Lrl from Italy

[FrancoItaly]

Did you use any other antenna, copper etc. as metal type?

I use stylus antenna and some time ago the coil antenna but without finding differences, you could try to change the number of turns.

[brain]

I use stylus antenna and some time ago the coil antenna but without finding differences, you could try to change the number of turns.

I know this, my purpose I think that the metal used in the antenna has an effect on the phenomenon.

[brain]

I use stylus antenna and some time ago the coil antenna but without finding differences, you could try to change the number of turns.

I know this, my purpose I think that the metal used in the antenna has an effect on the phenomenon.
I made a copper antenna, I will try it at the test site on Sunday

[liudengyuand]

good

[mustefa ubram]

hi franco

I'm back after a long time
I have a question
Why didn't you use high gain ICs in the design for the amplifier part ca3130 or ca3140 or....?

Do you think it is possible to replace the IC with a transistor?

[FrancoItaly]

hi franco

I'm back after a long time
I have a question
Why didn't you use high gain ICs in the design for the amplifier part ca3130 or ca3140 or....?

Do you think it is possible to replace the IC with a transistor?

It is not possible to replace a transistor with a normal IC which are basically only for audio frequency due to the too low gain over the Mhz. The CA3130 reaches 15 Mhz but with a gain of one, if you make a 100 Khz RC oscillator with a LM358 you will see that you do not get a square wave (which contains many harmonics over 100 Mhz). Better is the TL081 which at 100 Khz gives an acceptable waveform.

[mustefa ubram]

It is not possible to replace a transistor with a normal IC which are basically only for audio frequency due to the too low gain over the Mhz. The CA3130 reaches 15 Mhz but with a gain of one, if you make a 100 Khz RC oscillator with a LM358 you will see that you do not get a square wave (which contains many harmonics over 100 Mhz). Better is the TL081 which at 100 Khz gives an acceptable waveform.

I gave an example ca3130 or ...

So the problem here is bandwidth?If there is, can IC be replaced with 100 MHz bandwidth?

I mean only for the amplifier and mixer parts Not the oscillator part

[mustefa ubram]

Please give a general description of how the device works from zero to 100?

And important factors in metal detection

[FrancoItaly]

Please give a general description of how the device works from zero to 100?

And important factors in metal detection

The sensor stage amplifies a signal of 8 Mhz and this with a gain of about 500 X 500 X 500 times, in fact each BC ... C transistor has a beta of 500, this in theory and without counting the losses, but the fact remains that a 100Mhz bandwidth IC amplifies 100Mhz / 8Mhz = about 12 times.

[liudengyuand]

The largest depth of 2m

[brain]

In the northern latitudes of the U.S. the total magnetic field strength is in the order of 50,000 to 55,000 nanoTesla and varies from location to location. Short period variations due to magnetic storms may reach several hundred nanoTesla. Diurnal variations caused by solar induced ionospheric currents are in the order of tens of nanoTesla. Presently, the long term trend of the total field is in the order of minus 90 nanoTesla per year ( steadily decreasing).
The proton precession frequency detected by a suitable sensor in the geomagnetic field of the earth will be at a frequency in the audio range:
Example: 42.58 mHz / Tesla x 52500 x 1E-9 Tesla= 2235 Hz
In my northeast location the frequency readings average about 2275 Hz, corresponding to a total field of about 53,400 nanoTesla. This seems to correlate with published models. This figure also agrees with the value obtained using the fluxgate magnetometer that was calibrated using a Helmholtz coil. The fluxgate sensor was tipped upward from a horizontal position to nearly vertical to obtain the maximum reading of the earth field.

[mustefa ubram]

hi franco

How does this circuit react to the cavity? Does the cavity reduce the output voltage?

[FrancoItaly]

hi franco

How does this circuit react to the cavity? Does the cavity reduce the output voltage?

I don't know, I have not experiences.

[mustefa ubram]

your pcb

[FrancoItaly]

I gave an example ca3130 or ...

So the problem here is bandwidth?If there is, can IC be replaced with 100 MHz bandwidth?

I mean only for the amplifier and mixer parts Not the oscillator part

The problem is the gain, in my opinion another solution is not possible, furthermore I do not understand why to change a functioning and economic solution with something that is certainly more expensive, assuming that it exists with the necessary characteristics.