Lrl from Italy

[daniel]

Thanks Nicolas!

[daniel]

I've built FrancoItaly's LRL2 from post 68. Instead of the stylus antenna I've used simple coil (like the one from FreePDK). See the attached photo.

I don't have buried metals but did test with TV and it works from 4 meters away and through concrete walls! Potentiometer P3 is super sensible but if adjusted well then if target is recognized it starts to blink. Maybe with a precision multiturn potentiometer it will be easier to adjust.

PS. With stylus antenna it does not react to TV.

[Nicolas]

Hi Daniel nice job and work. Use multiturn for precision is so better. And try to use ferrite coil with frequency 75khz is so better for gold
My congratulation

[FrancoItaly]

Hi daniel,
The test with the tv is not significant, my lrl with stylus antenna practically does not react to any signal, if not very close, but feels the phenomenon. I repeat once more that needs to be done tests with metals buried at least 1 month.
Regards

[mustefa ubram]

HI FRANCO
HOW ARE YOU DEARE FREIND?
What is the minimum and maximum voltage output in ic1a?
what is voltage range in output ic1a?

[daniel]

Did tests today with buried metal (Iron rods that are over 30 years buried) but no signal at all. Tried both antennas stylus and mono coil. Nada nothing :-( thats a bit of frustrating. Only TV and fluorescent lamps works.

I 've also put a variable capacitor for stylus antenna C11 (5 - 27pf) to see if something changes but its the same it doesnt work for me.

Anyone here with positive results? Did you found something buried with this LRL? Im very interested because maybe I build something wrong.

[mustefa ubram]

Hi freind.
i think frnco told this lrl working only for non magnetic metals same copper or solver.dont work for magnetic metal

[Geo]

Franco do you remember how much is the signal at emitter of TR1 at schema with xtal 8Mhz??
I constructed a new ground plane pcb but something is not going right.

Regards

[FrancoItaly]

Hi Geo,
The important thing is that there is a signal at the output of TR1, about 2V - 5V, as I mentioned with the quartz disconnected there should be no DC voltage signal at the output, and with quartz connected you need to choose C2, C3, C4 for a DC signal (about 2-5V). The best solution is a double-sided PCB with the lower face connected to ground and with the components soldered on the top face.
Regards

[mustefa ubram]

Originally Posted by mustefa ubram

HI FRANCO
HOW ARE YOU DEARE FREIND?
What is the minimum and maximum voltage output in ic1a?
what is voltage range in output ic1a?

franco please reply to this post

[FrancoItaly]

Hi Mustefa,
If you refer to PLL schematic we have IC2A, not IC1A and the important thing is that at PIN 2 of IC1 there is a DC voltage 1-6V (measured with a DC voltmeter, with scope we have an impulse segnal). The IC2A output must be regulated by P3 for better threshold.
Regards

[FrancoItaly]

Hi daniel,
As mustefa said the Lrls do not respond to iron target and this is a good luck... For me it works well 2 or 3 turns for L1 with 22pF and this for my country and in Switzerland, you can try 4 or more turns but remember you must have a long time buried metal for test.
Regards

[FrancoItaly]

Hi mustefa,
I don't see IC1A, what it you're referring to?
Regards

[mustefa ubram]

Originally Posted by FrancoItaly

Hi Mustefa,
If you refer to PLL schematic we have IC2A, not IC1A and the important thing is that at PIN 2 of IC1 there is a DC voltage 1-6V (measured with a DC voltmeter, with scope we have an impulse segnal). The IC2A output must be regulated by P3 for better threshold.
Regards

Hi franco my porpose is 8mhz crystal osilator tape lrl.i want out put voltage range in the pin 1 ic1a (358?
thank you very much

[Geo]

Originally Posted by FrancoItaly

Hi Geo,
The important thing is that there is a signal at the output of TR1, about 2V - 5V, as I mentioned with the quartz disconnected there should be no DC voltage signal at the output, and with quartz connected you need to choose C2, C3, C4 for a DC signal (about 2-5V). The best solution is a double-sided PCB with the lower face connected to ground and with the components soldered on the top face.
Regards

Hi Franco.
Thanks for your answer.
I made a double side pcb but i have the upper face connected to gnd, i think there is not problem. I adjusted the capacitors so to have a dc out of 4.1 v but when i touch the antenna the out goes up, don't lowers as you wrote at other thread. Who is your opinion?????

Regards

[FrancoItaly]

Hi Geo,
This case has never occurred in my lrls (I've built a dozen lrls) for some unknown reason your LRL works in reverse mode. Try it out on the field and see how it behaves with the phenomenon, basically touch the antenna is an empirical way to test the LRL.
Regards

[mustefa ubram]

Originally Posted by Geo

Hi Franco.
Thanks for your answer.
I made a double side pcb but i have the upper face connected to gnd, i think there is not problem. I adjusted the capacitors so to have a dc out of 4.1 v but when i touch the antenna the out goes up, don't lowers as you wrote at other thread. Who is your opinion?????

Regards

HI GEO
if you made lrl 8mhz tayp.Please measure the output of IC1a.I want the minimum voltage in stand by system and maximum voltage When it reacts.i want for connect to the micro?
thant you

[FrancoItaly]

Hi Mustefa,
The pin 1 of IC1A must be at a more low voltage of the connection point between R5 and R6, and in this way all the LEDs are off and this is achieved by adjusting P1. If you want a more soft regulation of P1 you have to add a resistor on the ground side and must be calculated in such a way that with P1 rotated fully clockwise to the first LED is lit and the buzzer is on. You have to remember that adjusting P2 (gain) varies the output of IC1A and then you must also adjust P1.
Regards

[mustefa ubram]

Originally Posted by FrancoItaly

Hi Mustefa,
The pin 1 of IC1A must be at a more low voltage of the connection point between R5 and R6, and in this way all the LEDs are off and this is achieved by adjusting P1. If you want a more soft regulation of P1 you have to add a resistor on the ground side and must be calculated in such a way that with P1 rotated fully clockwise to the first LED is lit and the buzzer is on. You have to remember that adjusting P2 (gain) varies the output of IC1A and then you must also adjust P1.
Regards

thank you franco
I want to connect the output voltage to the micro.maximum input voltage for micro is 5v.I want to know the maximum and minimum output voltage for potentiometer designed for voltage 5V.
please help me?
thank you

[FrancoItaly]

Hi Mustefa,
I think that the best solution is to power IC1 with 5V instead of 12V, adjusts the output of the sensor stage to approximately 2V and put one 5V zener to non inverting input of IC1A and ground.
Regards

[daniel]

Originally Posted by Geo

Hi Franco.
Thanks for your answer.
I made a double side pcb but i have the upper face connected to gnd, i think there is not problem. I adjusted the capacitors so to have a dc out of 4.1 v but when i touch the antenna the out goes up, don't lowers as you wrote at other thread. Who is your opinion?????

Regards

Have the same problem with LRL2 sometimes it goes in reverse mode. Seems like it has to do with signals around you. To avoid that I turn Pot3 all the way down and only then I power up the cirucit. I wait 10sec for it to settle down.
Now I turn Pot3 up until the LED lights up. Then I turn it a little bit down until the LED goes off. Now I can move around and find my TV in 4 meters distance :-) and LED goes on.

If I go very very near to the TV then sometimes it goes in reverse mode and LED goes out when it finds the TV. Seems like if the signal is to high it switches in reverse mode.

[Geo]

Thanks daniel.
I use LRL3 with other display schematic so i can't try what you say.
Maybe a good box with shield to be a good solution

Regards

[mustefa ubram]

hi franco
please see
The closed circuit opamp non-inverting and And increasing the voltage method.Why in practice it does not work?When the maximum is rv4 voltage output is 10/5 volt .By touching the pin base of transistor2 voltage decreases to 0.5 V.why?I thought that the sense phenomenon on the output voltage increases linearly
What is Duty rv4?Please explain about class opamp?

[FrancoItaly]

Hi mustefa,
I cannot open your file, are you referring to 5Volt modification?
Regards

[mustefa ubram]

Originally Posted by FrancoItaly

Hi mustefa,
I cannot open your file, are you referring to 5Volt modification?
Regards

hi franco
I did not modify to 5volt.I want to change the output voltage from 0 to5
please explain about opamp class and rv4 in this scematic?