expert parameter, I need your diagram , don't stop searching :)

Until now i did n't find full schematic...:angry:
The only that i found is the frequency selector.
Varicaps have capacitance between 20 and 500pF (if i remember ok).

thank you very much, we are missing only the receiver circuit and meter :)

Here is what i found from true rms meter.
There is n't schematic for receiver but it is the same as prototype with the difference of ic's.
I don't remember other changes...

thank you, I will try to find time for its realization :) I want to know does your gold gun have a good reception from VLF stations ?

Yes... always it receives at least one VLF station with signal more than 200mv.
As i saw at original GG when signal was lower than 150mv it was noise so no ability to detect any object.
Also is indicated only for big targets...

does it receive when the antenna is pointed towards the transmitter or in width or in both cases ?

I don't know who is the transmitter that it receives, i only look the meter for high signal and a narrow zero.

thanks, what is the length of each ferrite rod , wire diameter , number of turns ?

I use only one ferrite 20cm.
Inductance is near to 10mH per section.
Wire 0.2mm diameter
Turns... i don't remember:frown:

what's te distance between the two windings ? and the total inductance ?

I don't remember. Ferrite is closed in a plastic tube...
Total inductance must be more than 30mH..

Thank you :)

Today i measured the frequency of each band using this selsctor.
so i have

1. 24.6 .... 30.5 Khz
2. 17.8..... 25.5
3. 14.5.....19.7
4. 11..... 12.9
5. 9.7 ......10.9
6. 6.3 ......6.6 Khz

As you see it receives directly from 6 ... 33 Khz (-10db).
So with a good scan will find a strong vlf station inside one of all these bands.

:)

very good method :) I need to know the position of the two potentiometers (tune and volume) thank you :)

What do you mean????

where i connect these two pots ( tune and volume ) in the diagram ?

excuse me the tune pot is for the varicap
it remains that the pot volume which is not on the diagram

You must connect the other half of TLC272 to pin 8 of TL071 via 100n. Draw the same schematic with the other half and connect a potentiometer at output (pin1). Audio ampl must be at different box and far from lrl. GG is very sensitive to self-oscillations. Usyally i don't use the audio, only the meter.

Thank you :)

What do you think for this point?

https://youtu.be/ioXUAYkFxRM

Question to all who are in the subject. I understand correctly that there are two circuits, one on the TL084 is an earlier circuit and the second circuit is on the LM324.

LM324 and TL074 are similar ICs. No differences for this simple circuit...
Both are quad op amplifiers.

:)

Too noisy without a signal to the station. I'll try to bypass the remaining two unused channels.

And I found why it was making noise, fixed it. Cool receiver.