thank you very much sir franco

Nice PCB design. I like your idea to apply some sort of Manhattan-style board construction.

Good Work
 

:lol:

I experiment with ferrite 20 c.m antenna coil, the signals inside the house the best I caught but nothing out goals, like a piece 5 c.m the tag coil, centering best, but cuts the distance.
I'm still in the experiments.


https://postimg.org/image/n1bfs1fon/

https://postimg.org/image/lqvh3bt17/

Who can tell us, the machine will react on metals? Why use 8 m crystals? If for 20 m crystals, can it work? thank you

Hi liudengyuand,

Lrls react on long buried non ferrous metals, better on gold and silver but with too much gain react also to "compass effect", ie it has a signal when the LRL is aligned with the north / south. My lrl works in the range 2.5Mhz - 10Mhz and it is not necessary to change.
The oscillator provides a carrier that is somehow modulated by the "phenomenon", perhaps even works with 20MHz changing but some component, but then again it's not important


Best Regards

OK
 

thank you

Hello, francoltaly,thank you for sharing this project, I made it, as there is no suitable element, all I use bc547 triode, c1 with no 390 pf, I use 470 pf, its capacity is large, whether to have impact on circuit? I have a dc voltage measurement ic1 3 feet, 6.08 v, the voltage is normal? It is not sensitive to electric spark, I use mobile phone call, it can detect 80 cm interference signal, then how can we know its sensitivity is the best? Please reply, thank you very much

Hi liudengyuand,

with "dc voltage measurement ic1 3 feet, 6.08 v" do you mean the 7412 IC output? In this case there is an error, with 18V (input from the battery), the output (of course) has to be 12V. All transistors of the type BC ... C are suitable. As for C1 the original value in the diagram is 330pF but other higher values are fine if the oscillator is stable, I recommend a lower value and maybe increase it. As I mentioned earlier the only test needed is to touch the antenna and check whether the output voltage decreases (even a few mV). All the other tests do not help much.

Best Regards

Hello! Yes I measured voltage c18 is 6.08 v, I no problem of supply voltage of 11.25 v, for electric spark, it is how far distance should be sensitive? And the use of capacitance, whether to need to use the capacitance with black points? The 6.08 v is normal, please?

All the values of the components are calculated for a stabilized voltage of 12V, therefore it is preferable to use 2 9V batteries connected in series (for a total of 18V), not recommend other solutions, otherwise it is necessary to recalculate many values. I think that any kind of capacity you can use and as for the tests is as good as I said in the previous post.

Would you please tell me specifically c18 volts dc voltage value should be in? thank you

It's good in the range 4 -6V

Because I can't watch video files on youtubu, I would like to request you to send a copy of your machine test video to me, mp4 format, my email dds118@foxmail.com, thank you

I have no video by myself, tomorrow I try to send you a youtube video by other members of the forum.

Hello! Due to network problems, I can't watch youtube video, I can only watch mp4, if who can give me email mp4, I thank you very much?

Yes tomorrow I will do, now I have no more time.

Tell me the members that mounted on which objects the lrl is sensitive, when touching fingers antenna does not detect, only with metal leaning on the antenna lrl whistle

Why I do circuit antenna with fingerprint, it did not respond? Only when talking on the phone near the l1. It didn't have a reaction, low sensitivity, how to get to the induction of metal that weak signal?

You have followed the procedures that I mentioned?

Hi liudengyuand,

I can not send the email, I received this email:
"The remote mail system said: 550 Mail content denied. http://service.mail.qq.com/cgi-bin/help?subtype=1&&id=20022&&no=1000726"

Best Regards

Hello, please send to l2497003283@sina.cn, thank you

Ok

Sorry but also this Email address is not working.

l2497003283@sina.cn is correct, I can receive the other email, your email problem?