Metal Detector Frequency Metal Detector Frequency | Definition and Examples

Metal Detector Frequency

Metal Detector Frequency

Metal Detector frequency in electromagnetic metal detectors is a value express a number

of sent electronic waves into the ground by the search coil, to detect buried metal targets.

The term Frequency in electronics is the number of waves per time unit (seconds)

and measured usually in hertz or kilohertz or KHz (more common in metal detectors)

For example: 20 KHz frequency of metal detector means that this device will send and receive signals 20000 times per second.

Electromagnetic metal detectors work according to several technologies, the most famous of which is

the very low frequency technology, which depends on sending electromagnetic signals resulting from electromagnetic

fields resulting from the passage of electric current within the coil towards the ground and then receiving

it a number of times corresponding to the frequency of the metal detector.

Metal detectors with VLF technology varies in frequency and typically the frequencies range between 3 – 100 KHz,

for example it is 61 KHz in Gold Kruzer, 45 KHz in Gold Monster 1000, 10 KHz in Garrett ACE 400i

Each of the frequencies has advantages, benefits, or drawbacks and disadvantages depending on the size,

depth and time of burial of the buried target, and factors related to soil and terrain in the detection area.

Low Frequency Metal Detector

Low frequency metal detector is the most common type of metal detector and is widely used due

to several advantages it provides, which we mention as follows:

  • Suitable for detecting larger buried metal objects such as golden chest or bronze statue
  • Better at receiving signals from target metal with high conductivity, such as silver
  • Detect targets at more depth in comparison with high-frequency metal detector
  • Less affected by interference or electronic noise caused in highly mineralized soils

But low-frequency metal detectors have disadvantages, including, for example:

  • Not suitable for detecting of smaller buried targets , example : tiny gold nuggets
  • Less suitable for low conductivity metal targets such as gold or iron

High Frequency Metal Detector

High frequency metal detector is a less common type of metal detector in comparison with

low-frequency metal detectors, but it has its applications and benefits

The advantages of using a high frequency metal detector can be summarized in the following points:

  • More suitable for detecting very small metal objects, with a small size not exceeding a few millimeters,

as an example of this is natural gold nuggets.

  • Better at receiving signals from target metal with low electrical conductivity, such as gold and iron
  • Greater accuracy in receiving target signals

However, high-frequency metal detectors have drawbacks, including, for example:

  • Detection of metal targets at a lower depth compared to low frequency devices
  • It is more affected by interference or electronic noise caused by highly mineralized grounds

Source : Metal Detector Frequency

Multi Frequency Metal Detectors

Multi frequency metal detectors are devices that incorporate technology that ensures

the use of more than one frequency in order to detect targets.

Some metal detectors, such as the Impact Pro, include multi frequencies for search, which are 5, 14 and 20 kHz,

and the user can switch between them according to his desire and the purpose of the search.

Recently, the synchronous multi-frequency technology has been invented, such as in the

Equinox device from Minelab with Multi-IQ technology, which includes a technology that allows the use of

several simultaneous frequencies in order to search for underground targets and this gives better coverage of

different types of minerals with different sizes small and large, as the prospector can choose one Frequencies

separately to search by it as in the Impact device.

multi IQ

We give prospectors interested in this technology a brief overview of multi-frequency metal detectors

Garrett ACE APEX

Garrett Ace Apex is a new innovative metal detector with new Garrett’s Multi-Flex technology

a multi-frequency feature for best detection performance and sensitivity.

User can use single frequency from 4 predefined frequencies (5 – 10 – 15 – 20 kHz)

or enable Multi-Flex feature for best performance and results.

Garrett Ace ApexMulti-Flex technology give the prospector a wide variety in detection applications for different types

of ferrous or non-ferrous metals and detection of buried objects at different sizes in all terrain and soil types.

Garrett ACE APEX combines modern design with a large screen with excellent performance,

excellent detection depth on a wide variety of targets, plus a fast target recovery speed and

a variety of practical uses that suit all the needs of prospectors and treasure hunters.


Impact pro metal detector from Nokta-Makro is a unique multi-purpose metal detector

high-performance device in all-natural conditions and terrain.

Within two years of its issuance, IMPACT proved its capabilities and reliability through

the experiences of prospectors and through real success stories such as the discovery of coins,

statues and ancient monuments by prospectors from different countries in the world.

Impact Metal Detector

The main important feature of the device is the Multi-Frequency technology, which was introduced

first in the device, which allows the use of one of three available search frequencies (5 – 14 – 20 kHz)

and switching between them when searching to suit the detection of different targets in various ground conditions.

In addition, the device has many features and functions to facilitate the work of prospectors and treasure hunters,

for example 12 different search modes for custom detection applications, the digital ID feature of the target

and the ignorance of specific range of metals as well as the cancellation of iron and special sound tones,

plus the economic price.


Equinox is a modern multi-purpose metal detector with a lot of features making it

a best companion for any prospector or treasure hunter.

The most innovative feature of Equinox, is its new Multi-IQ technology,

which allows the use of more than 5 different search frequencies simultaneously (5 – 10 – 15 – 20 – 40 kHz).

As a result, it is possible to search for underground metal targets using different frequencies

at the same time, which gives the possibility of covering various targets of different sizes and metal kinds.

This saves time and effort for the prospector and thus explores more targets in less time and thus yields greater returns.

Equinox Metal DetectorMetal Detector Frequency Chart

The search frequency varies between one device and another device, even from the same manufacturer,

which manufactures various devices with different frequencies to meet the demand of different categories

of prospectors and for various goals.

As explained previously, some devices contain multiple frequencies that can be used separately or activate

the simultaneous multi-frequency option.

In the following metal detector frequency chart, we list the search frequencies for a group of electromagnetic

metal detectors from different manufacturers.

Device Model Manufacturer Frequency Type Frequencies
TDI SL Whites Dual 2.6 kHz – 3 kHz
Impact Pro Nokta Makro Multi Frequency 5 – 14 – 20 kHz
Garrett ACE APEX Garrett Multi Frequency 5 – 10 – 15 – 20 kHz
Fisher F44 Fisher Labs Single 7.69 kHz
Garrett ACE 400i Garrett Single 10 kHz
Multi Kruzer Nokta Makro Multi Frequency 5kHz/14kHz/19kHz
Equinox Minelab Multi Frequency 5 – 10 – 15 – 20 – 40 kHz


Metal Detector Frequency for Gold

As for the best frequency for detecting gold, through a previous paragraph it was explained

that a high-frequency metal detector is better for detecting gold ore, especially and smaller sizes more accurately.

For example, the Gold Kruzer, which operates at the 61 kHz frequency, is specially designed to

detect the smallest nuggets of natural raw gold with high sensitivity, various modes, and a special mode for gold.

Best Metal Detector Frequency for Silver

The best frequency for detecting silver in a metal detector is the small frequencies range,

because silver metal is one of the metals with high electrical conductivity, and these frequencies are more suitable for it.

One of the metal detectors suitable for detecting silver is the Fisher F44, which operates at a frequency of 7.69 kHz

Metal Detector Depth Chart

Metal detector depth chart is a table that includes the maximum detection depths

that a metal detector can reach for different targets in terms of metal type

and size using different search coils.

In the following table, we mention an example of a metal detector depth chart

for the Pulse Nova device from OKM Germany

Search Coils Delta18 and Omega18 Search Coils Delta38 and Omega38 Frame Coil Xi104
Gold nugget ⌀ 5 mm 18 cm 17 cm Ignored
Gold coin ⌀ 20 mm 23 cm 25 cm Ignored
Gold ring ⌀ 22 mm 17 cm 34 cm Ignored
Silver coin ⌀ 24 mm 26 cm 35 cm Ignored
Silber coin ⌀ 40 mm 24 cm 43 cm Ignored
1 EUR coin 31 cm 44 cm Ignored
Beverage can 0,5 l 65 cm 110 cm 155 cm
Gas can 20 l 115 cm 180 cm 255 cm
Steel barrel DIN EN 210

115 cm

180 cm

310 cm


Metal Detector Circuit

Metal detector circuit is the electronic circuit consisting of a set of electrical

and electronic elements that together form a metal detector hardware parts.

The metal detector circuit consists of several basic components, including:

  • Power source: it is usually regular alkaline batteries for small devices,

lithium-ion batteries, or another type of battery for more advanced devices.

  • Power transmission wires or cables connect to the search coils, where the electric current

generated by the batteries is transferred within the search coils to generate the electromagnetic

fields used in metal detection.

  • The printed circuit board, which is a complex circuit that represents the heart of a metal detector,

where the signals reflected from underground targets are transmitted through coils and then wire

and coil cable to search for to be processed and analyzed.

This printed circuit is of a complex design and is made up of hundreds of different elements

commonly used in electronic circuits such as transistors, capacitors, diodes, resistors, coils,

and other elements such as a processor, memory, sensors, etc.

For more details see following article: Gold Detector Circuit

Professional Metal Detector Schematic

Professional metal detector schematic is an abstract schematic diagram that show

the components of the electronic circuit (transistors – capacitors – power source  …)

of a metal detector, the relationships and links between them, how to place them,

and basic information about them such as their electrical properties.


Metal Detector Circuit Layout

metal detector circuit layout is the schematic diagram of the circuit through specific symbols

that express the type of each element of the circuit, where each element

(resistance, capacitor, or diode, for example) has a specific symbol through which the specialist

in electronic engineering can read the drawing and know the links and specifications of the elements.

Metal Detector Circuit Diagram Free Download

Those interested in the subject of metal detectors and how to manufacture their circuits

can search through the Internet and download simple or complex circuit diagrams for electromagnetic metal detectors.

Some websites provide the possibility of free download of circuit diagrams in the form of

images or files of a special type for programs specialized in creating electronic circuits

Metal Detector Circuit pdf

Some websites also provide metal detector circuit diagrams in the portable document format PDF,

where the electronic circuit is detailed with high accuracy and suitable for printing on large size paper

in order to be used as a reference when building the circuit by electronic engineers.

Powerful Metal Detector Circuit Diagram

Most of the manufacturers of metal detectors surround their devices with a veil of secrecy

to preserve their rights and therefore do not make the electronic circuit diagrams

of their devices available to the public or for download through their website.



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