Lrl from Italy

[FrancoItaly]

Hello Mr. Franco. First of all, thank you very much. I need help with something? I tried to transfer your circuit. When voltage is applied, the yellow LED lights up and then goes out immediately. I can't see anything between the antenna and ground. I used BC183C LM358P 500k POT. Where exactly would the control points be?

The measurement to be made is at the output of the sensor stage R16/C18 (DC voltage) the other (1 LED) is out IC3A or (3 LEDs) out IC1A. in the new version with two tuning potentiometers it is still IC1A. 2 potentiometers allow for more precise tuning, furthermore the gain can be adjusted.

[osman34]

Is there a problem with the image?

[FrancoItaly]

I can't understand what you want to know. I can't tell you if your assembly is correct. First you need to calibrate the sensor stage to have a stable output, between 2V and 5V. Usually the instability is due to too much amplification. I recommend a double-sided pcb for the sensor stage, with the bottom connected to ground and another pcb, not critical, for power and display stage.

[kiro077]

Hello Mr. Franco. I need help please. The output voltage is 5.63V. When I touch the antenna the first LED turns off and the voltage drops. The transistors are BC550C with a gain of over 500. The problem is that I cannot get the effect of the compass and the sky.

[kiro077]

This is an 8 MHz version with 3 LEDs

[FrancoItaly]

This is an 8 MHz version with 3 LEDs

Compass effect and sky effect are unwanted effects, they appear if the sensor stage gain is too high, so the only remedy is to decrease it. If your lrl does not have this defect and the sensitivity to metals is good there is no problem. Of course I assume that you have calibrated the sensor stage to the limit of self oscillation.

[kiro077]

The problem is that on a test field it does not react to long-buried metal. Could you tell me how to calibrate the sensor stage to the self-oscillation limit.

[FrancoItaly]

The problem is that on a test field it does not react to long-buried metal. Could you tell me how to calibrate the sensor stage to the self-oscillation limit.

Do you have a field with metal buried for at least 2 months?

[omar]

Is there a problem with the image?

Yes, my friend Othman, there is a problem. Correct the location of the 33 nano capacitor connected to the 4148 signal correction diodes...


Note: Try the device with or without the protection diode on the voltage input and choose the best.

[kiro077]

Yes, the buried metals are over 7 years old. Where could the problem be? After all, the best test for the correct operation of lrl is to touch it with your hand and reduce the tension. Will you help me to make the new display with 3 potentiometers.

[kiro077]

Hello Mr. Franco. I need help, please. On a field with buried metal at 7 years old, there is no reaction. The antenna is spread over 90 centimeters and Gain at maximum gain. I can't get compass effect. What should I do?

[FrancoItaly]

Hello Mr. Franco. I need help, please. On a field with buried metal at 7 years old, there is no reaction. The antenna is spread over 90 centimeters and Gain at maximum gain. I can't get compass effect. What should I do?

Did you calibrate to have maximum gain but without self oscillation? Did you read the helps.txt I attached? The maximum sensitivity is walking from north to south, from west to east and vice versa is medium and from south to north is minimum, the signal increases as you get closer to the target, also above the target the signal is cancelled.

[kiro077]

Здравейте г-н Франко. Всичко съм изпълнил както е написано в helps. txt.
Изходното напрежение е 5.63V. Когато докосна антената, първият светодиод изгасва и напрежението пада. Ще ми помогне ли на усилването, ако направя дисплея с 3 потенциометъра или добавя
антенния усилвател?

[kiro077]

Hello Mr. Franco. I have done everything as written in the helps. txt.
The output voltage is 5.63V. When I touch the antenna, the first LED goes out and the voltage drops. Will it help my gain if I make a 3 potentiometer display or add
antenna amplifier?

[FrancoItaly]

Hello Mr. Franco. I have done everything as written in the helps. txt.
The output voltage is 5.63V. When I touch the antenna, the first LED goes out and the voltage drops. Will it help my gain if I make a 3 potentiometer display or add
antenna amplifier?

What values did you use for C2-C3-C4-C13-C14? Did you use a pcb only for the sensor stage? If you use a single pcb for the entire lrl, it may happen that the sensor stage starts to self oscillate with a lower gain, compared to the version with two pcbs. The antenna amplifier can be useful.