Protek Gtx 711

[Geo]

Hello.
What is the technology behind this device? Is it effective?
Are the attached diagrams complete?
Because I noticed that the sensor transistor was disabled in the receiving circuit diagram. It needs a 150k resistor connected to the base to work. If there is any information or links that provide more clarification on this topic, please put them here.

Thank you.

Don't needs a 150k resistor, receiver works fine. Remember that although the antennas are vertical one to other the receiver takes a strong signal from transmitter and the first transistor is on. If Tx is off then the receiver is n't sensitive

[omar]

Hello Gio and thank you.
I am trying to understand the working principle of this device in detecting buried metals according to the philosophy of the designer of this circuit. Does it depend on the destructive interference between the transmitter signal and the reflected signal from the metal, which is in reverse phase, leading to the cancellation of the transmitter signal due to this destructive interference? Or is there something else it depends on? I read some comments on YouTube describing it as a failed attempt to detect buried precious metals. But who knows, maybe this device has been wronged.


Bahom,
I meant the first transistor in the receiving circuit. (Q1)

[Pahom]

Hello Gio and thank you.
I am trying to understand the working principle of this device in detecting buried metals according to the philosophy of the designer of this circuit. Does it depend on the destructive interference between the transmitter signal and the reflected signal from the metal, which is in reverse phase, leading to the cancellation of the transmitter signal due to this destructive interference? Or is there something else it depends on? I read some comments on YouTube describing it as a failed attempt to detect buried precious metals. But who knows, maybe this device has been wronged.


Bahom,
I meant the first transistor in the receiving circuit. (Q1)

According to the author of the scheme, it works and was created to work with different soil moisture. But this scheme is not complete. The author of the scheme is an amazing electronics engineer from Greece Andreas.

[omar]

Thanks Bahom.
The attached circuits in the topic work, there is no major problem...

I assembled the circuits and tested them individually on one breadboard I have. The transmitter circuit works but needs to adjust the inductance and impedance coils well to get good transmit power.
The receiver circuit did not work for me, it needed a resistor of 100k-470k connected between the potentiometer and the base of the first transistor. I faced a problem when adding an antenna to the receiver, the sensitivity dropped.

The problem was solved by operating the transmitter and receiver circuits from a single voltage source. The device can be operated on any crystal in the AM radio range. The lm741 can be replaced with a TL071....

Anyway, the circuit was confirmed to work and it works with a little attention. We need to verify the detection technique and its feasibility...

Note: This experiment was conducted to verify that the attached circuits work.

[Geo]

According to the author of the scheme, it works and was created to work with different soil moisture. But this scheme is not complete. The author of the scheme is an amazing electronics engineer from Greece Andreas.

No, Andreas has nothing to do with this schematic. I know the team of this project, very good electronic engineers....

[Pahom]

Thanks Bahom.
The attached circuits in the topic work, there is no major problem...

I assembled the circuits and tested them individually on one breadboard I have. The transmitter circuit works but needs to adjust the inductance and impedance coils well to get good transmit power.
The receiver circuit did not work for me, it needed a resistor of 100k-470k connected between the potentiometer and the base of the first transistor. I faced a problem when adding an antenna to the receiver, the sensitivity dropped.

The problem was solved by operating the transmitter and receiver circuits from a single voltage source. The device can be operated on any crystal in the AM radio range. The lm741 can be replaced with a TL071....

Anyway, the circuit was confirmed to work and it works with a little attention. We need to verify the detection technique and its feasibility...

Note: This experiment was conducted to verify that the attached circuits work.

It is very remarkable that you managed to launch the transmitter. Q11 what is the nominal value of the transistor

[Pahom]

No, Andreas has nothing to do with this schematic. I know the team of this project, very good electronic engineers....

Perhaps you are right. In one of the forum threads about Protek711 there was a dispute about who the author was and why this project was made publicly available. Perhaps I misunderstood.

[Geo]

At first version it has the name "Positron" and was working at 800 Khz. It had a lead battery and was very heavy. I have worked with most versions.

[Pahom]

At first version it has the name "Positron" and was working at 800 Khz. It had a lead battery and was very heavy. I have worked with most versions.

Geo, do you remember the rating of transistor Q11 on the transmitter diagram?

[Geo]

At this version Q11 ia a BD645.

[Pahom]

At this version Q11 ia a BD645.

Thank you! It means I installed the wrong analogue of the Russian transistor.

[omar]

Copied from YouTube...

The history of PROTEK begins in 1996, when a technician from the Czech Republic began experimenting with a range finder. He created a limited production of the device, which he named the PROTEK GTX 711. However, the product failed commercially because it did not meet the specifications necessary for reliable detection of valuables, leading to its failure to sell.

In the same year, a piece of equipment was found in the hands of a foreigner who ran a TV and radio repair shop in a basement in central Athens, in Omonia. He had the idea of copying both the circuitry and the appearance of the detector, with the aim of promoting it on the Greek market.
This attempt also failed, as the specifications were inferior, resulting in not a single unit being sold. At that time, a bankrupt dealer, facing financial difficulties, considered collaborating with the foreign technician to promote the failed PROTEK GTX 711 range finder using imaginative means and presenting it as a sophisticated detector.

[Geo]

Noooo...no.
This is the story that some guys try to give...
Protek is the same with Positron. Only the constructor of Positron knows exactly how to tune it.
There is n't nothing of Czech on this story.
Believe me.....

[omar]

Hi Geo.
I have been trying to understand the device's detection technology using a simple 480kHz crystal transmitter with a receiver.

It seems that the device relies on the change in impedance between the transmitting and receiving antennas and the change in capacitance when a physical object or electromagnetic field approaches the antennas. The antennas must be of a fixed length, the distance between them must be fixed, the operating voltage must be fixed, and grounding the circuit with the user's hand is important to minimize the device's impact on the user's body. The designer's philosophy is similar to two-box metal detectors.

There, magnetic induction is used, and here, radio frequencies are used. The effectiveness is unknown.

[Geo]

Hi Omar.
I believe the same with u.