Lrl from Italy

[FrancoItaly]

Originally Posted by edward

i tested 100 pf the voltage is about 1 volts when i put 20 pf for c13 and c14 the output is 0 volt but there is another problem when i connect the quartz the output is 0.6 volts

You have to increase the total value of C2 / C3 / C4, ie put only C2 = 1pF, if not enough it increases to 2pF until the output voltage is in the range 3 - 6V (non-critical).
Remember that with two or three capacitors in series the total capacity is less.

[erfan]

Hello every body
And hello dear franco italy
And a special thanks to franco italy.
Because he shared what ever he knows with no financial out look.I wish best for franco italy.

[FrancoItaly]

Originally Posted by erfan

Hello every body
And hello dear franco italy
And a special thanks to franco italy.
Because he shared what ever he knows with no financial out look.I wish best for franco italy.

Thanks for the compliments, there can be real progress only with the collaboration of everyone. The "phenomenon" that allows the operation of the lrls is still largely unknown, but it is as real as many members have already been able to verify. As far as possible I help everyone in the realization of my lrl and take this opportunity to summarize the useful advice for the construction:
- the sensor stage has a very high gain and therefore there is the risk of self oscillations, it is advisable to use a double-sided pcb with the lower face connected to the negative and on the upper one the components will be soldered, no holes are necessary , only that, if necessary, to connect the upper mass to the screen constituted by the lower face of the pcb.
- the transistors are of the BC183C type or equivalent (for example BC549C or others), also the BC183B can be used as long as the beta (gain) is higher than 500.
- the total value of C2 / C3 / C4 establishes how much the quartz oscillator signal will be amplified by the sensor stage and therefore
determines the output value.
- C13 / C14 determine the gain of the sensor stage, in fact, increasing the value of C13 / C14 lowers the actual value of R10 / R12 (for the frequency of 8Mhz) and therefore increases the gain of the stage.
- On the TR2 base there is the mixing between the 8Mhz signal and the "phenomenon" captured by the stylus antenna.

[edward]

Originally Posted by FrancoItaly

Thanks for the compliments, there can be real progress only with the collaboration of everyone. The "phenomenon" that allows the operation of the lrls is still largely unknown, but it is as real as many members have already been able to verify. As far as possible I help everyone in the realization of my lrl and take this opportunity to summarize the useful advice for the construction:
- the sensor stage has a very high gain and therefore there is the risk of self oscillations, it is advisable to use a double-sided pcb with the lower face connected to the negative and on the upper one the components will be soldered, no holes are necessary , only that, if necessary, to connect the upper mass to the screen constituted by the lower face of the pcb.
- the transistors are of the BC183C type or equivalent (for example BC549C or others), also the BC183B can be used as long as the beta (gain) is higher than 500.
- the total value of C2 / C3 / C4 establishes how much the quartz oscillator signal will be amplified by the sensor stage and therefore
determines the output value.
- C13 / C14 determine the gain of the sensor stage, in fact, increasing the value of C13 / C14 lowers the actual value of R10 / R12 (for the frequency of 8Mhz) and therefore increases the gain of the stage.
- On the TR2 base there is the mixing between the 8Mhz signal and the "phenomenon" captured by the stylus antenna.

Hi mr franco and thank you for your help

I tested bc548, bc547 b , bc 238b , bc 547c , and the results was same, my pcb is self oscillation, i have to use 20 pf capacitors for c13 , c14 to avoid from self oscilation
I think when i increase total value of c2 , c3 , c4 for increasing output voltage the lrl sensivity decreases

Now i have 2 question mr franco
1- how much is maximum amount that can be used for r10 and r12
2- does your lrl dont work with low voltage in output? ( for example 0.5 volts or 0.6 volts)

[FrancoItaly]

Originally Posted by edward

Hi mr franco and thank you for your help

I tested bc548, bc547 b , bc 238b , bc 547c , and the results was same, my pcb is self oscillation, i have to use 20 pf capacitors for c13 , c14 to avoid from self oscilation
I think when i increase total value of c2 , c3 , c4 for increasing output voltage the lrl sensivity decreases

Now i have 2 question mr franco
1- how much is maximum amount that can be used for r10 and r12
2- does your lrl dont work with low voltage in output? ( for example 0.5 volts or 0.6 volts)

1 -Usually it is chosen for R10 / R12 a value lower than that of R9 / R13. I made several copies of my lrl and I always managed to eliminate self oscillation. Try to remove C13 / C14, in this way it should stop oscillating, if so, decrease R10 / R12 until it oscillates again, then increase again R10 / R12 until the oscillations cease. For example R10 / R12 = 1 K no oscillations, R10 / R12 = 680 ohms no oscillations ... R10 / R12 = 220 ohms no oscillations, R10 / R12 = 100 ohms yes oscillations, choose R10 / R12 = 220 ohms. This difficulty in eliminating self oscillations makes me think of a defect in the pcb, there may be some parasitic coupling. I always recommend using a double-sided pcb.
2 - my lrl works also with low voltage output but for me it's better at least 2V, in fact it could happen when the installation was completed or in the field that the tension lowered further, in this way it would also greatly reduce the sensitivity, since it could not regulate the threshold effectively.

[edward]

Originally Posted by edward

Hi mr franco and thank you for your help

I tested bc548, bc547 b , bc 238b , bc 547c , and the results was same, my pcb is self oscillation, i have to use 20 pf capacitors for c13 , c14 to avoid from self oscilation
I think when i increase total value of c2 , c3 , c4 for increasing output voltage the lrl sensivity decreases


Now i have 2 question mr franco
1- how much is maximum amount that can be used for r10 and r12
2- does your lrl dont work with low voltage in output? ( for example 0.5 volts or 0.6 volts)

Hi mr franco

There is something interesting

When i use switching power supply the output voltage increases from 3 volts to 6 volts( without quartz)
I think this is because of long wire of switching power supply
The last test was with 2× 9 volts battery
I think self ocsilating has another reason
Before that i made your lrl sensor with your pcb layout and the results was same i had 3 volts in output without quartz
Both pcb was double side
What about the tr4 collector? how much should this voltage be?

[edward]

Originally Posted by FrancoItaly

1 -Usually it is chosen for R10 / R12 a value lower than that of R9 / R13. I made several copies of my lrl and I always managed to eliminate self oscillation. Try to remove C13 / C14, in this way it should stop oscillating, if so, decrease R10 / R12 until it oscillates again, then increase again R10 / R12 until the oscillations cease. For example R10 / R12 = 1 K no oscillations, R10 / R12 = 680 ohms no oscillations ... R10 / R12 = 220 ohms no oscillations, R10 / R12 = 100 ohms yes oscillations, choose R10 / R12 = 220 ohms. This difficulty in eliminating self oscillations makes me think of a defect in the pcb, there may be some parasitic coupling. I always recommend using a double-sided pcb.
2 - my lrl works also with low voltage output but for me it's better at least 2V, in fact it could happen when the installation was completed or in the field that the tension lowered further, in this way it would also greatly reduce the sensitivity, since it could not regulate the threshold effectively.

I removed c13 , c14 and i had 6 volts in output without quartz
R10 , R12 was 1 k resistors i chenged these with 2× 5k potentiometers and i started to increasing the potentiometers in 4k for both output voltage were 0 volt

I have 8 volts in tr4 collector

[FrancoItaly]

Originally Posted by edward

I removed c13 , c14 and i had 6 volts in output without quartz
R10 , R12 was 1 k resistors i chenged these with 2× 5k potentiometers and i started to increasing the potentiometers in 4k for both output voltage were 0 volt

I have 8 volts in tr4 collector

Well, 6V in output it's ok. The only unknown is if the gain is sufficient, however the further gain of the antenna amplifier should compensate.

[edward]

Originally Posted by FrancoItaly

1 -Usually it is chosen for R10 / R12 a value lower than that of R9 / R13. I made several copies of my lrl and I always managed to eliminate self oscillation. Try to remove C13 / C14, in this way it should stop oscillating, if so, decrease R10 / R12 until it oscillates again, then increase again R10 / R12 until the oscillations cease. For example R10 / R12 = 1 K no oscillations, R10 / R12 = 680 ohms no oscillations ... R10 / R12 = 220 ohms no oscillations, R10 / R12 = 100 ohms yes oscillations, choose R10 / R12 = 220 ohms. This difficulty in eliminating self oscillations makes me think of a defect in the pcb, there may be some parasitic coupling. I always recommend using a double-sided pcb.
2 - my lrl works also with low voltage output but for me it's better at least 2V, in fact it could happen when the installation was completed or in the field that the tension lowered further, in this way it would also greatly reduce the sensitivity, since it could not regulate the threshold effectively.

I conected the quartz and out put voltage is 0 volt

C13 , c14 removed
R10 , r12 4 kilo ohm
Quartz connected output voltage is 0 volt
Quartz disconnected out put voltage is 0 volt
Tr1 emitter frequency is 8 mega heartz
Tr4 collector voltage is 8 volt

And I am tired

[FrancoItaly]

Originally Posted by edward

Hi mr franco

There is something interesting

When i use a the output voltage increases from 3 volts to 6 volts( without quartz)
I think this is because of long wire of switching power supply
The last test was with 2× 9 volts battery
I think self ocsilating has another reason
Before that i made your lrl sensor with your pcb layout and the results was same i had 3 volts in output without quartz
Both pcb was double side
What about the tr4 collector? how much should this voltage be?

switching power supply is not recommended. May be in the laboratory there are other forms of disturbance, you have to try outside with battery power. It is not possible to measure the signal on the collector of TR4 with an oscilloscope because the signal disappears, the DC output measurement is sufficient. Also try to keep the antenna very short, 10 -15cm, inside the laboratory.

[FrancoItaly]

Originally Posted by edward

I conected the quartz and out put voltage is 0 volt

C13 , c14 removed
R10 , r12 4 kilo ohm
Quartz connected output voltage is 0 volt
Quartz disconnected out put voltage is 0 volt
Tr1 emitter frequency is 8 mega heartz
Tr4 collector voltage is 8 volt

And I am tired

DC voltage of TR4 collector must be about 5-6V but with R10=1K, by changing R10 also collector voltage changes. You have =0V with quartz because the gain is very poor, try C2 only (disconnect C3/C4) you have 1pF, if you have no result try 2pf or more.

[edward]

Originally Posted by FrancoItaly

switching power supply is not recommended. May be in the laboratory there are other forms of disturbance, you have to try outside with battery power. It is not possible to measure the signal on the collector of TR4 with an oscilloscope because the signal disappears, the DC output measurement is sufficient. Also try to keep the antenna very short, 10 -15cm, inside the laboratory.

Yes mr franco i was thinking this is for laboratory i think the test should be outside the laboratory

[FrancoItaly]

Originally Posted by edward

Yes mr franco i was thinking this is for laboratory i think the test should be outside the laboratory

When I said that the measurement could not be performed with the scope I meant the 8MHz signal. Tell me the measurements of your sensor stage pcb, have you connected the lower part to the ground?

[edward]

Originally Posted by FrancoItaly

When I said that the measurement could not be performed with the scope I meant the 8MHz signal. Tell me the measurements of your sensor stage pcb, have you connected the lower part to the ground?

Yes the lower part was connected to ground

[edward]

Originally Posted by FrancoItaly

DC voltage of TR4 collector must be about 5-6V but with R10=1K, by changing R10 also collector voltage changes. You have =0V with quartz because the gain is very poor, try C2 only (disconnect C3/C4) you have 1pF, if you have no result try 2pf or more.

But if the laboratory is the reason this means when the lrl approaches the phenomenon the sensor start to self oscilating??

[FrancoItaly]

Originally Posted by edward

But if the laboratory is the reason this means when the lrl approaches the phenomenon the sensor start to self oscilating??

No, the lrl is also very sensible to many electromagnetic disturbances, also in my lab I have many signals.

[edward]

Originally Posted by FrancoItaly

No, the lrl is also very sensible to many electromagnetic disturbances, also in my lab I have many signals.

In my laboratory there is laptop , wireless modem , swithching powersupply , osciloscope , near the pcb when i am testing and on the left and right sides of my laboratory there is tow stores with same instruments

[FrancoItaly]

Originally Posted by edward

In my laboratory there is laptop , wireless modem , swithching powersupply , osciloscope , near the pcb when i am testing and on the left and right sides of my laboratory there is tow stores with same instruments

sources of disturbance can be even a few meters away. Several years ago I was in an area with TV repeaters, in that place the lrl was practically unusable for a radius of at least 100m. The input circuit, L1 / C10, is tuned around 100Mhz, any transmitter on that frequency, or superior harmonic or sub harmonic, can generate a signal in the lrl.

[edward]

Originally Posted by FrancoItaly

sources of disturbance can be even a few meters away. Several years ago I was in an area with TV repeaters, in that place the lrl was practically unusable for a radius of at least 100m. The input circuit, L1 / C10, is tuned around 100Mhz, any transmitter on that frequency, or superior harmonic or sub harmonic, can generate a signal in the lrl.

I tested the circuit in another place and the results was same

I have 7 volts in my output without quartz and c13 , c14 560pf
C2 , c3 , c4 = 1 pf r10 , r12 =1k
Does your lrl work with this state and without quartz? I have 6 to 7 volts in my aoutput and when i touch the antenna the voltage decreases about 200 milivolts

[FrancoItaly]

Originally Posted by edward

I tested the circuit in another place and the results was same

I have 7 volts in my output without quartz and c13 , c14 560pf
C2 , c3 , c4 = 1 pf r10 , r12 =1k
Does your lrl work with this state and without quartz? I have 6 to 7 volts in my aoutput and when i touch the antenna the voltage decreases about 200 milivolts

Yes, my lrl also works this way, in fact this lrl originated from an RF sniffer that self oscillated, later I wanted to create a lrl simpler to set up. I realized that the self-oscillation was due to the characteristics of the pcb.

[edward]

Originally Posted by edward

I tested the circuit in another place and the results was same

I have 7 volts in my output without quartz and c13 , c14 560pf
C2 , c3 , c4 = 1 pf r10 , r12 =1k
Does your lrl work with this state and without quartz? I have 6 to 7 volts in my aoutput and when i touch the antenna the voltage decreases about 200 milivolts

What do you think that i build your first schematic( self oscilation)? Which schematic is better?

[FrancoItaly]

Originally Posted by edward

What do you think that i build your first schematic( self oscilation)? Which schematic is better?

If the signal at the output is stable, there is no difference.

[edward]

Originally Posted by FrancoItaly

Yes, my lrl also works this way, in fact this lrl originated from an RF sniffer that self oscillated, later I wanted to create a lrl simpler to set up. I realized that the self-oscillation was due to the characteristics of the pcb.

I will complete this pcb and will go to test point
I have a test point with 2 grams gold at 10 cm depth buried 3 years ago and a 15 cm copper bowl buried 5 years ago at 60 cm depht

[edward]

Originally Posted by FrancoItaly

If the signal at the output is stable, there is no difference.

Output voltage is stabe at 6.6 volt and when i touch the antenna the voltage decreases 200 milivolts

[FrancoItaly]

Originally Posted by edward

Output voltage is stabe at 6.6 volt and when i touch the antenna the voltage decreases 200 milivolts

Well, it's ok.