Metal detectors from the perspective of an experienced amateur radio operator
A few months ago, in a normal conversation with his nephew, the conversation went about metal detectors, treasure hunters and other similar things. I, as a radio amateur with experience, was very affected, at first glance, very profitable, an idea that was not new for a long time, but still very relevant. Therefore, he promised to investigate this issue in more detail.
Started to "dig" first on the Internet. It turned out that there are many organizations of treasure hunters, a whole world has been created, which thousands of people live in. Everything is complicated and simple at the same time. If you know what you want, you can immediately decide who you are - with professionals or with amateurs.
I was interested in the purely technical side of things. The complexity of the equipment, the cost and the possibility of self-manufacturing. A lot of reviews and analyzes posted on the sites gave a detailed picture, which I tried to summarize and lay out at your discretion, with the expectation that many can derive some benefit from the information received.
I would like to start, of course, with professionals. Serious firms like Fisher or Garrett produce a rather wide range of metal detectors (or metal detectors); prices usually range from 40 thousand rubles, as, for example, for the Minelab Eureka Gold detector for searching for gold nuggets.
Up to 8 thousand rubles for the simplest of the Garrett models - ACE 150
There are significant differences between different models according to their main capabilities, for more expensive models this list is huge, I’m citing the basic data:
In the “All Metals” mode, objects can be detected at a considerable depth.
Determination of the type of metal by the difference in sound.
A special sound signal from the coins.
High-level microprocessor control.
You can configure the discriminator for a specific type of metal.
On a graphical scale, you can determine iron, silver and gold.
There is the possibility of measuring the size of the object, its depth, while at the same time indicating the location on the display screen.
Setting the balance of the soil both manual and automatic.
Voice message about the characteristics of the last detected target.
I will not add about the availability of various accessories and connectors - this is understandable by itself. It is interesting that for your money you can buy a device of any configuration, supplement the model with a depth enhancer, for example, TreasureHound EagleEye for GTI 2500 ,
which allows to significantly increase the search depth.
The reviews are quite interesting, but the price of the product confuses. In order to buy it, you need to have considerable experience in treasure hunting, therefore I considered the option of self-production.
In a short review I will not broadly describe the theoretical aspects of electrical processes in circuits, I will try to simplify the theory for a better understanding of a wide range of readers.
It is known from physics that metals have a certain electrical and magnetic permeability, that is, when a metal is placed inside an electric coil, its inductance changes - if the metals are magnetic, like iron, the inductance increases, if you take brass, the inductance decreases. Most of the simplest metal detector circuits are built on this physical dependence.
I tried it practically - the circuit works, it detects metal objects, but, alas, a lot of shortcomings: low sensitivity, there is no way to accurately determine the type of metal, the work is unstable, although large pieces of iron can be successfully detected at a depth of up to a meter.
The second physical principle is the reflection of an electrical signal from metal surfaces. Simplified operation of devices of the type TR / VLF:the transmitter emits a signal with a frequency usually from tens to hundreds of kilohertz, the receiver receives reflected.
The returned signal determines the presence of metal and the distance to it. Advantages - a more accurate search for metals, greater sensitivity, better stability of the circuit. Disadvantages - complex circuitry, the problem with the manual manufacturing of a high-quality working coil, the difficulty of setting up the circuit to the required quality of work.
After checking and reading, I came to the same conclusion as many other lovers:
For fun or when searching for metals in a particular place for personal purposes, not for profit or sports interest, it’s enough to make a simple scheme and use it to look for large pieces of iron lying in the ground since the Second World War or scrap metal buried by an excavator from a collective farm from the times of the Soviet Union . The cost of such a scheme will be within a few hundred rubles.
If you want to engage in large-scale metal detection and, hoping to have either profit or exciting adventures, it is better, naturally, to get a good device from a normal company. In this case, a completely new mysterious world will open before you, where you can discover many underground secrets and take part in various expeditions. The price of such pleasure is from 8 to 40 thousand rubles .
Well, didn’t you want to try the taste of adventure?
Started to "dig" first on the Internet. It turned out that there are many organizations of treasure hunters, a whole world has been created, which thousands of people live in. Everything is complicated and simple at the same time. If you know what you want, you can immediately decide who you are - with professionals or with amateurs.
I was interested in the purely technical side of things. The complexity of the equipment, the cost and the possibility of self-manufacturing. A lot of reviews and analyzes posted on the sites gave a detailed picture, which I tried to summarize and lay out at your discretion, with the expectation that many can derive some benefit from the information received.
I would like to start, of course, with professionals. Serious firms like Fisher or Garrett produce a rather wide range of metal detectors (or metal detectors); prices usually range from 40 thousand rubles, as, for example, for the Minelab Eureka Gold detector for searching for gold nuggets.
Up to 8 thousand rubles for the simplest of the Garrett models - ACE 150
There are significant differences between different models according to their main capabilities, for more expensive models this list is huge, I’m citing the basic data:
In the “All Metals” mode, objects can be detected at a considerable depth.
Determination of the type of metal by the difference in sound.
A special sound signal from the coins.
High-level microprocessor control.
You can configure the discriminator for a specific type of metal.
On a graphical scale, you can determine iron, silver and gold.
There is the possibility of measuring the size of the object, its depth, while at the same time indicating the location on the display screen.
Setting the balance of the soil both manual and automatic.
Voice message about the characteristics of the last detected target.
I will not add about the availability of various accessories and connectors - this is understandable by itself. It is interesting that for your money you can buy a device of any configuration, supplement the model with a depth enhancer, for example, TreasureHound EagleEye for GTI 2500 ,
which allows to significantly increase the search depth.
The reviews are quite interesting, but the price of the product confuses. In order to buy it, you need to have considerable experience in treasure hunting, therefore I considered the option of self-production.
In a short review I will not broadly describe the theoretical aspects of electrical processes in circuits, I will try to simplify the theory for a better understanding of a wide range of readers.
It is known from physics that metals have a certain electrical and magnetic permeability, that is, when a metal is placed inside an electric coil, its inductance changes - if the metals are magnetic, like iron, the inductance increases, if you take brass, the inductance decreases. Most of the simplest metal detector circuits are built on this physical dependence.
I tried it practically - the circuit works, it detects metal objects, but, alas, a lot of shortcomings: low sensitivity, there is no way to accurately determine the type of metal, the work is unstable, although large pieces of iron can be successfully detected at a depth of up to a meter.
The second physical principle is the reflection of an electrical signal from metal surfaces. Simplified operation of devices of the type TR / VLF:the transmitter emits a signal with a frequency usually from tens to hundreds of kilohertz, the receiver receives reflected.
The returned signal determines the presence of metal and the distance to it. Advantages - a more accurate search for metals, greater sensitivity, better stability of the circuit. Disadvantages - complex circuitry, the problem with the manual manufacturing of a high-quality working coil, the difficulty of setting up the circuit to the required quality of work.
After checking and reading, I came to the same conclusion as many other lovers:
For fun or when searching for metals in a particular place for personal purposes, not for profit or sports interest, it’s enough to make a simple scheme and use it to look for large pieces of iron lying in the ground since the Second World War or scrap metal buried by an excavator from a collective farm from the times of the Soviet Union . The cost of such a scheme will be within a few hundred rubles.
If you want to engage in large-scale metal detection and, hoping to have either profit or exciting adventures, it is better, naturally, to get a good device from a normal company. In this case, a completely new mysterious world will open before you, where you can discover many underground secrets and take part in various expeditions. The price of such pleasure is from 8 to 40 thousand rubles .
Well, didn’t you want to try the taste of adventure?