Beat Frequency Induction Many manufacturers of these new devices brought their own ideas to the market. White's Electronics of Oregon began in the 1950s by building a machine called the Oremaster Geiger Counter. Another leader in detector technology was Charles Garrett, who pioneered the BFO (Beat Frequency Oscillator) machine. With the invention and development of the transistor in the 1950s and 1960s, metal detector manufacturers and designers made smaller, lighter machines with improved circuitry, running on small battery packs. Companies sprang up all over the United States and Britain to supply the growing demand. Beat Frequency Induction requires movement of the detector coil; akin to how swinging a conductor near a magnet induces an electric current; except the pulse is electric EMF and not magnetic EMF. Civil engineering In civil engineering, special metal detectors (cover meters) are used to locate reinforcement bars inside walls. American metal finders are a term that refer to the devices and equipment or instruments made by American companies or manufacturers , that can be used to find or detect metal objects nearby or buried underground such as silver or golden coins or small jewelry like rings, collars and so on. Metal finders' more accurate term is: Metal Detectors, as the metal detector's main function is to detect the presence of metal objects including for example underground buried metal targets such as gold treasures, bronze statues, archaeological artifacts made of different metal types. The most common type of metal detector is a hand-held metal detector or coil-based detectors that use a oval-shaped plastic disks with built-in coils made of copper usually, the search coil works as sensor probe and must be swept or moved over the ground to detect the potential metal targets buried underground, when the search coil detect a metal object the device give a feedback as an acoustic feedback as changed audio tone via speaker or earphone, and in most metal detectors the feedback is an analog or digital indicator as a unique number called Target ID based on target metal type.%DIFDELCMD < %DIFDELCMD < %%% These metal detectors first invented and manufactured commercially in United States of America in twentieth century by Fisher Labs in 1930s then other companies like Garrett established and developed the metal detectors in terms of technology and features in following decades to reach the current form of metal detector that is common in use by hobbyists and treasure hunters or gold prospectors. Skilled prospectors have put their confidence in American metal detectors due to the high quality of their industry and low cost of production, they are known all over the world.%DIFDELCMD < %DIFDELCMD < %%% American metal finders The history and development of metal detectors in the United States roots back to the end of the 19th century after a huge development and acquired knowledge during this century in the field of electrical engineering by a lot of scientists and inventors. Many inventors and engineers tried to invent or manufacture a working device to detect or pinpoint the presence of metal objects depending on electrical and related magnetic theories and researches.%DIFDELCMD < %DIFDELCMD < %%% First idea Many scientists, academics, and gold miners started experimenting with the idea or concept of creating a device that could locate metal hidden underground after the widespread adoption of electrically-powered appliances in the mid 1800s. A device like this would be very useful to the many prospectors still searching for gold after the "Gold Rush," period , making the first person to perfect a metal detector extremely wealthy. Gustave Trouvé, a French electrical engineer, invented the first metal detector in 1874. He created a hand-held device in order to locate and separate bullets and other metal objects from human patients.%DIFDELCMD < %DIFDELCMD < %%% Following the assassination of American president James Garfield in 1881, Alexander Graham Bell - the inventor of telephone - attempted to create a metal detector similar to Gustave Trouvé's device. Graham Bell used his unit to try to locate the fatal bullet inside President Garfield's body. Bell's metal detector worked, but the metal coil springs of James Garfield's bed threw the detector off, and the search for the bullet failed. Despite the fact that the first metal detector failed to save the 20th President of the United States, Alexander Graham Bell's system was a viable metal detector, and it served as the blueprint for all subsequent metal detectors.%DIFDELCMD < %DIFDELCMD < %%% These machines were initially very large, complex, and operated on vacuum tubes , however, they were useful, and as a result, their popularity grew. Most notably, after world war these early metal detectors were used to locate and clear landmines and unexploded bombs throughout Europe. Technology development%DIFDELCMD < %DIFDELCMD < %%% Gerhard Fischer Gerhard Fischer developed a portable metal detector in 1925. Fischer's model was first marketed commercially in 1931, and he was responsible for the first large-scale hand-held metal detector development.%DIFDELCMD < %DIFDELCMD < %%% Gerhard Fisher studied electronics at the University of Dresden before immigrating to the United States. When working as a Research Engineer in Los Angeles, California, he came up with the concept of a portable metal detector while working with aircraft radio detection finders. Fisher shared the concept with Albert Einstein, who foresaw the widespread use of hand-held metal detectors. Dr. Gerhard Fisher, the founder of Fisher Research Laboratory, was contracted by the Federal Telegraph Company and Western Air Express to establish airborne direction finding equipment in the late 1920s. He received some of the first patents in the area of radio-based airborne direction finding. He came across some unusual errors in the course of his work, and once he figured out what was wrong, he had the foresight to apply the solution to a totally unrelated area, metal and mineral detection."%DIFDELCMD < %DIFDELCMD < %%% Fisher received the patent for the first portable metal detector in 1925, and in 1931, he marketed his first Fisher device to the general public, and he established a famous Fisher Labs company that started to manufacture and develop hand-held metal detectors and sell it commercially. Charles Garrett%DIFDELCMD < %DIFDELCMD < %%% Despite the fact that Fisher was the first to receive a patent for a metal detector, he was only one of many who improved and mastered the device that is now found in your detector’s shops. Charles Garrett, the founder of Garrett Metal Detectors, was another key figure in the creation of today's metal detectors. Garrett, an electrical engineer by profession, began metal detecting as a pastime in the early 1960s. He tried a number of machines on the market but couldn't find one that could do what he needed. As a result, he started developing his own metal detector. He was able to develop a system that removed oscillator drift, as well as many special search coils that he patented, both of which effectively revolutionized metal detector design at the time.%DIFDELCMD < %DIFDELCMD < %%% To present day In the 1960s, the first industrial metal detectors were produced, and they were widely used for mineral prospecting and other industrial purposes. De-mining (the detection of landmines), the detection of weapons such as knives and guns (particularly in airport security), geophysical prospecting, archaeology, and treasure hunting are just some of the applications.%DIFDELCMD < %DIFDELCMD < %%% Metal detectors are also used to detect foreign bodies in food, as well as steel reinforcement bars in concrete and pipes, as well as wires buried in walls or floors in the building industry. The future of metal detectors is anyone's guess, given the large number of professional and amateur players involved, as well as the rapid speed of technical progress in general. Metal detectors, on the other hand, will almost certainly continue to grow and adapt in order to uncover even more treasure.%DIFDELCMD < %DIFDELCMD < %%% Treasure hunters never give up, and as the history of the metal detector shows, it's these dedicated, creative individuals who have shaped metal detectors into the devices they are today, and who will continue to shape the future of metal detecting Discriminators and circuits Transistors, discriminators, modern search coil designs, and wireless technology, all of which were developed in 1947 by John Bardeen, Walter Brattain, and William Shockley, have had a significant impact on the advancement of metal detectors as we know them today. Both of these factors, as well as others, have contributed to the metal detector's current status as a lightweight, compact, easy-to-use, deep-seeking system.%DIFDELCMD < %DIFDELCMD < %%% The invention of a tunable induction device was the most significant technological advancement in detectors. Two electro-magnetically tuned coils were used in this method. One coil serves as an RF transmitter, while the other serves as a receiver; in some situations, these coils may be tuned to frequencies ranging from 3 to 100 kHz. Due to eddy currents induced in the metal, a signal is detected when metal is present. The fact that every metal has a different phase response when exposed to alternating current allowed detectors to differentiate between metals. Longer waves (low frequency) penetrate the ground deeper and select for high conductivity targets like silver and copper, while shorter waves (higher frequency) select for low conductivity targets like iron. Unfortunately, ground mineralization interference affects high frequency as well. This selectivity or discrimination allowed the development of detectors that could only detect desirable metals.%DIFDELCMD < %DIFDELCMD < %%% Unfortunately, ground mineralization interference affects high frequency as well. This selectivity, or discrimination, allowed the development of detectors that could detect desirable metals while ignoring undesirable metals. Even with discriminators, avoiding undesirable metals was difficult because some of them have similar phase responses (for example, tinfoil and gold), particularly in alloy form. As a result, tuning out those metals incorrectly increased the chance of missing a valuable discovery. Discriminators also had the downside of lowering the sensitivity of the devices.%DIFDELCMD < %DIFDELCMD < %%% Manufacturers and companies Since the beginning of the invention of the metal detector and its commercial sale, many manufacturers of metal detectors were established during the twentieth century in the United States of America. These companies provided dozens of new products and various multi-purpose metal detectors suitable for all prospectors categories from beginners to professionals, and these companies contributed to the development of device technology and its features. By providing improvements and additions to the general design of metal detectors.%DIFDELCMD < %DIFDELCMD < %%% Fisher Labs%DIFDELCMD < %DIFDELCMD < %%% History Dr. Gerhard R. Fisher, the world-famous engineer and inventor who was the first to obtain a patent for the metal detector, founded Fisher Research Labs in 1931. Fisher Research Labs is a made-in-America success story that began in Fisher's garage and has grown from there.%DIFDELCMD < %DIFDELCMD < %%% Fisher Labs, the world's oldest metal detector company, uses cutting-edge technologies to create some of the industry's most reliable devices.%DIFDELCMD < %DIFDELCMD < %%% Dr. Fisher was a Research Engineer in Los Angeles in the late 1920s when he received the first patent for aircraft radio direction finders. He was a German refugee who studied electronics at the University of Dresden. Dr. Albert Einstein was impressed with his groundbreaking work in aviation. Dr. Einstein expected the widespread use of radio direction finders in the air, on land, and at sea after seeing a demonstration of Fisher's equipment.%DIFDELCMD < %DIFDELCMD < %%% Fisher Research Labs was built in Fisher's garage in Palo Alto, California, in 1931. He and four coworkers created the "Metallascope," a tough, user-friendly metal detector. It was an ungainly unit, with two wide, flat wooden boxes containing basic copper coils, five vacuum tubes, and a few assorted parts, by today's standards of lightweight handheld detectors. The Metallascope quickly captured the nation's and, within a brief period, the world's imagination.%DIFDELCMD < %DIFDELCMD < %%% To meet the increasing demand for the Metallascope, also known as the M-Scope, Fisher Labs relocated to a small building at 745 Emerson St. in Palo Alto in 1936. Dr. Fisher received a patent for his invention not long ago. For all forms of electronic metal detection, the M-Scope became the agreed standard.%DIFDELCMD < %DIFDELCMD < %%% It was used by geologists to find ore, fortune seekers to find treasure, service companies to identify underground tubing, timber mills to detect metal inclusions in sawn logs, and law enforcement to discover lost and concealed weapons.%DIFDELCMD < %DIFDELCMD < %%% Fisher relocated to a larger apartment in Palo Alto in 1939, shortly before World War II, at 1961 University Ave. Fisher Research Labs was called upon to devote its scientific expertise to the war effort during World War II and the Korean Conflict, but the M-Scope industry was never ignored.%DIFDELCMD < %DIFDELCMD < %%% Fisher Labs relocated to a new manufacturing plant in Belmont, California, in 1961. Dr. Fisher's reputation and career had left an indelible imprint on the world of electronics by the time he retired in 1967. Fisher Research Labs expanded and relocated to Los Banos, Calif., in 1974, where it remained until 2006, when it was purchased by First Texas Holdings Corporation.%DIFDELCMD < %DIFDELCMD < %%% First Texas relocated the firm to El Paso, Texas, where it continues the Fisher tradition of scientific breakthroughs redefining the state of the art of metal detection. Fisher's vast range of brands, which have the finest ergonomics, most streamlined user interfaces, and innovative ground balance and objective separation capabilities, are the result.%DIFDELCMD < %DIFDELCMD < %%% Technologies developed Fisher was the pioneer in metal detection technology and it is the first to introduce new innovations and technologies in metal detection , treasure detection and security products.%DIFDELCMD < %DIFDELCMD < %%% The company invented or enhanced existed technologies in electromagnetic engineering to get a best devices in term of performance and If you're looking for hidden utilities, security walk through metal detectors, or long-buried treasures, Fisher technology can get the job done quickly. Fisher efficiency and creativity are your trustworthy source for underground finding devices, from analog to digital, in single or multiple frequencies.%DIFDELCMD < %DIFDELCMD < %%% Search Systems%DIFDELCMD < %DIFDELCMD < %%% Search systems in Fisher’s metal detectors include multiple search technologies that rely on electromagnetic technology including VLF , Pulse Induction and other derived technologies for detection of metal using a special features for metal discrimination through signal based Target ID or acoustic output based on metal type .%DIFDELCMD < %DIFDELCMD < %%% Some devices incorporate a mechanism to select predefined settings known as search modes or detection modes that offer a different system for multiple purposes and conditions based on ground terrain , soil type and other factors.%DIFDELCMD < %DIFDELCMD < %%% Search coils developed%DIFDELCMD < %DIFDELCMD < %%% F75%DIFDELCMD < & %%% F70%DIFDELCMD < %DIFDELCMD < %%% 5" DD Round White Coil - Item 5COIL-F75 6-1/2" White Elliptical Concentric Closed Coil - Item 6COIL-E 10" Concentric Elliptical Coil - Item 10COIL-F70 10" DD White Elliptical Closed Coil - Item 10COILDD-F75 11"DD Elliptical Open Coil - Item 11COIL-F75 15" DD Round Open Coil - Item 15COIL-F75%DIFDELCMD < %DIFDELCMD < %%% F5%DIFDELCMD < %DIFDELCMD < %%% 5" DD Round White Coil - Item 5COIL-F5F 8" Concentric Open Coil - Item 8COIL-7TEK 10" Concentric Elliptical Coil - Item 10COIL-F5F 10" DD White Elliptical Closed Coil - Item 10COILDD-FRL 11"DD Elliptical Open Coil - Item 11COIL-F5F%DIFDELCMD < %DIFDELCMD < %%% F4%DIFDELCMD < & %%% F2%DIFDELCMD < %DIFDELCMD < %%% 4” Round Black Concentric Coil-Item 4COILF 8” Concentric Coil-Item 8COIL-7BLKF 10” Concentric Coil-Item 10COILF 11" Elliptical Open Coil - Item 11COIL-F2F 11” DD Bi-Axial Black Coil-Item 11COIL-F4F%DIFDELCMD < %DIFDELCMD < %%% F19%DIFDELCMD < %DIFDELCMD < %%% 5” DD Round White Coil-Item 5COIL-GBUG 10" DD White Elliptical Closed Coil - Item 10COILDD-FRL 11"DD Elliptical Open Coil - Item 11COIL-F5F%DIFDELCMD < %DIFDELCMD < %%% Gold Bug / Pro / DP%DIFDELCMD < %DIFDELCMD < %%% 5” DD Round White Coil-Item 5COIL-GBUG 10” Solid DD White Elliptical Coil-Item 10COILDD-GB 11” DD Bi-Axial Black Coil-Item 11COIL-GB%DIFDELCMD < %DIFDELCMD < %%% Gold Bug 2%DIFDELCMD < %DIFDELCMD < %%% 6-1/2” White Concentric Elliptical Coil-Item 6 COILE-7-GB2 10” White Concentric Elliptical Coil-Item 10 COIL-GB2 14” White Concentric Elliptical Coil-Item 14 COIL-7-GB%DIFDELCMD < %DIFDELCMD < %%% F44%DIFDELCMD < %DIFDELCMD < %%% 4" Round Search Coil - Item 4COIL-FS 7" Round Coil - Item 7COIL-RE-F 9" Concentric Teardrop Coil - Item 9COIL-EE 11" Concentric Teardrop Coil - Item 11COIL-EE 11" DD Elliptical Coil - Item 11COIL-FRL 4" Coil Cover - Item 4COVER 7" Round Coil Cover - Item 7COVER-RE 9" Teardrop Coil Cover - 9COVER-EE 11" Coil Cover - Item COVER-11DD%DIFDELCMD < %DIFDELCMD < %%% Bounty Hunter%DIFDELCMD < %DIFDELCMD < %%% History and Establishing%DIFDELCMD < %DIFDELCMD < %%% Metal detectors from the Bounty Hunter business are plain, fast, and inexpensive devices for the hobby of searching for gold and lost metal items such as rings, coins, and so on.%DIFDELCMD < %DIFDELCMD < %%% The Bounty Hunter corporation is headquartered in El Paso, Texas, and its parent company, First Texas, comprises several metal detector manufacturers, such as Fisher Labs and Teknetics, as well as firms that specialize in other areas, such as night vision systems.%DIFDELCMD < %DIFDELCMD < %%% Technologies They Developed%DIFDELCMD < %DIFDELCMD < %%% The company produces a wide range of metal detector models with various features, including metal detectors for kids, coin shooting detectors for amateurs, and even gold prospectors metal detectors.%DIFDELCMD < %DIFDELCMD < %%% All of the company's metal detectors use electromagnetic equipment, such as very low technology VLF with a search coil system, and they have a search area and a very shallow depth of less than 2 meters underground.%DIFDELCMD < %DIFDELCMD < %%% Throughout its existence, the company has manufactured approximately 55 products, including various devices and related accessories in various models, as well as search coils for various purposes.%DIFDELCMD < %DIFDELCMD < %%% Search Systems%DIFDELCMD < %DIFDELCMD < %%% Multiple search technologies based on electromagnetic technology are available in Bounty Hunter's metal detectors, including VLF, Pulse Induction, and other derived technologies for metal detection using special features.%DIFDELCMD < %DIFDELCMD < %%% Some systems provide a mechanism for selecting predefined settings called search modes or detection modes, which have a different method for different purposes and conditions depending on ground terrain, soil type, and other variables.%DIFDELCMD < %DIFDELCMD < %%% Metal detectors for military uses The first metal detector, designed by Alexander Graham Bell, proved to be a practical metal detector, and it served as the prototype for all subsequent metal detectors.%DIFDELCMD < %DIFDELCMD < %%% Initially, these machines were huge and complex, and they used vacuum tubes to operate.%DIFDELCMD < %DIFDELCMD < %%% Nonetheless, it proved to be useful, and it grew in popularity among users and prospectors for specific applications.%DIFDELCMD < %DIFDELCMD < %%% One of the early common uses of the first metal detectors, for example, was the detection of landmines and unexploded bombs in a number of European countries following the First and Second World Wars.%DIFDELCMD < %DIFDELCMD < %%% Uses and benefits Metal detectors can be used if for several military uses, which can be summarized as follows:%DIFDELCMD < %DIFDELCMD < %%% Exposing the mines planted in the fields during the war or after the end of the war Detect dangerous explosives and cluster bombs dangerous to people's lives Hand-held metal detectors can be used to search people for weapons and explosives%DIFDELCMD < %DIFDELCMD < %%% War Mine Detection Demining, also known as mine removal, is the method of clearing a field of landmines.%DIFDELCMD < %DIFDELCMD < %%% The aim of military operations is to clear a path through a minefield as quickly as possible, which is mostly accomplished using equipment like mine plows and blast waves.%DIFDELCMD < %DIFDELCMD < %%% Humanitarian demining, on the other hand, aims to clear all landmines to a certain depth and make the land secure for human use.%DIFDELCMD < %DIFDELCMD < %%% The process of finding or detection of mines done by a special designed metal detector exclusively developed to detect mines and bombs.%DIFDELCMD < %DIFDELCMD < %%% Landmine detection techniques have been studied in a wide range of ways.%DIFDELCMD < %DIFDELCMD < %%% Electromagnetic technologies are most popular, and one of them (ground penetrating radar) has been used in conjunction with metal detectors.%DIFDELCMD < %DIFDELCMD < %%% Mine casings produce a cavity that can be detected using acoustic methods or sensors to detect vapor leakage from landmines. Rats and mongooses, for example, can walk safely over a minefield and detect explosives, and animals can even be used to screen air samples over possible minefields. Bees, plants, and bacteria may all be useful. Nuclear quadrupole resonance and neutron probes can also be used to detect explosives in landmines.%DIFDELCMD < %DIFDELCMD < %%% Specially trained dogs are often used to focus the search and confirm that an area has been cleared, mines are often cleared using mechanical equipment such as flails and excavators.%DIFDELCMD < %DIFDELCMD < %%% See also List of metal detecting finds DEMIRA Detectorists (BBC Television series) Inductive sensor Induction loop Magnet fishing Portable Antiquities Scheme
Beat Frequency Induction Many manufacturers of these new devices brought their own ideas to the market. White's Electronics of Oregon began in the 1950s by building a machine called the Oremaster Geiger Counter. Another leader in detector technology was Charles Garrett, who pioneered the BFO (Beat Frequency Oscillator) machine. With the invention and development of the transistor in the 1950s and 1960s, metal detector manufacturers and designers made smaller, lighter machines with improved circuitry, running on small battery packs. Companies sprang up all over the United States and Britain to supply the growing demand. Beat Frequency Induction requires movement of the detector coil; akin to how swinging an conductor near a magnet induces an electric current; except the pulse is electric EMF and not magnetic EMF. Civil engineering In civil engineering, special metal detectors (cover meters) are used to locate reinforcement bars inside walls. %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < & %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < & %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% %DIFDELCMD < %DIFDELCMD < %%% See also DEMIRA Detectorists (BBC Television series) Inductive sensor Induction loop Magnet fishing Portable Antiquities Scheme
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American metal finders are a term that refer to the devices and equipment or instruments made by American companies or manufacturers , that can be used to find or detect metal objects nearby or buried underground such as silver or golden coins or small jewelry like rings, collars and so on.
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Metal finders' more accurate term is: Metal Detectors, as the metal detector's main function is to detect the presence of metal objects including for example underground buried metal targets such as gold treasures, bronze statues, archaeological artifacts made of different metal types.
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The most common type of metal detector is a hand-held metal detector or coil-based detectors that use a oval-shaped plastic disks with built-in coils made of copper usually, the search coil works as sensor probe and must be swept or moved over the ground to detect the potential metal targets buried underground, when the search coil detect a metal object the device give a feedback as an acoustic feedback as changed audio tone via speaker or earphone, and in most metal detectors the feedback is an analog or digital indicator as a unique number called Target ID based on target metal type.
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These metal detectors first invented and manufactured commercially in United States of America in twentieth century by Fisher Labs in 1930s then other companies like Garrett established and developed the metal detectors in terms of technology and features in following decades to reach the current form of metal detector that is common in use by hobbyists and treasure hunters or gold prospectors.
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Skilled prospectors have put their confidence in American metal detectors due to the high quality of their industry and low cost of production, they are known all over the world.
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American metal finders The history and development of metal detectors in the United States roots back to the end of the 19th century after a huge development and acquired knowledge during this century in the field of electrical engineering by a lot of scientists and inventors.
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Many inventors and engineers tried to invent or manufacture a working device to detect or pinpoint the presence of metal objects depending on electrical and related magnetic theories and researches.
D
First idea Many scientists, academics, and gold miners started experimenting with the idea or concept of creating a device that could locate metal hidden underground after the widespread adoption of electrically-powered appliances in the mid 1800s. A device like this would be very useful to the many prospectors still searching for gold after the "Gold Rush," period , making the first person to perfect a metal detector extremely wealthy.
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Gustave Trouvé, a French electrical engineer, invented the first metal detector in 1874. He created a hand-held device in order to locate and separate bullets and other metal objects from human patients.
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Following the assassination of American president James Garfield in 1881, Alexander Graham Bell - the inventor of telephone - attempted to create a metal detector similar to Gustave Trouvé's device. Graham Bell used his unit to try to locate the fatal bullet inside President Garfield's body. Bell's metal detector worked, but the metal coil springs of James Garfield's bed threw the detector off, and the search for the bullet failed.
D
Despite the fact that the first metal detector failed to save the 20th President of the United States, Alexander Graham Bell's system was a viable metal detector, and it served as the blueprint for all subsequent metal detectors.
D
These machines were initially very large, complex, and operated on vacuum tubes , however, they were useful, and as a result, their popularity grew. Most notably, after world war these early metal detectors were used to locate and clear landmines and unexploded bombs throughout Europe.
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Technology development
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Gerhard Fischer
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Gerhard Fischer developed a portable metal detector in 1925. Fischer's model was first marketed commercially in 1931, and he was responsible for the first large-scale hand-held metal detector development.
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Gerhard Fisher studied electronics at the University of Dresden before immigrating to the United States. When working as a Research Engineer in Los Angeles, California, he came up with the concept of a portable metal detector while working with aircraft radio detection finders. Fisher shared the concept with Albert Einstein, who foresaw the widespread use of hand-held metal detectors.
D
Dr. Gerhard Fisher, the founder of Fisher Research Laboratory, was contracted by the Federal Telegraph Company and Western Air Express to establish airborne direction finding equipment in the late 1920s. He received some of the first patents in the area of radio-based airborne direction finding. He came across some unusual errors in the course of his work, and once he figured out what was wrong, he had the foresight to apply the solution to a totally unrelated area, metal and mineral detection."
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Fisher received the patent for the first portable metal detector in 1925, and in 1931, he marketed his first Fisher device to the general public, and he established a famous Fisher Labs company that started to manufacture and develop hand-held metal detectors and sell it commercially.
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Charles Garrett
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Despite the fact that Fisher was the first to receive a patent for a metal detector, he was only one of many who improved and mastered the device that is now found in your detector’s shops. Charles Garrett, the founder of Garrett Metal Detectors, was another key figure in the creation of today's metal detectors.
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Garrett, an electrical engineer by profession, began metal detecting as a pastime in the early 1960s. He tried a number of machines on the market but couldn't find one that could do what he needed. As a result, he started developing his own metal detector. He was able to develop a system that removed oscillator drift, as well as many special search coils that he patented, both of which effectively revolutionized metal detector design at the time.
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To present day
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In the 1960s, the first industrial metal detectors were produced, and they were widely used for mineral prospecting and other industrial purposes. De-mining (the detection of landmines), the detection of weapons such as knives and guns (particularly in airport security), geophysical prospecting, archaeology, and treasure hunting are just some of the applications.
D
Metal detectors are also used to detect foreign bodies in food, as well as steel reinforcement bars in concrete and pipes, as well as wires buried in walls or floors in the building industry.
D
The future of metal detectors is anyone's guess, given the large number of professional and amateur players involved, as well as the rapid speed of technical progress in general. Metal detectors, on the other hand, will almost certainly continue to grow and adapt in order to uncover even more treasure.
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Treasure hunters never give up, and as the history of the metal detector shows, it's these dedicated, creative individuals who have shaped metal detectors into the devices they are today, and who will continue to shape the future of metal detecting
D
Discriminators and circuits Transistors, discriminators, modern search coil designs, and wireless technology, all of which were developed in 1947 by John Bardeen, Walter Brattain, and William Shockley, have had a significant impact on the advancement of metal detectors as we know them today. Both of these factors, as well as others, have contributed to the metal detector's current status as a lightweight, compact, easy-to-use, deep-seeking system.
D
The invention of a tunable induction device was the most significant technological advancement in detectors. Two electro-magnetically tuned coils were used in this method. One coil serves as an RF transmitter, while the other serves as a receiver; in some situations, these coils may be tuned to frequencies ranging from 3 to 100 kHz.
D
Due to eddy currents induced in the metal, a signal is detected when metal is present. The fact that every metal has a different phase response when exposed to alternating current allowed detectors to differentiate between metals. Longer waves (low frequency) penetrate the ground deeper and select for high conductivity targets like silver and copper, while shorter waves (higher frequency) select for low conductivity targets like iron. Unfortunately, ground mineralization interference affects high frequency as well. This selectivity or discrimination allowed the development of detectors that could only detect desirable metals.
D
Unfortunately, ground mineralization interference affects high frequency as well. This selectivity, or discrimination, allowed the development of detectors that could detect desirable metals while ignoring undesirable metals.
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Even with discriminators, avoiding undesirable metals was difficult because some of them have similar phase responses (for example, tinfoil and gold), particularly in alloy form. As a result, tuning out those metals incorrectly increased the chance of missing a valuable discovery. Discriminators also had the downside of lowering the sensitivity of the devices.
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Manufacturers and companies Since the beginning of the invention of the metal detector and its commercial sale, many manufacturers of metal detectors were established during the twentieth century in the United States of America.
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These companies provided dozens of new products and various multi-purpose metal detectors suitable for all prospectors categories from beginners to professionals, and these companies contributed to the development of device technology and its features. By providing improvements and additions to the general design of metal detectors.
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Fisher Labs
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History Dr. Gerhard R. Fisher, the world-famous engineer and inventor who was the first to obtain a patent for the metal detector, founded Fisher Research Labs in 1931. Fisher Research Labs is a made-in-America success story that began in Fisher's garage and has grown from there.
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Fisher Labs, the world's oldest metal detector company, uses cutting-edge technologies to create some of the industry's most reliable devices.
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Dr. Fisher was a Research Engineer in Los Angeles in the late 1920s when he received the first patent for aircraft radio direction finders. He was a German refugee who studied electronics at the University of Dresden. Dr. Albert Einstein was impressed with his groundbreaking work in aviation. Dr. Einstein expected the widespread use of radio direction finders in the air, on land, and at sea after seeing a demonstration of Fisher's equipment.
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Fisher Research Labs was built in Fisher's garage in Palo Alto, California, in 1931. He and four coworkers created the "Metallascope," a tough, user-friendly metal detector. It was an ungainly unit, with two wide, flat wooden boxes containing basic copper coils, five vacuum tubes, and a few assorted parts, by today's standards of lightweight handheld detectors. The Metallascope quickly captured the nation's and, within a brief period, the world's imagination.
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To meet the increasing demand for the Metallascope, also known as the M-Scope, Fisher Labs relocated to a small building at 745 Emerson St. in Palo Alto in 1936. Dr. Fisher received a patent for his invention not long ago. For all forms of electronic metal detection, the M-Scope became the agreed standard.
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It was used by geologists to find ore, fortune seekers to find treasure, service companies to identify underground tubing, timber mills to detect metal inclusions in sawn logs, and law enforcement to discover lost and concealed weapons.
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Fisher relocated to a larger apartment in Palo Alto in 1939, shortly before World War II, at 1961 University Ave. Fisher Research Labs was called upon to devote its scientific expertise to the war effort during World War II and the Korean Conflict, but the M-Scope industry was never ignored.
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Fisher Labs relocated to a new manufacturing plant in Belmont, California, in 1961. Dr. Fisher's reputation and career had left an indelible imprint on the world of electronics by the time he retired in 1967. Fisher Research Labs expanded and relocated to Los Banos, Calif., in 1974, where it remained until 2006, when it was purchased by First Texas Holdings Corporation.
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First Texas relocated the firm to El Paso, Texas, where it continues the Fisher tradition of scientific breakthroughs redefining the state of the art of metal detection. Fisher's vast range of brands, which have the finest ergonomics, most streamlined user interfaces, and innovative ground balance and objective separation capabilities, are the result.
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Technologies developed Fisher was the pioneer in metal detection technology and it is the first to introduce new innovations and technologies in metal detection , treasure detection and security products.
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The company invented or enhanced existed technologies in electromagnetic engineering to get a best devices in term of performance and If you're looking for hidden utilities, security walk through metal detectors, or long-buried treasures, Fisher technology can get the job done quickly. Fisher efficiency and creativity are your trustworthy source for underground finding devices, from analog to digital, in single or multiple frequencies.
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Search Systems
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Search systems in Fisher’s metal detectors include multiple search technologies that rely on electromagnetic technology including VLF , Pulse Induction and other derived technologies for detection of metal using a special features for metal discrimination through signal based Target ID or acoustic output based on metal type .
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Some devices incorporate a mechanism to select predefined settings known as search modes or detection modes that offer a different system for multiple purposes and conditions based on ground terrain , soil type and other factors.
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Search coils developed
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F75
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F70
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5" DD Round White Coil - Item 5COIL-F75 6-1/2" White Elliptical Concentric Closed Coil - Item 6COIL-E 10" Concentric Elliptical Coil - Item 10COIL-F70 10" DD White Elliptical Closed Coil - Item 10COILDD-F75 11"DD Elliptical Open Coil - Item 11COIL-F75 15" DD Round Open Coil - Item 15COIL-F75
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F5
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5" DD Round White Coil - Item 5COIL-F5F 8" Concentric Open Coil - Item 8COIL-7TEK 10" Concentric Elliptical Coil - Item 10COIL-F5F 10" DD White Elliptical Closed Coil - Item 10COILDD-FRL 11"DD Elliptical Open Coil - Item 11COIL-F5F
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F4
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F2
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4” Round Black Concentric Coil-Item 4COILF 8” Concentric Coil-Item 8COIL-7BLKF 10” Concentric Coil-Item 10COILF 11" Elliptical Open Coil - Item 11COIL-F2F 11” DD Bi-Axial Black Coil-Item 11COIL-F4F
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F19
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5” DD Round White Coil-Item 5COIL-GBUG 10" DD White Elliptical Closed Coil - Item 10COILDD-FRL 11"DD Elliptical Open Coil - Item 11COIL-F5F
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Gold Bug / Pro / DP
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5” DD Round White Coil-Item 5COIL-GBUG 10” Solid DD White Elliptical Coil-Item 10COILDD-GB 11” DD Bi-Axial Black Coil-Item 11COIL-GB
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Gold Bug 2
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6-1/2” White Concentric Elliptical Coil-Item 6 COILE-7-GB2 10” White Concentric Elliptical Coil-Item 10 COIL-GB2 14” White Concentric Elliptical Coil-Item 14 COIL-7-GB
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F44
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4" Round Search Coil - Item 4COIL-FS 7" Round Coil - Item 7COIL-RE-F 9" Concentric Teardrop Coil - Item 9COIL-EE 11" Concentric Teardrop Coil - Item 11COIL-EE 11" DD Elliptical Coil - Item 11COIL-FRL 4" Coil Cover - Item 4COVER 7" Round Coil Cover - Item 7COVER-RE 9" Teardrop Coil Cover - 9COVER-EE 11" Coil Cover - Item COVER-11DD
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Bounty Hunter
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History and Establishing
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Metal detectors from the Bounty Hunter business are plain, fast, and inexpensive devices for the hobby of searching for gold and lost metal items such as rings, coins, and so on.
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The Bounty Hunter corporation is headquartered in El Paso, Texas, and its parent company, First Texas, comprises several metal detector manufacturers, such as Fisher Labs and Teknetics, as well as firms that specialize in other areas, such as night vision systems.
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Technologies They Developed
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The company produces a wide range of metal detector models with various features, including metal detectors for kids, coin shooting detectors for amateurs, and even gold prospectors metal detectors.
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All of the company's metal detectors use electromagnetic equipment, such as very low technology VLF with a search coil system, and they have a search area and a very shallow depth of less than 2 meters underground.
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Throughout its existence, the company has manufactured approximately 55 products, including various devices and related accessories in various models, as well as search coils for various purposes.
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Search Systems
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Multiple search technologies based on electromagnetic technology are available in Bounty Hunter's metal detectors, including VLF, Pulse Induction, and other derived technologies for metal detection using special features.
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Some systems provide a mechanism for selecting predefined settings called search modes or detection modes, which have a different method for different purposes and conditions depending on ground terrain, soil type, and other variables.
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Metal detectors for military uses The first metal detector, designed by Alexander Graham Bell, proved to be a practical metal detector, and it served as the prototype for all subsequent metal detectors.
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Initially, these machines were huge and complex, and they used vacuum tubes to operate.
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Nonetheless, it proved to be useful, and it grew in popularity among users and prospectors for specific applications.
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One of the early common uses of the first metal detectors, for example, was the detection of landmines and unexploded bombs in a number of European countries following the First and Second World Wars.
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Uses and benefits Metal detectors can be used if for several military uses, which can be summarized as follows:
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Exposing the mines planted in the fields during the war or after the end of the war Detect dangerous explosives and cluster bombs dangerous to people's lives Hand-held metal detectors can be used to search people for weapons and explosives
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War Mine Detection Demining, also known as mine removal, is the method of clearing a field of landmines.
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The aim of military operations is to clear a path through a minefield as quickly as possible, which is mostly accomplished using equipment like mine plows and blast waves.
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Humanitarian demining, on the other hand, aims to clear all landmines to a certain depth and make the land secure for human use.
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The process of finding or detection of mines done by a special designed metal detector exclusively developed to detect mines and bombs.
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Landmine detection techniques have been studied in a wide range of ways.
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Electromagnetic technologies are most popular, and one of them (ground penetrating radar) has been used in conjunction with metal detectors.
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Mine casings produce a cavity that can be detected using acoustic methods or sensors to detect vapor leakage from landmines. Rats and mongooses, for example, can walk safely over a minefield and detect explosives, and animals can even be used to screen air samples over possible minefields. Bees, plants, and bacteria may all be useful. Nuclear quadrupole resonance and neutron probes can also be used to detect explosives in landmines.
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Specially trained dogs are often used to focus the search and confirm that an area has been cleared, mines are often cleared using mechanical equipment such as flails and excavators.
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See also List of metal detecting finds
See also