Description
TDI SL
TDI SL from American company White’s is a powerful multi-purpose electromagnetic metal detector for various applications including gold prospecting, coin shooting and relic hunting.
The Pulse Induction technology available in TDI SL is developed to guarantee a best detection performance of different metal types and more depth in comparison with VLF metal detectors.
TDI SL Features
Applications & Uses
TDI SL device considered a versatile metal detector as it can be used for different purposes including for example:
- Natural gold prospecting, it can find gold nuggets and gold veins
- Coin shooting including ancient or modern coins made of silver or bronze or gold.
- Detect ferrous metals like iron, steel and so on.
- Find ancient relics and artifacts like jewellery such as rings-collars…
Detection Technology
TDI SL use a powerful reliable Pulse Induction technology for detection of possible metal objects buried underground like small coins, relics or jewellery.
In Pulse Induction there is one electric coil used in the search head (coil), it acts as a transmitter and receiver at the same time.
The coil sends powerful, short electrical pulses, each pulse generates a very tiny magnetic field. When this pulse is fades away, the polar magnetic field reverses and suddenly collapses, this electric current lasts for several microseconds, so it causes an electrical current to flow through the coil which lasts about 30 microseconds.
Then another electrical pulse is sent and the process is repeated a number of times (2600 beats per second).
When this flow of pulses collides by a buried metal object such as a coin, a magnetic field is generated in the metal body, the reflected pulses and the current passing through the coil are determined by a metallic target and the user is alerted by sound tones.
Ground Balance
One of the main features of the TDI SL is its ability to achieve the ground balance of the mineralization value of the ground while maintaining the depth provided by the use of pulse induction technology.
This is achieved using a differential technique where two of the dissolution samples are compared. The ground balance is adjusted by adjusting the values so that the two samples have the same response, thus eliminating the ground signal.
Adjust Settings Using Controls
TDI SL includes a set of keys, knobs to control different settings related to current and pulse generation for fine-tune of detection process.
Included controls are as following:
– Frequency
This control allows adjustment of the pulse rate, it used to reduce the effect of any electronic interference that may be caused by external electromagnetic sources.
– Power / Gain
It is used to control the power level of the received signals.
This knob key increases or decreases from 0 to 10 of the signal amplification value, and is used to turn the device on or off (when the value is 0)
– Threshold
It is used to control the volume of the audio tone
– Pulse Delay
This knob key allows control of the pulse delay time, which is the time period between two pulses, and the key values vary between 10 and 25 microseconds
– Target Conductivity
This multi-value key provides three options:
– High – Only
– Low Only
– All Target
– Ground Balance
It is a circular key with 11 values (OFF to 11), which is used to manually control the value of the ground balance as explained previously
Search Coils
TDI SL uses a patented dual-field DF search coil that gives the user two different coils simultaneously. The first and largest is the external coil suitable for the most deep-seated targets, while the inner and smaller one is more sensitive to the small objects.
As an example, a DF coil measuring 12 inches for outer coil and 6 inches for inner coil can capture very small gold nuggets
Also, the (7-inch -3.5-inch) coil is even better to pick up smaller gold nuggets while not sacrificing depth.
