SBG-TR Metaldetector

[algan]

Hello Sasho, I would like to ask, have you tested this scheme in the field, what is the depth?

[scs-bg]

This is the detector with the greatest depth for medium and large objects. There is a small error in the circuit - D 3 is connected backwards. The coils can also be made with 0.25 wire. I did it a long time ago but I remember it worked great. The problem is who will dig...

[scs-bg]

The stabilizer can be replaced with LM 2930-8

[Ruben2000]

I built it once, but I wasn't successful!
On a forum, they mentioned that it's the most powerful detector in the world if you make a few component changes. I was very interested, but I didn't have the necessary experience to figure out what the problem was.
Since we're here with the master, he can help us with this.
I'm busy with other things now; I only check the forum occasionally.
I never thought I'd find Master Sasho on the Geotech forum with his alias scs-bg. It's a pleasure to meet him, even though we don't see each other. His words tell us what kind of person he is, and we thank him for sharing his knowledge and experiences with us.

[algan]

Thank you, Sasho, I'll have to get to drawing the circuit board and assembling it someday.

[scs-bg]

I don't know if it's the deepest, but it's really an excellent detector because it has a ground balance and works at a relatively low frequency. The only adjustment is the resonance of the coils. It has high sensitivity, but it works stably. If worn low above the ground, it reacts to metal eyelets on the operator's shoes.

[Ruben2000]

Perhaps that's the problem; I might be asking too much, but how can I tell if both coils are in resonance?
If I remember correctly, I calculated the inductance of L2 using C6 and C7 to match the frequency of L1, and I put the oscilloscope probe on pin 7 of the TL082 to balance the coils and made the waveform as small as possible.
Perhaps this configuration isn't correct!

[Ruben2000]

Thank you, Sasho, I'll have to get to drawing the circuit board and assembling it someday.

Here are some pictures of the PCB!

[scs-bg]

In resonance. It also determines the phase of the ground. The transmitting coil must be able to be tilted and fixed. Before starting work, a minimum of the received signal is established by rotating the transmitting coil and it is fixed in this position. This is shown in the general view with small arrows.( coil adjust)

[pechkata]

Nice to meet you, father Sasho.

My name is Nikolay from Levski station.
Life and health in winter we will continue with the projects.

[algan]

Here are some pictures of the PCB!

Thanks Ruben2000. Yesterday I etched the board according to the photo, I will have to follow it carefully. I made the correction for the diode that Sasho wrote, the rest will be exactly according to the diagram. I have ordered the transistors that are on the diagram and some other parts when they arrive, I will continue.

[scs-bg]

I made this detector 30 years ago. I have not seen anyone make a detector that actually works at a greater depth. And it turned out that there is almost nothing there. All interesting finds are at a depth of up to 40 centimeters. Valuables are hidden when there is a sudden danger. Then a person does not have the opportunity to hide them deep. That is why the place where you are looking is important, not the depth. And there are no unexplored places anymore....

[scs-bg]

I've wasted a lot of time making detectors as a hobby and I haven't gotten rich from it. It's a good thing I've always been at a high level in industrial electronics.

[scs-bg]

I've been here so far. I wish you health!