Information verified by experienced users (including Badger) who have had Koschey in their hands for more than 7 years and with the device they are not only hobby friends, but also work mates.
RULE #1 I recommend turning on MD + adjusting the maximum depth + doing ground balance in THREE PLACES every 7-15 meters (kind of like a triangle) and see indicators M:? and F:?, (holding the coil at the lower position 2 cm from the ground).
CONDITIONALLY INDICATORS “M: from 0 to 500” enable the desired filter in PARAMETERS. CM. TABLE No. 1
AFTER AUTO BG (automatic ground balance) in 3 places (it will be like this No. 1 = F: 86.5, No. 2 = F: 87.4, No. 3 F: = 83.9), maybe from “F : 80 to 92"; edit in manual BG taking as a basis ONE highest indicator “F:” and it is for US F: 87.4 and in Manual BG reduce it by 3 (three) units. = 84.4. AND THIS WILL BE THE GOLDEN MEAN, ACCORDING to the BG on our MD in that exact place and WE WILL RECEIVE THE MINIMUM LOSSES IN THE GROUND!
TABLE No. 1. CORRECT CHOICE OF FILTER after Soil Balance.
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For KOSCHEY K-20M, 25K |
For KOSCHEY K-20T, 25Turbo |
For KOSCHEY X-45 (4-frequency) |
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Recom.FG=1 |
Recom.FG=1 |
Recom.FG=1 |
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Recom.FG=2 |
Recom.FG=2 |
Recom.FG=2 |
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Recomm.FG=3 |
Recomm.FG=3 |
Recomm.FG=3 |
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Recom.FG=4 |
Recom.FG=4 |
Recom.FG=4 |
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Recomm.FG=5 |
Recomm.FG=5 |
Recomm.FG=5 |
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IN 70% OF CASES, ACCORDING TO USER REVIEWS, THEY USE FILTER TWO (FG:2) |
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M:- indication of mineralization. FG– soil filter, which is recommended to be set in the parameters.
Self-taught! You can also select a filter "at random" and without BG indicators. The principle is the same as with the threshold P:7 or 5 for adjusting the depth of md. On FG: 1 we drive in the air - “silent”. We begin to move the coil in a clean place above the ground 1-3 cm - if the VDI shows nothing, then we work on the first one, and if there is a reaction to the ground and the VDI shows the VDI in colored sectors - then RAISE Filter G: to the filter on which there is no reaction on the ground (Set a depth threshold at which you will not confuse false positives from interference with ground reaction. And one more thing, for those with MD 25K, don’t forget that AUTO BALANCE should be set to 6 when selecting a filter, and after selecting a filter, you can lower this value until there is no reaction to the ground... personally, from my observations I I don’t lower it below 4x, although there are craftsmen who say that they work at “zero”) And don’t forget that the more FG, the less depth in the air - BUT NOT IN THE GROUND!”
FROM MY EXPERIENCE ON WHICH SOILS WHAT FILTERS:
- Sand, dry peat, dried leaves layer with 15cm+ - suitable FG:1
- Virgin black soil with grass without oranca or dried oranica - suitable FG:2
- Chernozem, a plowed field or garden where there is little debris, especially on wet soil after a good rain or in the spring, and also where there are frequent clay/chernozem transitions - suitable FG:3
- A plowed field near a river bank, a wet field or with fertilizers, a temporarily drained pond (river) - suitable FG: 4. I also often use the 4th filter in places heavily littered with ferrous metals and oxides from them, such as a yard or a trash can, etc. Stable against interference from power lines, railway lines, telephone towers, transformers, etc. Don't forget that when you turn on. FG:4 – THEN YOU CAN IMMEDIATELY GO TO THE DEPTH ADJUSTMENT and lower the THRESHOLD lower by one, or even two divisions.
- FG:5 Suitable for salty areas of soil, for example, the sea or where there is strong interference or the best and clearest VDI discrimination is needed, then paired with algorithm No. 1 is what is needed.
RULE #2 What FREQUENCY do you need on your metal detector? Koschey supports frequencies from 5 to 12 kHz. The key to success is the CORRECT SELECTION OF FREQUENCY for your locations. “Keep in mind that, in general, all types of targets can be detected at all frequencies. BUT, if we have a settlement according to the Cheka, then why do we need a frequency of 9 kHz at which we will dig targets up to 15-20 cm. in the ground, if we can work at 12 kHz and dig those same targets at 20-30 cm. “Who drives on summer tires in winter when they have winter tires?”
- Metal plastic, search for jewelry, small coins, products made from various bronze alloys - I recommend 11-12kHz.
- Copper and silver (including denarius) coins of medium and large size - I recommend – 7-8 kHz.
- Aluminum and nickel alloys as casings and coins of the USSR – 9-10 kHz.(suitable for medium-mineralized soil)
- Search for large coins or items made of silver, bronze, copper or war - 5-6.5 kHz.(suitable for highly mineralized soil)
Considering that Koshcheya has a ground filter, mineralization does not greatly affect the device. And to sum it up, if you don’t know what you’re looking for, take the most universal frequency from 7.4 to 8.3 kHz.
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For a beginner on wet soils where there is a lot of debris with a 15DD or larger coil. (for example, a vegetable garden) |
Universal setting for all coils and medium or lightly littered areas |
The deepest program, but also noisier on the ground, when hitting branches there are more triggers and a large spread in discrimination |
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P: 5-6 |
P: 5-6 Profile: T:2 |
P: 5-6 |
Instructions for beginners:
Setting up the K25K and K25T pulse mode:
How does adjusting soil balance affect depth:
Today we will talk about metal detectors of the Koschey brand (company). Let's look at the 5I model a little and see how to make it with your own hands.
A little history:
Koschey is not a scary skeleton at all. As with pirate, it is an abbreviation. The name comes from the first two letters of the last names of the developers - Kolokov and Shchedrin. Both from different countries, both engineers, collaborated and created a line of excellent metal detectors. Now their detectors are sold in parts (boards, blocks), in the form of construction kits and in finished form. But many radio amateurs want to assemble it not from a construction set, but with their own hands, with minimal investment.
What is 5I and what does it mean?
Koschey 5I is a pulsed universal metal detector. This device automatically adjusts to various sensors, apparently for this reason and universal. It began to be assembled at the beginning of 2007, based on experiences in the manufacture of previous models - Koschey 2I and Koschey 4IG. A distinctive feature of the 5I model is the LED indication, after which its modernization appeared - Koschey 5IM, with a display. Actually, they differ in display, the characteristics and other parameters are the same.
Some technical characteristics of this model:
- Mass – no more than 2 kg (with sensors 20 cm) and no more than 2.4 kg (with sensor 1.2 by 1.2 m).
- The length of the rod is adjustable, from 80 to 140 centimeters.
- Search mode – static.
- Indication – visual and audio.
- Multi-tonality is present.
Continuous operation time (1.3 AH battery):
- Economy mode – up to 15 hours.
- Normal mode – up to 8 hours.
- Accelerated (turbo) mode – up to 5 hours.
Depth characteristics (20 cm coil):
- Coin 2.5 cm – up to 29 cm.
- Medium-sized object – up to 1 m.
- Maximum depth – up to 1.5 m.
With a depth coil, the detection depth reaches 3 meters.
A little about the interface:
Koschey 5I has a fairly simple interface. 6 diodes - for indication, two toggle switches, a button and a trimming resistor. It’s not enough, but this is all it takes to set it up.
Koschey metal detector diagram
Below you see a diagram of this device. You can purchase it or assemble it yourself.
Koschey 20M is a selective resonant metal detector operating on the IB principle (Induction Balance). Koschey 20M has a high search depth (coin up to 35 cm, with an average coil size), as well as great customization capabilities (filters, balancing, mask settings, etc.) - this allows it to be classified as an average or even professional level metal detector.
A big PLUS of Koschei 20M Compared to other metal detectors, its “omnivorous coils” - it is able to work with coils from most branded metal detectors: Garrett, Fisher, Minelab and others makes it an almost unique metal detector. And also, in Koschey 20 as well as in Koschey 18, there is a set of tools for self-made search coils.
Like other metal detectors from the Koschei company, Koschey-20M is sold both as a finished metal detector and in the form of kits for assembly(Screen and keyboard board), or separately its electronic unit. If you had another metal detector before, then you can use the rod and coil from it for Koshchei 20. Or buy only the electronics and make the coil yourself. This will allow you to save big! In general, Koshchei-20M has its serious advantages!
Technical parameters of the Koschey 20M metal detector:
Operating principle diagram— VLF;
Operating frequency– from 4 to 10 kHz and depends on the search coil and the capacitor installed in the block. There are also Koschey 20M assemblies, where “craftsmen” install several capacitors and a switch, and call it multi-frequency. Such a modification only reduces the stability of the device and its reliability, but does not provide any operational advantages!
Metal detector power supply– 3.7..7.0 volts ( Optimal nutrition from 6 volt batteries or 4 AA batteries).
Metal discrimination– 20 groups;
Visual indication– LCD screen;
Sound indication– multi-tone (each sector corresponds to a specific tone of the sound identifier);
Search depth with standard 20cm ring coil:
- USSR 5 kopeck coin – up to 36 cm;
- Helmet – up to 1 meter;
- The maximum detection range is 2 meters.
Electronic unit Koschey 20M:
Unlike its predecessor Koschey 18M, Koschey 20M received a more powerful processor and has significantly fewer parts.
The block diagram of the Koschey 20M metal detector is as follows:
At the time of writing, Koschey 20M is equipped with firmware 2.05.
Various updates and beta firmware versions are regularly released for Koschey 20M. Beta versions are designated by letters (2.05A, 2.05b, 2.05g, etc.), but these updates are not final and may cause problems with the operation of the metal detector and are intended for testing by enthusiasts. Further, successful solutions are being implemented in new firmware versions (there is already an announcement of the release of firmware 2.06)! To receive a firmware update for Koschey 20M, you need to write to the developers (Developers website - metdet.ru) and indicate serial number your metal detector, then they will send you updates for it!
Materials for setting up, assembling and making the Koschey 20M metal detector with your own hands:
Connection diagram for the Koschey 20M metal detector board:
How to make a broadband coil for metal detectors Koschey 18M and Koschey 20M When connecting such a coil, it is necessary to remove the resonant capacitor from the circuit, and you will be able to change frequencies without changing the coil. But the use of such a coil also reduces its detection range -
How to make a resonant coil for the Koschey 20M and Koschey 25K metal detectors —
Connecting coilsNEL for metal detector Koschei 20M –
Connecting coilsMARS for metal detector Koschei 20M —
Coil connections fromGarrett for the Koschey 20M metal detector —
Connecting coilsFisher for the Koschey 20M metal detector –
Connecting coils from metal detectorsWhites for the Koschey 20M metal detector–
Also based on metal detectors Koschey 20M and Koschey 25K are assembled and underwater metal detectors . Sealing the electronic unit and search coil. But for successful work on the sea coast, it is still necessary to overcome salinity. Salt is known to be a conductor and VLF metal detectors often react to wet, salty soil as if it were metal. To neutralize this effect, a special underwater sensor has been developed for the Koshchei, which you can purchase separately.
Connecting an underwater printed sensor to the Koschey 20M and Koschey 25K metal detectors –
Conclusion: Koschey 20M has good search characteristics and great customization capabilities. This makes it a very interesting option in its price range of metal detectors, and the ability to buy it as a kit for assembly has no competitors at all among devices of this level. But the possibilities of its settings and its “habits” can cause some difficulties for a novice user. Those who are used to Koshchei 20M really like it. But for beginners and users accustomed to working with other devices, the Koschey 20M may cause some difficulties at the initial stage.
When writing, materials from the developers’ website were used - http://metdet.ru
Alternative sensors for the Koschey-20M metal detector
Part 1: Wideband Concentric Sensor
Next, we connect the coils to the cable according to the diagram. Particular attention should be paid to the phasing of the coils when soldering the cable. The transmitting and compensating coils must be connected in opposite directions. For ease of perception, the diagram conventionally shows the beginnings and ends of all coils in the form of leads coming out of the coils in a certain direction. This is exactly how the ends of “real coils” should be oriented and soldered. The figure below shows how to connect the sensor using the Belsis BW7809PL S-VHS cable. However, now we do not need to chase the extremely low resistance of the cable cores, as in the previous model of our IB detector. Koschey-20M does not use reactive energy recovery in the transmitter circuit, so the cable requirements are significantly reduced - a cable core resistance of 1-2 Ohms is now quite acceptable. In terms of electrical parameters, any stereo cable or S-VHS cable with separate insulated shields is now suitable for us. The main limiter is now the mechanical properties of the cable - it must be strong enough and have an outer diameter of 5-7 mm for reliable clamping in the sealed lead-in.
We fix the coil leads using a small plasticine cylinder. In addition to fixing the leads, it plays another important technological role - in the future it forms the places where the wires exit from the potting compound. To do this, the blister form has a small cylindrical recess, which should be tightly filled by the lower end of the plasticine cylinder. The inputs of the winding wires into the cylinder should be located at the level of the horizontal surface of the blister-shaped plastic, and the outputs towards the cable desoldering should be above the level of pouring the epoxy resin.
Now we proceed to preliminary balancing of the sensor. First, in the “Options” menu item, set “Gain” to 8 and remember it by pressing ENTER. Next, place the sensor away from metal objects and turn on the “Path Calibration” service mode.
Let's look at the features of this mode in Koshchei-20M. In order for this mode to become available, you must be in the “Battery control” menu item (see operating instructions, link) and press the ↓ button at least 8 times. After this, we return to the main menu, press the ↓ button several times and make sure that we have an additional item “Path Calibration”. We enter it by pressing the ENTER button. On the screen we will see an image similar to the one shown below.
The ideology of adjusting the Koshchey 20M for various sensors is that one or several profiles are allocated for each sensor (one profile for each frequency in the case of a wideband sensor). Using the ← and → buttons, select one of 25 profiles and, by pressing the ENTER button, enter the setup mode.
As you can see, in Koshchei-20M this mode is significantly more intense than in the previous model. Let's take a closer look at the purpose of each element.
The number of the edited profile is displayed in the upper right corner. This is done so that this number is visible and we do not accidentally spoil another work profile.
At the top of the screen there are two scales X (above) and Y (below). These scales indicate the absolute level of the X and Y signals at the output of the synchronous detector. In a properly balanced path, these signals should be minimal. Those. Signal level indicators should be located near the central (zero) mark. Below them are two more scales ΔX (above) and ΔY (below). These scales indicate increments of the X and Y scales. The sensitivity of incremental scales is approximately 100 times higher than that of absolute scales. The increments are reset by pressing any of the navigation buttons (arrow). On the left under the scales there is an output stage current indicator. These five parameters (scales and current indicator) are designed to monitor the response of the metal detector. The remaining indicators are designed to set signal parameters. The parameter to be changed is selected using the ← and → buttons. The selected parameter is indicated by underlining. The parameter can be changed using the and ↓ buttons. Let's look at each parameter in more detail.
Parameter H(frequency) specifies the operating frequency in kilohertz in the range from 4.01 kHz to 9.95 kHz.
Parameter A(amplitude) specifies the amplitude of the output signal in arbitrary units. The value can vary from 0 to 99.
Parameter F(phase) specifies the phase of the output signal. Values can vary from 0.0 to 359.9 degrees.
Parameter A(amplitude) specifies the amplitude of the electronic compensation signal in arbitrary units. The value can vary from 0 to 99.
Parameter f(phase) specifies the phase of the electronic compensation signal. Values can vary from 0.0 to 359.9 degrees.
Now we will show with an example how to use all this for configuration. So, we connect the sensor to the device, turn it on, using the manipulations described above, make the “Path Calibration” menu item available and enter it by selecting profile No. 2 for editing.
First of all, using the navigation buttons, we change the value of the operating frequency. Let it be 4.01kHz. Next, we set the electronic compensation amplitude to zero. Its phase at this stage does not matter. We set the phase of the output signal within 150-170 degrees, and reduce the amplitude of the output signal to zero. Next, we begin to gradually increase the amplitude of the output signal, and monitor the behavior of the X and Y scales.
The winding data of the coils is selected in such a way that the compensating coil initially creates a slight excess compensation. In this case, the X and Y scales deviate to the right. And when you try to slightly lift the small coil above the form, this picture only gets worse. Those. In this case, the scales should not go to the left through zero. If, during the ascent, your scale readings nevertheless pass through zero, it means that due to errors in the diameters of the wires or mandrels, there was a slight undercompensation. However, in this case the sensor can also be balanced; this will be discussed below.
Let's look at a way to eliminate small overcompensation. To do this, we need to slightly remove the compensating coil from the receiving coil. We do this with the help of a wooden toothpick - we insert it under the turns of the compensating coil and slightly bend them towards the center. At the same time, we monitor the readings, trying to get a zero balance on both X and Y scales.
Because the wire of the compensating coil is quite rigid, the bent turns do not require additional fixation. Following the readings of the scales, we bend the required number of turns. If there are not enough turns of one sector between the thread ties for balance, move on to another sector. Having achieved readings close to zero at a certain amplitude of the output signal, we increase it and, if necessary, adjust the position of the turns. The maximum output amplitude value will be different for different sensors and different frequencies. In general, when independently experimenting with a new sensor, you need to observe the output signal using an oscilloscope and stop when the signal shape (sine wave) begins to distort. If we repeat our constructions, the situation becomes simpler - we will indicate the approximate values of the parameters that should be obtained. So, specifically for this sensor at a frequency of 4 kHz, the amplitude of the output signal should be increased until the output stage current reaches about 150 mA. In this case, the amplitude of the output signal will be within 45..50. Having achieved an unbalance on the X and Y scales of at least +80% using coils, the preliminary balancing can be considered complete. To remember the already configured parameters, press the button ENTER. A message will appear on the screen requiring confirmation.
Press again ENTER. Next, turn off the device, unsolder the cable and begin filling the coils with epoxy resin. For these purposes we will need approximately 100-110 grams of resin. At the end of the pouring, we bend the “tails” of the reinforcing tapes inside the “spokes” and leave the mold on a flat surface for 24 hours for the resin to harden.
After the resin has hardened, remove the casting from the mold. In this case, you don’t have to spare the shape - we cut it with scissors in the right places. We remove the plasticine, and through the resulting hole we pull the ends of the wires to the other side of the casting. The result is such an elegant and durable design:
Now the sensor needs to be shielded. For these purposes, we use conductive varnish based on nitro varnish and crushed graphite. You can buy this varnish on the radio market or make it yourself. Let us recall the technology of its manufacture. We will need nitro varnish (for example, NTs-218 or NTs-243) and graphite powder. Graphite powder is sometimes sold at hardware stores. You can also make such a powder yourself by grinding electrical graphite brushes. To prepare conductive varnish, you need to mix nitro varnish and graphite powder in approximately equal volume proportions and mix the resulting mixture thoroughly.
The next stage is coating the sensor body with conductive varnish. In this design, it is not the housing that is shielded, but the directly embedded coils. Using a brush, coat the “small ring” with varnish. Don’t forget to install a grounding terminal - a small piece of multi-core insulated wire, one end of which must be cleaned and “fluffed”, and then lubricated with conductive varnish. For convenience, this conductor can be pre-fixed with a drop of hot-melt adhesive. Attention: The transmitting coil in this sensor does not need to be shielded!
After applying the varnish, the sensor must be dried for several hours and then the quality of the screen must be checked. To do this, you need to connect one of the tester probes to the copper conductor, and press the second one tightly to various points of the screen. The tester in resistance measurement mode should show resistance from hundreds of ohms to a few kiloohms. If this resistance is greater, it means that the varnish contained too little graphite powder. In this case, it is necessary to add graphite to the varnish and re-varnish the body.
Next, we proceed to placing the sensor inside the housing. We screw the pressure seal to the bracket. It is advisable to fix the pressure seal nut with some kind of glue or compound. Then we pass the end of the cable through the sealed gland.
Now we bend this end of the cable and lay it tightly inside the bracket, then securely fix it with hot glue.
Next we proceed to preparing the housing covers. On the top cover, use side cutters or a scalpel to remove four bosses (blue arrows). Then we drill six holes with a diameter of 3 mm and countersink them with a 6-7 mm drill for the screw head (green arrows). Then we drill a hole with a diameter of 7-8mm for the cable (red arrow). On the bottom cover we only remove the bosses. We don’t throw away the buds; we’ll need them later.
Next, we thread the end of the cable into the hole on the cover and screw the bracket using 3x16mm stainless steel screws. In the area of the “ears” of the bracket, to increase the strength of the connection, you can use 3x20mm or 3x25mm self-tapping screws. Attention: self-tapping screws must be stainless. They, unlike conventional steel ones, do not lead to imbalance of the sensor.
Next, insert the sensor inside the top cover of the case and see what we got:
Now we need to fix the sensor inside the top cover of the housing. To do this, lift the sensor and apply hot-melt adhesive inside the housing in the places shown by arrows. The hot melt adhesive must be well heated. Then press the sensor tightly against the lid. Where the cable exits (blue arrow), the glue should protrude inward and seal the hole around the cable. We orient the ends of the cable along the bottom of the resulting “bath” into which the finishing fill will be made, fixing the terminals of the windings. Regarding hot melt adhesive, we would like to draw your attention to the fact that “not all washing powders are equally good” :-). TOPEX hot melt adhesive has proven itself very well. Unlike cheap brands of glue, it gives a very reliable connection to polystyrene and epoxy casting.
Next, solder the ends of the coils to the cable according to the diagram given above. Please note that when using the BW7809PL (or similar) cable, the coils are shielded only along the “ground” wire of the receiving coil. And the shield of the conductor connected to the transmitter is not connected to ground in this connection. Therefore, you need to ensure that when installing in the connector and sensor, these screens do not touch each other!
We connect the sensor to the device, enter the “Path Calibration” mode for profile No. 2 and check the balance. Now we will need to pay special attention to the leads from the thicker wire that are soldered to the cable. The position of these pins significantly affects the balance! Therefore, they need to be laid in the optimal way. These terminals are most sensitive to balancing when placed next to the receiving coil. The direction of installation also matters. It depends on which direction we are moving - overcompensation or undercompensation. We monitor the readings of the scales and arrange the conclusions in such a way that the balance on both scales tends to zero. Considering that the dynamic range of the Koshchei-20M is several times greater than the range of the previous model, and also taking into account the presence of electronic compensation, at this stage a fairly large imbalance is acceptable on the X and Y scales - up to +80%. When laying, you also need to leave a small loop 1-2cm in size, which will rise above the surface of the “bath”.
Separately, we should dwell on the case when balancing using the existing “tails” does not work. In this case, one of the terminals should be extended with the same wire and laid around the perimeter inside the “bath”. This loop of wire plays the role of an auxiliary compensating winding. The direction of installation is determined by the readings of the scales. In case of severe unbalance, several such turns may be required. In this way, you can “treat” both overcompensation and undercompensation.
Next, place the sensor strictly horizontally and fill the “bath” with epoxy resin. After the resin has hardened, we check the balance again and, if necessary, correct it using the loop left above the surface. The loop must be pressed to the surface and bent in the optimal way, following the scale readings.
Now you can glue the bottom cover to the sensor. In principle, any universal glue will do for this. But the best results are obtained with homemade glue made by dissolving polystyrene in dichloroethane. For this purpose, the previously removed bosses will work for us. We place them in some kind of vial, fill it with a small amount of dichloroethane and seal it tightly. We wait until the polystyrene completely dissolves, which usually takes a couple of hours. Then mix the mixture and, if necessary, dilute it with dichloroethane until it becomes thick like sour cream. Attention: you need to work with dichloroethane in a well-ventilated area, because its fumes are poisonous! Next we start gluing. To do this, you need to carefully coat the grooves on both halves with glue and squeeze them tightly. It is important not to overdo it with glue so that its remains do not come out. By the way, one of the advantages of homemade glue is that it has the same color as the body. Therefore, small gluing flaws will be barely noticeable. You should also note that this glue dries quite quickly. Therefore, the lubrication process should not be delayed too much (no longer than 5-10 minutes).
So, as a result of all the work, we got this sensor.
And now it’s time to describe the capabilities of electronic compensation of the Koshchei-20M. This is a powerful tool that allows you to correct significant mechanical balancing errors. In fact, specifically for this sensor, everything that was described above regarding balancing loops, etc. in relation specifically to Koshchei-20M, this was done with great caution and is already optional :-). Electronic compensation can replace all this! However, it was very important information, which is needed to understand the general principles of balancing. It will also be useful to us when setting up other sensors, which will be described in the following articles.
So, let's finish balancing our sensor. If you diligently followed all the instructions, and after laying the loop the imbalance on the X and Y scales was less than +20%, then the balancing can be considered complete. However, if this cannot be achieved, for example, the imbalance turns out to be of the order of the allowed above +80%. Or, even worse - if the scales have gone into saturation, then it’s time to call for electronic compensation to help. You can enter it manually by changing the amplitude and phase of the compensation signal until zero readings are reached on the X and Y scales. However, this is too time-consuming and troublesome. Instead, you can use the auto compensation mode. To do this, just press the button while in the "Calibration path" mode. SEARCH MODE. After this, the message “Balancing:” will briefly appear on the screen, after which the device will again return to the “Path Calibration” mode. After this, the imbalance on the X and Y scales will become close to zero, and the amplitude and phase of the compensating signal will become different from zero. To assess the possibilities of auto-adjustment, let's analyze these numbers. For example, if the sensor had an initial scale misalignment of about 80%, then the amplitude of the compensation signal will be only about 4-7. Considering that the maximum amplitude of this signal can reach 99, we can draw conclusions about the possibilities of such compensation!
Now it is time to perform phase calibration of the path using ferrite. We hasten to please you - now this troublesome procedure is partially automated! So, we stock up on a small piece of ferrite (a ring or rod), place the sensor on some stand that does not contain metal fasteners (for example, a cardboard box) and press the button SOIL BALANCE. The following message will appear on the screen:
We remove all metal objects from the sensor, as well as prepared ferrite by 40-50 cm and press the button again SOIL BALANCE. The following message will appear on the screen:
We bring the ferrite closer to a distance of approximately 10-15 cm above the center of the sensor. If the ferrite is too close and the path is overloaded, the device will emit a warning sound. In this case, the ferrite must be removed from the sensor until the overload signal disappears. Then press the button again SOIL BALANCE. The following message will appear on the screen again:
Remove ferrite by 40-50cm, press SOIL BALANCE, after which the device returns to the “Path Calibration” mode. Using a piece of ferrite, we check the correctness of the calibration - bring it 10-15 cm closer to the sensor. Let us remind you that with correct phase calibration, when the ferrite approaches, the ΔX scale reading should remain unchanged, and the ΔY scale reading should deviate to the left! If necessary, we manually adjust the phase value of the output signal within small limits until such readings are achieved (usually this is not required).
If, after phase calibration of the path, the X and Y scales have moved apart (this can happen if, after auto-balancing, a relatively large amplitude of the compensation signal is obtained), repeat the balancing again by pressing the button SEARCH MODE. After this, the profile setup can be considered complete. Press the button ENTER and remember all the settings made.
Next, we repeat the setup procedure for two more frequencies and remember them in other profiles. The obtained important setting values are summarized in a table for your reference. Among them there is no data on the electronic compensation signal. These parameters may vary greatly for each specific case. Although, if you simply adjusted a ready-made sensor from Koshchei-18M to Koshchei-20M, then with a high probability it can be said that you did not need electronic compensation. This table also summarizes data on the detection depth of some typical targets (by air).
| Profile number | 2 | 3 | 4 |
| Operating frequency | 4.01kHz | 7.01kHz | 9.95kHz |
| Output current cascade (max.) | 153mA | 119mA | 80mA |
| TX amplitude | 48 | 84 | 99 |
| TX phase | 164.5° | 99.7° | 56.4° |
| Depth, pliers | 51cm | 42cm | 36cm |
| Depth, 5 kop. USSR | 29cm | 30cm | 25cm |
| Depth, copper penny Alexey Mikhailovich (scale) |
14cm | 15cm | 14cm |
conclusions
The main conclusion that can be drawn from the above is that Koschei-20M works perfectly with the wideband sensor from Koschei-18M. In this case, the detection depth of typical targets turns out to be comparable. However, the energy consumption of the new device is several times less - due to the lower supply voltage and due to lower current consumption.
Lower current in the sensor creates significantly lower field strength. This should have a beneficial effect on search depth in highly mineralized soil.
Now the user is much more free to choose operating frequencies. Although frequencies above 10 kHz are not yet available in the current firmware version.
The process of setting up sensors using Koshchei-20M is much simpler and more comfortable compared to the previous model.
To be continued...
In Russian fairy tales, an immortal hero named Koschey is inextricably linked with treasures, so it is not surprising that one of them present on the domestic market bears a similar name. Even if many users of expensive imported equipment think otherwise, in the price-quality category the Koschey (metal detector) is beyond competition.
This article gives the reader the opportunity to become more familiar with a remarkable device for searching for treasures. Review, characteristics, setup, diagram and owner reviews will help a potential buyer quickly navigate the specialized equipment market.
A short excursion
In fact, the connection between the metal detector and the fairy-tale character is not connected with hiding treasure and jewelry, but with the first two letters of the last names of the developers, Yuri Kolokolov and Andrey Shchedrin. The two mechanical engineers have been known among radio amateurs for many years. In addition to producing specialized equipment for metal detecting, they have also earned authority in instrument making.
Unlike foreign manufacturers of metal detectors, Russian scientists did not hide the operating principle of the devices they created and provided buyers with the opportunity to change the technical characteristics of the electronics. Metal detector circuit, detailed description basic structural elements and complete guide for setting up are included in the regular instructions that come with the device. It is precisely this attitude towards the future owner that attracts people to the device. a large number of potential buyers.
An ordinary miracle
To search for metal objects at shallow depths and in the walls of old buildings, an inexpensive pulse device is best suited. The Koschey-5I metal detector, costing about 5,000 rubles, can interest buyers who are purchasing such a specific device for the first time.
All functionality of this device is based on the operation of a microcontroller and a small program, and the simplicity of the design allows the owner to make modifications on his own, improving the sensitivity of the device as needed. Its operating principle is quite simple - the coil creates an electromagnetic field that changes its characteristics when passing through metal objects. The microcontroller analyzes the initial signal with the final value and provides the result to the user.
Convenience and simplicity
Cheap metal detectors have one unpleasant feature - the absence of a liquid crystal display. Naturally, the owner may have many questions regarding the setup of the device; the software part is especially interesting, which, according to the manufacturer, can be easily changed.
As practice shows, the problem can be solved in two ways: using a programmer and connecting the unit to personal computer. If everything is simple and clear with programming the microcircuit, then there are clearly questions about the second method. In the operating instructions, the manufacturer not only described in detail the method of connecting the metal detector to the X4 port, but also indicated the model of the adapter that the user will need to solve the task. In fact, you can connect to a computer not only a pulse metal detector, but also any other device that has the appropriate X4 interface.
Universal baby
It is clear that the concept “metal” can actually hide not only but also any debris made of steel or cast iron. Naturally, a treasure hunter will be interested in the possibility of identifying only treasures. It was for such purposes that the Koschey-20M metal detector was created. Peculiarity of this device is that the device can operate at 4-10 kHz, and accordingly the user himself is able to control the power
In addition to the basic characteristics necessary for searching for treasures, the detector has a lot of useful and useless functions. Firstly, the device is flashed at the software level, and on the manufacturer’s official website a selection of ready-made programs is available for precise operation under different operating conditions. The manufacturer did not skimp on the sound indication, installing full polyphony. But the ability to access the device using a PIN code only brings a smile to the treasure hunter’s face.
Light at the end of the tunnel
You should not expect the impossible from the device when purchasing. It doesn’t matter whether the metal detectors are expensive or cheap, the user will have to make fine tuning for each type of soil. Experts in this field recommend that beginners use the proven method with three coins (steel, bronze, gold), which must be buried separately to a depth of 20-30 centimeters.
Then everything is simple - by moving the circuit over the treasures and changing the frequency, you need to find out which sound indication corresponds to each metal to which the “Koschey” (metal detector) will react. As practice shows, at a frequency of 10 kilohertz, noble metals of gold and silver are perfectly detected, regardless of depth. The sound produced by the device is quite melodic and easy to remember. But to search for copper-based metals, it is better to shift it downward (6-7 kHz).
Strange modifications
Finds made by a metal detector sometimes turn out to be so valuable that many owners of the devices begin to feel dizzy - they have a desire to buy a more powerful and expensive device for searching for treasures. There is no need to rush to change the manufacturer; the developers have something to surprise the buyer. Based on the Koschey-20M device, there is an improved “Professional” version with a Goliath coil.
By maintaining the appearance of the metal detector, including the control panel and ease of use, the manufacturer managed to create a more powerful and sensitive device. Firstly, the device is capable of separating precious metals from ferrous ones at great depths, even if they are in close proximity to each other. The second advantage is the ability to operate the coil in the air, being above the surface of the earth at a distance of 5-10 centimeters.
All inclusive
Naturally, a Russian manufacturer must have at least one modification that can satisfy the wishes of even the most demanding customers.
The Koschey-25K metal detector is a kind of leader among all the manufacturer’s detectors. It’s better to start with technical characteristics that can really surprise future owners:
- The maximum object detection depth is 3 meters. Apparently, it is unlikely that a coin will be found under such a layer of earth, but the device will detect a tank from the Second World War or other large metal structure.
- Adjustable operating frequency ranges are 4-12 kHz and 400 Hz.
- Support for popular sensors: single-frequency, multi-frequency, pulse.
- Several search modes (selective, pulse, non-selective).
Needle in a haystack
The richer the functionality of the device, the greater its effectiveness in finding treasures hidden under a small layer of earth. Naturally, this is what attracts the attention of buyers to the Koschey metal detector, the price of which is in the range of 15-20 thousand rubles. True, few beginners know that in reality all the functionality will not be used by the user, because the universal device copes perfectly with the task and in one operating mode (we are talking about pulse search).
Therefore, before purchasing, it is better to consult with experts and decide for yourself what the buyer means by treasure. Some users need the device to search for lost jewelry near bodies of water, while others are interested in finding military graves. Definitely: there should be a serious approach to buying an expensive device.
Build quality and ergonomics
It cannot be said that the manufacturer paid much attention to the appearance of the device. Rather, on the contrary, being carried away by the functionality and efficiency of work, the engineers completely forgot about the build quality. In means mass media quite a lot of reviews regarding cheap appearance, which the metal detector has. Comparing the device with similar foreign devices, a significant difference is noticeable not only in manufacturing quality, but also in ergonomics.
However, during operation, the owner’s attitude towards the device may completely change. The simple design is reliable and practically indestructible when dropped or hit. Therefore, here it is up to the buyer to decide what is more important for him: to detect finds with a metal detector that has external beauty, or one that has increased strength.
Decent service
The domestic product is also interesting because in specialized markets Russian Federation the owner will always be able to purchase the accessories and spare parts he needs for his existing device. And you don’t need to think that the choice is limited to microcircuits and coils. On the counters you can see: housings for electronic units, brackets, handles, sensors and even modified circuits of all devices.
As practice shows, the electronic circuit of a metal detector and the search coil are the most popular elements of the device. After all, they are the ones who determine the effectiveness of the device. However, before purchasing spare parts, many experts recommend that the user first try changing the firmware of the metal detector, since often this is the action that allows you to configure the detector more effectively.
Comparison with analogues
In its price category, the domestic device has practically no competitors. In their reviews, enthusiasts often compare the Koschey pulse metal detector with a similar Fischer-2 device. It is not surprising that the Russian device wins in all tests, because, in fact, these are two completely different detectors that simply happen to be in the same price category.
Thus, “Fisher” is designed to search for small items made of non-ferrous metals and alloys at shallow depths (up to 30 cm). It has a low sensitivity coil and does not work over the air. And the “Koschey” (metal detector), on the contrary, is focused on great depths, large objects and is capable of operating in different frequency ranges. It is better to compare according to the stated technical specifications, and not in the price category.