Selectivity with LM567

[Pahom]

Originally Posted by omar

Hello Bahoum....

It seems that it is very difficult for amateurs and even advanced people. Dealing with radio frequencies and radio resonance circuits, adjusting, stabilizing and powering them, is not easy. The capacitive change, if any, will be slight, and sorting it out from all this noise seems impossible. I don't know, there may be a simpler solution.
What do you think? Give us an idea or theory .

I don't know! There seems to be a theory that the useful signal of the phenomenon is in the noise. By amplifying the signal, the noise is also amplified. It is necessary to somehow isolate the necessary signal without losses. In the Mineiro and PD Alonso circuits there is a passive filter, perhaps this is a ready-made solution.

[omar]

We will try to get out of the vicious circle. And find a new effective and feasible detection technique. It may be simpler than we expect. If what we are looking for is an electrical signal, it has no frequency (but it has a pulse. The number of pulses per second is the frequency of the signal in hertz). These pulses are very sharp, not like radio frequencies, they are not sine or square, but like the teeth of a comb. They may not appear on an oscilloscope. When you look at them, you think they are high frequencies in gigahertz ( modified ). This is a similarity.
And God knows best about His creation.

There is a point to be made that may seem reckless...the signal directly on the ground is 20 times stronger or more than it is in the open air.


An illustrative image of the signal shape.