Lrl from Italy

[FrancoItaly]

I modified the help, in fact I realized that if the oscillator signal is too wide, it is difficult to set up as the signal reaches the base of TR2 also due to parasitic coupling.

[behnamvp]

crystal oscillator

good day

Mr.franco Italy
thank you for sharing project and helping others

don't know if someone asked or no but why you don't use ready oscillator
instead of crystal?
because running high frequency xt is a little bit hard at least at no projects i had success
so, i always use ready oscillators except projects that XT runs by microcontrollers.
i think many members that built your L.R.L also couldn't run XT but they don't know

thank you

[FrancoItaly]

good day

Mr.franco Italy
thank you for sharing project and helping others

don't know if someone asked or no but why you don't use ready oscillator
instead of crystal?
because running high frequency xt is a little bit hard at least at no projects i had success
so, i always use ready oscillators except projects that XT runs by microcontrollers.
i think many members that built your L.R.L also couldn't run XT but they don't know

thank you

You are right, you could also use the "ready oscillators", but I find that the quartz version is the simplest, even most oscillates even without the capacitor between the emitter and the base of the transistor, in the range 2 - 10 Mhz in my opinion is the best choice. The same scheme also works with 20 Mhz, but it is more critical, also because we are at the frequency limit for quartzes that work in fundamental (harmonic). Furthermore it is necessary to have a waveform as distorted as possible, to have many harmonics and a signal of small amplitude in order not to radiate towards the sensor stage.

[ali02]

Hi FrancoItaly
I made your LRL with SMD components, but I don't know how much to tune the potentiometer screws to adjust it? (I'm looking for gold)
But sometimes when I tune the potentiometers, and walk to the refrigerator door, the LED lights up and the speaker beeps, and when I walk away from the refrigerator, the lights go out and the speaker does not beep!
Also, when I walk to the place where the toilet well has been dug, the lights and speakers turn on!
Does this device detect a magnetic field or ions?
Best Regards

[FrancoItaly]

Hi FrancoItaly
I made your LRL with SMD components, but I don't know how much to tune the potentiometer screws to adjust it? (I'm looking for gold)
But sometimes when I tune the potentiometers, and walk to the refrigerator door, the LED lights up and the speaker beeps, and when I walk away from the refrigerator, the lights go out and the speaker does not beep!
Also, when I walk to the place where the toilet well has been dug, the lights and speakers turn on!
Does this device detect a magnetic field or ions?
Best Regards

I don't know (and I don't know if there is) a frequency just for gold. It is normal for there to be many sources of disturbance in the home. Very little is known about the phenomenon, indeed according to "normal" science it does not exist. In my opinion, since it works with an antenna, it is an electromagnetic field.

[FrancoItaly]

I would like to warn those who intend to make the 20Mhz version of my lrl to wait because, while the first one works perfectly, the other two, which I did later, have problems with signal instability. I am making substantial changes and think I have solved the problem. I will post the changes as soon as possible.

[bahrymed]

Good luck mister franco
waiting for your new lrl

[Pahom]

You are right, you could also use the "ready oscillators", but I find that the quartz version is the simplest, even most oscillates even without the capacitor between the emitter and the base of the transistor, in the range 2 - 10 Mhz in my opinion is the best choice. The same scheme also works with 20 Mhz, but it is more critical, also because we are at the frequency limit for quartzes that work in fundamental (harmonic). Furthermore it is necessary to have a waveform as distorted as possible, to have many harmonics and a signal of small amplitude in order not to radiate towards the sensor stage.

Good afternoon Franco! Reading about a new project at 20 MHz, you constantly repeat that the waveform at the output of the generator should be DISTORTED as much as possible. Is this so or is it a translation error?

[FrancoItaly]

Good afternoon Franco! Reading about a new project at 20 MHz, you constantly repeat that the waveform at the output of the generator should be DISTORTED as much as possible. Is this so or is it a translation error?

It is not an error, a distorted signal means that it contains harmonics of higher frequency, in our case: fundamental = 20Mhz, second harmonic = 40Mhz, third = 60Mhz, fourth = 80Mhz, fifth = 100 Mhz, always with decreasing amplitude. The L1 / C10 resonant circuit is tuned to one of these harmonics (I think 80 Mhz or 100 Mhz) and this makes the sensor stage more sensitive.

[Pahom]

It is not an error, a distorted signal means that it contains harmonics of higher frequency, in our case: fundamental = 20Mhz, second harmonic = 40Mhz, third = 60Mhz, fourth = 80Mhz, fifth = 100 Mhz, always with decreasing amplitude. The L1 / C10 resonant circuit is tuned to one of these harmonics (I think 80 Mhz or 100 Mhz) and this makes the sensor stage more sensitive.

Thanks! Another question, in the circuit display 1, the capacitor c1 is indicated 10mf is it an electrolyte? The previous version specified 0.22mF.

[FrancoItaly]

Thanks! Another question, in the circuit display 1, the capacitor c1 is indicated 10mf is it an electrolyte? The previous version specified 0.22mF.

C1 is 10 nF, in the previus version was 22 nF, however it is not very important, however too high values, 100 nF and more, can slow down the response, especially if you search with fast scans.

[Pahom]

C1 is 10 nF, in the previus version was 22 nF, however it is not very important, however too high values, 100 nF and more, can slow down the response, especially if you search with fast scans.

Thanks Franco! It remains to find out to what frequency to tune the input circuit L1 and C1, if I understood you correctly, then it should be approximately in the region of 80-100 MHz

[FrancoItaly]

Thanks Franco! It remains to find out to what frequency to tune the input circuit L1 and C1, if I understood you correctly, then it should be approximately in the region of 80-100 MHz

In the L1 / C10 resonant circuit, by varying the capacitance of the capacitor, we see the amplitude of the signal, at the output of the sensor stage, increase when a harmonic of 20Mhz is reached, and then decrease moving away from it.

[Pahom]

In the L1 / C10 resonant circuit, by varying the capacitance of the capacitor, we see the amplitude of the signal, at the output of the sensor stage, increase when a harmonic of 20Mhz is reached, and then decrease moving away from it.

You say c10 is the one on the TP3 collector

[Pahom]

As I understand it ..... you talked about a circuit with a quartz at 8 MHz, there in the circuit yes L1-C10. I asked you about the 20 MHz quartz circuit and there in the L1-C1 circuit. Thank you Franco, now I understand your explanation about harmonics.