Lrl from Italy

[havoc88]

Originally Posted by walkman

Dear Franco which coil is right? or very sensivity

1. or 2. picture?

There is no "right" or "wrong" coil at least if both of them have three turns of wire plus there is no special reason to have vertical or horizontal position, only practical workspace on your pcb.

[k.hasanzade]

Dear franco
Thanks first for the design of the circuit that you design
I have a few questions
1. What is the reason for changing the circuit coil?
2. It is better not to install the first coil vertically and the second wire sheet horizontally؟
3.What is the new circuit calibration method?
best reguard
k.hasanzade

[FrancoItaly]

Originally Posted by taher5739

Sensitivity for gold or silver has increased, or both?
I want to know if adding the filter to the antenna amplifier section ,
Can make a distinction for copper or gold?
i wish you success in life

I buried silver and gold objects in my test field. Silver, buried for about 2 years, responds well, while gold, which has been buried for less than a year, responds little. In my previous test field (not here but in Italy and that I no longer have available) instead the gold responded well and it was a thin bracelet.
The amplifier antenna increases the sensitivity for all metals and I do not believe that the addition of a filter can be useful, however I did not do this test.

[FrancoItaly]

Originally Posted by havoc88

There is no "right" or "wrong" coil at least if both of them have three turns of wire plus there is no special reason to have vertical or horizontal position, only practical workspace on your pcb.

I agree, the coil is part of a resonant circuit and there is no risk of self-oscillation. In fact, if there were two coils belonging to two different stages and tuned to the same frequency, there would be this risk and placing the two coils perpendicular to each other would reduce mutual coupling.

[FrancoItaly]

Originally Posted by k.hasanzade

Dear franco
Thanks first for the design of the circuit that you design
I have a few questions
1. What is the reason for changing the circuit coil?
2. It is better not to install the first coil vertically and the second wire sheet horizontally؟
3.What is the new circuit calibration method?
best reguard
k.hasanzade

I refer to the antenna amplifier not to the antenna amplifier 2 which I suggest to build after the antenna amplifier.

1. The amplifier antenna increases the signal received from the antenna (let's call it phenomenon) and increases the total gain of the sensor stage which in some realizations may not be sufficient.
2. With the addition of the amplifier antenna there is always only one coil which is only moved.
3. The calibration method remains the same, only you have to do so before mounting the antenna amplifier. Subsequently the amplifier antenna is mounted and on the test field the 4.7K trimmer is set for maximum sensitivity.

[taher5739]

Originally Posted by FrancoItaly

I buried silver and gold objects in my test field. Silver, buried for about 2 years, responds well, while gold, which has been buried for less than a year, responds little. In my previous test field (not here but in Italy and that I no longer have available) instead the gold responded well and it was a thin bracelet.
The amplifier antenna increases the sensitivity for all metals and I do not believe that the addition of a filter can be useful, however I did not do this test.

Thank you so much Mr. Franco
We love you in Iran

[mc_307]

Hello my friends. 22k pot and 470k pot settings way? What Very good settings?

[FrancoItaly]

Originally Posted by mc_307

Hello my friends. 22k pot and 470k pot settings way? What Very good settings?

what are you referring to ?

[teo]

[teo]

franco is okay

[mc_307]

Originally Posted by FrancoItaly

what are you referring to ?

How to adjust potentiometer settings?

[FrancoItaly]

Originally Posted by mc_307

How to adjust potentiometer settings?

P1 (22K) is the threshold, it must be adjusted to have all the LEDs off, it also acts as a sensitivity control. P2 is the gain control, in the past I advised to change R1 (from 150K to 56K) and R2 (220K to 560K) to have more gain. To have a more precise threshold adjustment I recommend adding RA and RB. Their value depends on the output voltage of the sensor stage. The optimal value is when the first LED lights up with the maximum control.
If it is necessary to decrease RA (for example from 22K to 15K) increase RB (from 22K to 27K) in order to keep the divider value constant (Ra + RB + P1). Vice versa if it is necessary to increase RA.

[mc_307]

Originally Posted by FrancoItaly

P1 (22K) is the threshold, it must be adjusted to have all the LEDs off, it also acts as a sensitivity control. P2 is the gain control, in the past I advised to change R1 (from 150K to 56K) and R2 (220K to 560K) to have more gain. To have a more precise threshold adjustment I recommend adding RA and RB. Their value depends on the output voltage of the sensor stage. The optimal value is when the first LED lights up with the maximum control.
If it is necessary to decrease RA (for example from 22K to 15K) increase RB (from 22K to 27K) in order to keep the divider value constant (Ra + RB + P1). Vice versa if it is necessary to increase RA.

thanks..

Should the franco LRL box be combined with gnd? as in your message on page 12

[FrancoItaly]

Originally Posted by mc_307

thanks..

Should the franco LRL box be combined with gnd? as in your message on page 12

Yes.

[mc_307]

Originally Posted by FrancoItaly

Yes.

hello Franco;
I make your Lrl.

P1 1. pin 22k added, 3. pin 22k added.
Need to change r1 and r2? (R1 (from 150K to 56K) and R2 (220K to 560K) ?

[FrancoItaly]

Originally Posted by mc_307

hello Franco;
I make your Lrl.

P1 1. pin 22k added, 3. pin 22k added.
Need to change r1 and r2? (R1 (from 150K to 56K) and R2 (220K to 560K) ?

Yes, for more gain.

[taher5739]

hi dear Franco
I built your first circuit for curiosity But I have no voltage at the output.
my question is whether the bottom strips connected to ground circuit?
I have voltage in transistors 1, 2 and 3, but transistor 4 does not have voltage.
In addition i made your 8Mhz quartz oscillator circuit and works well
Thanks for your reply

[FrancoItaly]

Originally Posted by taher5739

hi dear Franco
I built your first circuit for curiosity But I have no voltage at the output.
my question is whether the bottom strips connected to ground circuit?
I have voltage in transistors 1, 2 and 3, but transistor 4 does not have voltage.
In addition i made your 8Mhz quartz oscillator circuit and works well
Thanks for your reply

In practice my lrl is a high gain amplifier for the 8Mhz signal mixed with the "phenomenon". If the quartz oscillator works properly the lack of signal at the output means that there is not enough amplification. Transistors must be of the BC183C or BC547C type or equivalent with a beta greater than 500. The amplification can be increased by increasing the value of C13 / C14 and decreasing R10 / R12. Before doing this you can increase C2 / C3 / C4 which establish how much signal will be amplified, you can only leave C2, or only C2 / C3 so as to have 1pF or 0.5pF respectively. Yes the bottom sideb is connected to ground, it is a screen to reduce the possibility of self-oscillation.

[taher5739]

Originally Posted by FrancoItaly

In practice my lrl is a high gain amplifier for the 8Mhz signal mixed with the "phenomenon". If the quartz oscillator works properly the lack of signal at the output means that there is not enough amplification. Transistors must be of the BC183C or BC547C type or equivalent with a beta greater than 500. The amplification can be increased by increasing the value of C13 / C14 and decreasing R10 / R12. Before doing this you can increase C2 / C3 / C4 which establish how much signal will be amplified, you can only leave C2, or only C2 / C3 so as to have 1pF or 0.5pF respectively. Yes the bottom sideb is connected to ground, it is a screen to reduce the possibility of self-oscillation.

Thank you so much Mr. Franco
But I think you did not understand me
I built two type of your circuit.
The quartz circuit works well But the non-quartz circuit (your first circuit, which 6 bars) does not output.
Transistors 1, 2 and 3 have voltages, but transistor 4 does not have voltage.
for oscillation(parasitic coupling) Do i connect bottom strips to ground ?
Thanks for your reply

[FrancoItaly]

Originally Posted by taher5739

Thank you so much Mr. Franco
But I think you did not understand me
I built two type of your circuit.
The quartz circuit works well But the non-quartz circuit (your first circuit, which 6 bars) does not output.
Transistors 1, 2 and 3 have voltages, but transistor 4 does not have voltage.
for oscillation(parasitic coupling) Do i connect bottom strips to ground ?
Thanks for your reply

In my first lrl (self oscillating) the lower strips are not needed, in fact the lower screen is used to prevent self-oscillations. I advise against using this version, I made the version with oscillator just to make the lrl less critical to build. One way to trigger the self oscillation is to use a lower strip to connect the collector of TR2 with the base of TR1 or between the collector of TR3 with the base of TR2 via an appropriate (small value) capacitor. In this way two points out of phase of 360 degrees are connected. The only possible advantage of this version is that with it you are sure to have obtained the maximum amplification. As I said in the past this lrl derives from a bug detector that auto oscillated providing a stable signal capable of revealing the "phenomenon".

[taher5739]

Originally Posted by FrancoItaly

In my first lrl (self oscillating) the lower strips are not needed, in fact the lower screen is used to prevent self-oscillations. I advise against using this version, I made the version with oscillator just to make the lrl less critical to build. One way to trigger the self oscillation is to use a lower strip to connect the collector of TR2 with the base of TR1 or between the collector of TR3 with the base of TR2 via an appropriate (small value) capacitor. In this way two points out of phase of 360 degrees are connected. The only possible advantage of this version is that with it you are sure to have obtained the maximum amplification. As I said in the past this lrl derives from a bug detector that auto oscillated providing a stable signal capable of revealing the "phenomenon".

Thank you so much Mr. Franco
Do you mean this
https://imgur.com/a/Zx5zjsE

"use a lower strip to connect the collector of TR2 with the base of TR1 via an appropriate (small value) capacitor"

[FrancoItaly]

Originally Posted by taher5739

Thank you so much Mr. Franco
Do you mean this
https://imgur.com/a/Zx5zjsE

"use a lower strip to connect the collector of TR2 with the base of TR1 via an appropriate (small value) capacitor"

Yes.

[alisuri]

Originally Posted by FrancoItaly

Yes.

Hi

I already built the original version of the LRL. The critical tests concerning voltages, touch ...
work well.
Is it necessary to impose the modifications like amplification.
Thanks
Ali

[FrancoItaly]

Originally Posted by alisuri

Hi

I already built the original version of the LRL. The critical tests concerning voltages, touch ...
work well.
Is it necessary to impose the modifications like amplification.
Thanks
Ali

In previous posts I suggested increasing R2 (from 220K to 560K) and decreasing R1 (from 150K to 56k) to increase the gain. Furthermore, to make P1 adjustment easier, 2 resistors (22K), one on the + 12V side and the other on the ground side should be placed in series with P1. The exact values of the 2 resistances must be found experimentally because it depends on the output value of the sensor stage (connected to the + input). If you increase the value of a resistance, you must also decrease the value of the other, so that their sum is in the range 30 - 50K. The ideal value is when P1 is set to maximum to the right, the first LED lights up and the buzzer sounds.

[alisuri]

Originally Posted by FrancoItaly

In previous posts I suggested increasing R2 (from 220K to 560K) and decreasing R1 (from 150K to 56k) to increase the gain. Furthermore, to make P1 adjustment easier, 2 resistors (22K), one on the + 12V side and the other on the ground side should be placed in series with P1. The exact values of the 2 resistances must be found experimentally because it depends on the output value of the sensor stage (connected to the + input). If you increase the value of a resistance, you must also decrease the value of the other, so that their sum is in the range 30 - 50K. The ideal value is when P1 is set to maximum to the right, the first LED lights up and the buzzer sounds.

Thank you very much for the suggestions.
Ciao