Lrl from Italy

[liudengyuand]

In this circuit, if the crystal frequency uses 100MHz, which requires changes, because the 100MHz frequency is very high, I think we should pay attention to the filtering of the capacitor

[mc_307]

hello guys, i have a problem. led1 is not working at all. led2 and led3 are working, buzzer is working. I replaced lm358 and led, but still not working..

[FrancoItaly]

Originally Posted by mc_307

hello guys, i have a problem. led1 is not working at all. led2 and led3 are working, buzzer is working. I replaced lm358 and led, but still not working..

If the buzzer works, the led that is connected to the same point must also work, check the value of R9, perhaps it is wrong.

[mc_307]

Originally Posted by FrancoItaly

If the buzzer works, the led that is connected to the same point must also work, check the value of R9, perhaps it is wrong.

I connected 22k resistors in series to p1, but I don't have 560k and 56k resistors. 220k and 150k connected. Could the problem be caused by this? also led1 connected to ic2b r7. When p1 and p2 are fully open, all the leds are on and the buzzer beeps. I made the single coil crystal one. I guess I need to find 560k and 56k resistors. Are these values so important? Are there close values?

[Sally]

Hi Franco, I'm a newbie here. I will try to build your 8mhz crystal detector and thank you for sharing your design here in this forum. I do not know if it works here in my country somewhere in South East Asia. Hopefully it will and serve the purpose. Will update you soon. Thank you.

[liudengyuand]

Should be joined .Acc circuit

[liudengyuand]

AGC

[kaveh]

Hello to all friends , I want to use the mpsa18 transistor in this circuit. Is there no problem? Thank you

[FrancoItaly]

Originally Posted by kaveh

Hello to all friends , I want to use the mpsa18 transistor in this circuit. Is there no problem? Thank you

I think if you use it with a gain greater than 500 it is fine.

[liudengyuand]

I think we should change the power supply, using a single lithium battery voltage, 3V to supply the whole system without the need for too much bulky battery

[ERDOGAN37]

https://www.youtube.com/watch?v=C1LQ1oayuzwl

[humhum]

Originally Posted by ERDOGAN37

https://www.youtube.com/watch?v=C1LQ1oayuzwl

Coungratulation Friend .

[ERDOGAN37]

[FrancoItaly]

I placed again a 20Mhz version which proved unstable, but simply by changing the quartz from 20Mhz to 14Mhz it became stable, I have verified this with two lrls. This is basically the original 8Mhz version in which I changed the value of the quartz and added several trimmers to facilitate the tuning. By adjusting C10 it is possible to find a point where the signal increases considerably, a sign that it is tuned on a harmonic and this increases the sensitivity of the lrl. You can also try other frequencies, for example 15 Mhz, 16 Mhz, 17Mhz or others. I haven't been able to test on the field yet.

[brain]

As soon as the phenomenon catches the sinus amplitude value, there is growth. I saw this in the trials at 110 mhz. I will send you by franco size at 110 mhz. I used your circuit.

[brain]

by franco can you tell us what is in your test area as metal and what is the depth?

[FrancoItaly]

Originally Posted by brain

by franco can you tell us what is in your test area as metal and what is the depth?

Unfortunately I no longer have a field where to do the tests, there is only a point on my ground where there is a good signal, I don't know what is buried there. I use this place where I do comparative tests.

[liudengyuand]

I suggest that you change the 3.3 volt air supply voltage, you can use a lithium battery to do power

[Sally]

Hello Sir Franco, I had sent an email to you regarding phenomenon. If you have time please i need your reply.

Thank you,
Sally

[Jeg]

Hi Franco
I would like to ask you what is the frequency range approximately in the tank circuit of L1 and C10.


ps. By the way, L1 is a 3T air core coil. What is the diameter of the core?



Best regards

[FrancoItaly]

Originally Posted by Jeg

Hi Franco
I would like to ask you what is the frequency range approximately in the tank circuit of L1 and C10.


ps. By the way, L1 is a 3T air core coil. What is the diameter of the core?



Best regards

I think the frequency is around 100Mhz and the coil diameter is 10mm.

[Jeg]

Originally Posted by FrancoItaly

I think the frequency is around 100Mhz and the coil diameter is 10mm.

Thanks a lot Franco.

[kaveh]

Hello Mr. Franco and dear friends Why does the circuit of some friends sense iron? What is the reason? Wishing the best for you and everyone

[FrancoItaly]

Originally Posted by kaveh

Hello Mr. Franco and dear friends Why does the circuit of some friends sense iron? What is the reason? Wishing the best for you and everyone

According to my experience my lrl is not sensitive to iron, but I also believe the other lrls, I believe that iron is not able to generate or in some way affect the phenomenon, but it is just my personal idea.

[Jeg]

Originally Posted by Babak51

This design and circuit of Mr. Franco, which has been slightly strengthened by our good friends, and of course it is much better to increase the distance of the sensor from the discipline. However, it is very powerful and sensitive.

Hi babak
Is that possible to share the circuit that corresponds to that board of yours? I dont see any Ic's in original franco's circuit. Thanks