Metal detector: Difference between revisions
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Archaeologists use metal detectors to scan their spoil heaps and also to examine wide areas such as [[battlefield|battlefield sites]] where surface scatters of metal objects may be all that survives. New metal detectors have small screens near the handle. |
Archaeologists use metal detectors to scan their spoil heaps and also to examine wide areas such as [[battlefield|battlefield sites]] where surface scatters of metal objects may be all that survives. New metal detectors have small screens near the handle. |
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==See Also== |
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The above is and archeological point and could be taken as to be seen biased. |
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[[UK Detector Finds Database]] |
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'''The veiw from a metal detectorists is that they are activly working and promoting the recording''' |
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The UKDFD[http://www.ukdfd.co.uk] is an initiative by members of the metal-detecting community to promote good practice within the hobby. It is an easy-to-use, friendly and supportive online facility for detectorists to record their finds and ensure that the information is preserved for future generations. |
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Those joining the scheme have immediate access to the database for uploading details of their finds, and simple instructions are provided at each stage of the process. A personal gallery is created for each user on entering their first record, which, as it grows, may be browsed or searched in the same way as a personal database. Items submitted are reviewed by the scheme’s own team of experts and full identification details are provided or confirmed as soon as possible. Users are also able to record their detector make and model, so that performance in different circumstances, and for different types of find, may be assessed. |
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'''MISSION STATEMENT''' |
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The UK Detector Finds Database ('''UKDFD''') is a hobby-based initiative, which has the following aims: |
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To promote a recording ethos within the hobby and encourage those detectorists who would not otherwise record their finds to do so by making use of the UKDFD self-recording facility |
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To bring about an increase in the number of detectorists recording their finds, and the overall number of items that are recorded |
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To make available a facility and encourage the recording of post c.1650 finds, many of which are not eligible for inclusion on the Portable Antiquities Scheme (PAS) database |
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To provide an easy-to-use and supportive self-recording environment for detectorists, which employs the latest technology and methods of communication |
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To make the UKDFD database accessible as an internet resource for the identification and research of items recorded, and to preserve that information for the benefit of future generations |
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==See also== |
==See also== |
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Revision as of 17:38, 31 March 2006
Metal detectors use electromagnetic induction to detect metal.
In 1881, Alexander Graham Bell constructed a crude metal detector in an attempt to find an assassin's bullet in President James Garfield. Gerhard Fischer patented a portable version in 1931.
Upright "archway" detectors are used at entrances to secured buildings, such as courthouses or airports, to detect metallic weapons which may be brought in. Small portable "wand" detectors are used by security staff to frisk persons for the same. Larger portable metal detectors are used by archaeologists and treasure hunters to locate metallic items, such as jewelry, coins, bullets, and other various artifacts buried shallowly underground.
There are three types of metal detectors: beat frequency oscillator, induction balance, and pulse induction.
- In a beat frequency oscillator detector, a coil is used as an inductor in an oscillator, whose frequency changes when metal causes its inductance to change. Another oscillator produces a close frequency, and audible beats between them signal metal.
- In an induction balance detector, there are two coils, usually gibbous with about 10% overlap, and a sine wave is transmitted with one coil and received with the other. The coils are adjusted so that there is no signal in the receive coil when there is no metal nearby.
- In a pulse induction detector, a pulse is generated (usually by cutting off an inductor) and sent through a coil and the detector listens for echoes.
Progressive metal detecting - Helping to understand our Past....
It worth noting that in countries where metal detecting is severaly restricted, such as Italy for example, incendents of the illegal artefact hunting with and without the use of metal detectors is causing untold damage to existing sites, with new sites and finds not being recorded.
One of the main causes of driving the hobby underground is the inability of some within the archaeological world to come to terms with what is after all a legitimate hobby and that it is the right of all of us to discover our own past and to record it with schemes such as PAS and the UKDFD for future generations to appreciate..
Thankfully there are enough enlightened archaeologists, now working with the metal detecting community, who appreciate the enormous contirbution that metal detecting makes to our knowledge of the past to ensure that those with an agenda to disrupt coorperation are also relegated to the past.
For find out more anout the hobby why not take a look at the UKs premier metal detcting forum :
http://www.forumukdetectornet.co.uk/phpBB2/index.php
Metal detectors and archaeology
The use of metal detectors to search for archaeological finds is practised both by archaeologists and hobbyists. In some European countries including France and Sweden the use of a metal detector is forbidden by law, unless one has special permission. This is intended to protect archaeological sites but rarely means that illicit metal detecting ('nighthawking') does not take place and has the effect that new sites found by metal detector are never publicised or investigated fully. Instead, they are slowly plundered for their metal items, disturbing the stratigraphy and forcing the artifacts on to the Black Market, never to be seen again. In the United Kingdom metal detecting is generally permitted provided certain criteria are met and efforts are made to record finds through the Portable Antiquities Scheme. The scheme has critics however, including some archaeologists and some metal detectorists themselves.
Countries with no restrictions or methods to deal with new finds in place are in danger of sites being regularly raided and their contents sold on without the information they provide ever being known. However, there are some responsible metal detectorists in unrestricted nations who contact archeologists when they find artifacts, and who never dig. They benefit archeology by finding artifacts for scientists.
Archaeologists use metal detectors to scan their spoil heaps and also to examine wide areas such as battlefield sites where surface scatters of metal objects may be all that survives. New metal detectors have small screens near the handle.
See Also
See also
External Links
- Coin Community Metal Detecting Forum - A free coin, currency, and metal detecting community. Novice collectors to experienced dealers gather here to share knowledge.