the other – perpendicularly. Dimensions of the coils about 25×40 cm One of the coils emits electromagnetic waves with a frequency of 12-82 kHz , and the other receives the reflected signal.
Search method such devices is different from a single head universal search with metal detectors and has several features :
1. Scan not performed ground vibrational motions of the search head as close to the ground , and wiring of the device parallel to the ground , covering the band equal to the width of the coil ( about 25 cm ) . And so the band for the band. When this coil is not necessary to move towards the ground.
2 . These devices can not be checked and adjusted in the room , especially at home, because of the reflection of electromagnetic waves from the walls and utensils.
3 . Devices work well on the ground , but if you dug a trench in search of treasure , the reflection from the walls create false signals. In this case, you should move to a single head unit.
4 . Unlike universal single-head devices , deep devices do not respond to small objects at a shallow depth , therefore small metal garbage does not interfere with the search. 5 . Underlying instruments do not distinguish metals .
The most popular underlying instruments :
garrett depth multiplier
fisher gemini 3
pulse star ii
whites tm 808
ground probing radar- gpr
Other than those listed in this group also includes appliances: TM 800 – firm White’s; TM 900 – company Discovery; 2B Mega Explorer and models little-known firms .
Now, almost any of the above types of devices you can buy or order . Buy the best instrument in specialized firms that provide you with detailed information to help in the selection of the model and give a guarantee on the work of the unit.
Every year the area of use of metal detectors in various spheres of human activity. For the military, it is primarily a minesweeper . It does not require the ability of the instrument to distinguish metals . Until recently, was not required and high sensitivity , however, with the advent of plastic mines situation has changed in a plastic or ceramic mine remained one irreplaceable metal piece – a small spring in the detonator . It can only detect highly sensitive instrument .
In forensics and security structures metal used now wider than elsewhere. Anyone faced similar devices when entering the bank, airport or nightclub. First of all , this ” magnetic gate” when passing through that can detect even small metal objects. Often when a person after surgery remains a metal object (such as titanium rods in fractures ) , and very difficult to prove the guard that is not disguised as clothing knife or a gun . Then comes to help small detector for personal inspection. They are easily and accurately localized suspicious object . Necessarily similar devices equipped with internal forces guarding the prison . Terrorists often the practice of sending letters to their inherent explosive devices , mainly in the media. Trying to protect yourself from this , large institutions have special devices for checking incoming e-mail correspondence .
No self-respecting company for the production of food , whether confectionery or sausage shop , not without a metal detector . In countries with developed structures entering the consumer market , for example, a nail into a sausage – a sure path to bankruptcy and justice personnel. Metal detectors are essential in the construction and repair work in the process . Difficult to do without this device, if you want to plan the renovation of an old building, for which no drawings arrangement of beams and other supporting structures (not peck same architectural monument, anywhere ), or if you want to trace in underground pipe or electric cable , or drill a hole in wall of the house without damaging communications. During the processing of wood to save the saw or other equipment to avoid damage , you can only see a metal timber . Special frame mounted to the circular saw , automatically stop the conveyor when metal is detected in the wood. When sorting garbage at waste treatment plants is necessary to sort the trash from metal objects. Well, if the iron objects , and you can remove the magnet . Detect and remove non-magnetic metal objects can only induction metal detector.
In mining , especially of native gold , the metal is irreplaceable. Many mines in America, Australia and other countries have experienced a rebirth when using metal detectors prospectors productivity increased tenfold.
Archaeologist Metal help determine the most promising place for detailed excavations will enable to extract interesting findings where continuous excavations simply impossible for various reasons.
Side by side with archaeologists work seekers and treasure hoards . With anything you can not compare the joy of discovery , whether it is first found an ancient coin , lost centuries ago ring or jewelry of ancient treasure . Treasure Hunt captures everyone who picked up a metal detector. Namely the development of hardware devices for hunters reached the greatest perfection in the sensitivity and discrimination ( sifting unwanted finds) . Find lost objects people , a kind of “home archeology” in America has reached a grand scale. There are clubs searchers collectors finds , for example, buckles on belts or cufflinks . Issued special magazines , there are dozens of companies producing equipment for hunters .
The difference between cheap and expensive models lies only in the techniques and methods of radio wave radiation capture and processing and interpretation of secondary signals . More expensive instrument can determine with some degree of probability the detected metal type before removing it , determine its depth , can eliminate the influence of the electrical conductivity of the soil minerals , and have many different additional features that enhance the performance and efficiency of the search , which are absent in the cheap devices. Buying a device for the first time , try to avoid as too cheap models and expensive professional equipment. Cheap, poorly sensitive device may not meet the expectations and unnecessarily disappoint novice in finding a detector . It is likely that , for the first time faced with expensive computerized device , it will be difficult to learn to use it quickly and efficiently.
Instruments to search for gold nuggets
fisher gold bug ii
garrett scorpion gold stinger
tesoro diablo umax
tesoro lobo supertraq
whites goldmaster 3
whites goldmaster 4 / B
Worthy of its own decision is the task of finding gold nuggets . The fact that the universal detection of gold TR / VLF devices , fine particles of metal can be taken per unit pellet ferrous metals are not detected . In addition, the outputs of gold are often accompanied by ” black sand ” , containing magnetite, as well as strong ground mineralization . To overcome these effects increases with the operating frequency of 2 – 7 kHz (for versatile devices ) to 18 – 70 kHz ( from specialist to find gold) and search using elliptic heads.
Became widely known modified pulsed devices, allowing to look very effective small gold items or parts thereof on the beaches and shallow waters in the surf zone .
Other than those listed in this group are also devices : SD 2100 , SD2200, Eldorado MKII company Minelab and some other models little-known firms .
With the advent in the early 70 -ies of XX century, high-speed digital and quantum proton magnetometers measuring the magnitude of geomagnetic induction , search and study of archaeological objects with residual magnetization or induction , including submarines , became possible at greater depths of their occurrence on a very large areas with a high probability of detection . Quantitative interpretation of anomalies of objects to determine not only their location , but also give information on the magnetic moment , mass, geometry and depth .
Application of the tablets difficult to wooded land area, out in the bush , in the marshes , the vast water areas . Route and the distance between the measurements are chosen so that the whole plot turned overlapped network measuring not less than 1×1 or 2×2 m Ultimately , identifies the points corresponding to magnetic anomalies . The advantage of the free search – extraordinary simplicity and reliability of the detection . Furthermore, the independence of geometrically regular set allows you to work on the network populated territory in the bushes , in the swamp, open water . Application of the method is difficult in areas with high geomagnetic field gradients , in particular in the range of modern buildings , indoors , and near the outlets of crystalline rocks.
Special task – find wrecks . To localize the magnetized objects at the bottom of reservoirs at depths of 20-30 meters, used a specially designed bottom magnetometer , which magnetically element is placed in a non-magnetic , sealed box , can be lowered into the water . Working with a magnetometer operating from nonmagnetic small boat by free search . Possible and micro magnetic survey on pre scribed network.