When I decided to write this blog with the title of ‘Learn Metal Detecting‘ I was well aware that these days a very popular leisure pastime is either treasure hunting for hidden objects such as coins and jewellery or fossicking for gold and other precious metals using a metal detector which operates by sensing changes in magnetic waves caused by metal. This leisure activity is made even more enjoyable when valuable finds are made!However ones chances of success are highly dependent on proper research on the best places to look together with a thorough understanding of the workings of a metal detector to ensure that the correct type is purchased for what it is you are searching for.
So if you are to ‘learn metal detecting‘ what type of metal detector should you be looking for as this could involve you in a big investment and a wrong choice could take the enjoyment out of your leisure pastime if you don’t achieve the results you were hoping for?
Let us look at the different types of metal detectors are what they are useful for:-
1. BEAT FREQUENCY OSCILLATION ( BFO )
This type is a simple device which is largely used by beginners because it is easy to operate and is relatively inexpensive. It operates using two wire coils, the oscillator creating a constant signal at a set frequency and the second coil detecting the interference of this frequency caused by metallic objects, which results in a changing audio tone. However this type of detector is unable to discriminate between signals coming from base metal objects such as cans and nails and more valuable gold and silver ones!
This is the most commonly used type having a wide range of uses and can detect a variety of different metallic objects. It operates using two round coils of wire. The coil on the outside is the transmitter which emits a low-frequency magnetic field onto the ground. If there is a metal object under the ground this will cause the magnetic field to be reflected. The other inside coil is the receiver which amplifies any magnetic reflections caused by a hidden metallic object resulting in an audio tone being played.
However as well as these two coils, a VLF metal detector also includes an electronic circuit used to filter the signal from the receiver. This is an important feature as the circuit is essentially a “tuner” that allows the user to ignore certain levels of signal and focus only on the desired range for the metals he is searching for. As different types of metal reflect different signals, a treasure hunter can ignore signals relating to aluminium and steel objects and concentrate on the more valuable ones such as gold and silver!
3. PULSE INDUCTION ( PI )
This is more specialized type of detector frequently used by treasure hunters because of its ability to locate objects at great depths. Only one coil is generally used on these devices, the coil sending out a magnetic field into the ground and any metal underground reflects the signal.However, a great advantage of the PI units over the other types of detectors described above is that it can quickly switch modes to “listen” for the reflected signal. Using a timed pulse method, the PI device can discriminate between signals it has sent and stray signals from surrounding areas. This makes PI detectors much more accurate but also more expensive.
You can see from the above the three main types of metal detectors that are used these days ranging in value from $100 to several thousand and from simple to complex! Your choice really depends on how seriously you take your leisure activity and how much you are prepared to invest in it.