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So i guess "Post Quick Reply" is all what i can do here.
Here is what i wanted to pointed out Gurdal;
watch this draw and you will understand.
A type is much easier to balance than B type.
Unfortunately you made B type coil.

[ATTACH]54090[/ATTACH]

Yes, yes, I agree. A type is much better than the B type. The range of side to side movement for A type is larger per millivolt up or down. Which means that you don't fall off a cliff with the slightest shift, as is the case with type B. Translation, easier to set up.
In type B, the null occupies a very narrow corridor, with a steep fall off to either side, moreso than type A

[ivconic]

So i guess "Post Quick Reply" is all what i can do here.
Here is what i wanted to pointed out Gurdal;
watch this draw and you will understand.
A type is much easier to balance than B type.
Unfortunately you made B type coil.

[ivconic]

I am not allowed to use "Go Advanced" reply on this topic.
Admins watch this and give me explanation:

[ivconic]

Now what?

[ivconic]

Gurdal we can continue via emails from now on.
I am too tired to annoy myself with this forum bugs and issues anymore.
Send me email and we will continue talking there.
Cheers!

[ivconic]

For weeks i have problems to easy reply here on this topic only!??
It's like somebody put some obstacle purposely to this topic... is it?
When i click on "reply" and "go advanced"; i get this kind of screen:



Not allowing me to write anything nor to post reply.
Unlike the other topics where i can reply easy with no such problems.

[gurdal]

Hi master;
metal searching in the woods.
for small or large metals
best tx and rx frequency.

sample tx 7.5 kHz,
rx how many khz should be.
disc in closed state
Regardless of ground switch location
Is the ferrite core erased.
I have to understand the ground balance setting.
I will be glad if you share a short article.
Best regards
Gurdal

[ivconic]

I am glad you made it!
Bravo!
Make sure that metal part of potentiometers is having good contact with pcb.
If needed; you can solder piece of bare wire on potentiometer housing and connect additionally to pcb minus plane.
Occasional chatters and sensitivity to moving and turning the pcb is due high gain in channels and probably the coil is not matched best it could be.
Lower the Sensitivity to "90%" or rise the 180 ohms resistor to 200-220 ohms too.
I am sure you will adapt the coil too.
You did very good job!
Excellent!

[gurdal]

hello ivica my master;
First of all, thank you very much for your time.
no problem with smd drawing.
short circuit caused by me.
I will adjust and fine tune the Tx and rx frequency values.
thank you so much

[gurdal]

Hi ivica master;
I think I found a mistake.
I did wrong somewhere.
I'm carrying the big pieces to the other side.
I'll write when I test.
Best regards
Gurdal

[ivconic]

Thanks master;
I added 1 m instead of 1.3 m.
There was no 3.9nf I used 1nf.
Could the problem be the quality of the parts.
It's interfering like there's a place that doesn't take a chassis.

FU..ING forum engine is lagging again, i am having terrible problems to reply to your answers now...
Something very bad is going on with this forum for quite some time.
...
I'll try to post this post.
1M instead 1M3 is not a problem, you only lowered gain (which is even worse now to have so much noise with lower gain).
1nF instead 3n9 is PROBLEM. Phase is displaced ... God knows how many degrees from the needed angle.
You should put at least 3n3 instead 1nF. 1nF is WRONG.
You can put 1n5 and 2n2 in parallel.

[ivconic]

You did few things on pcb unlike i expected and planned, when i drawn it.
You put through hole components on the same side as SMD components.
Also you put potentiometers backwards.
And what's even worse; you used plastic cased potentiometers and now those are acting like "antennas".
Reason for 4 holes on pcb, for potentiometers; connected to minus (minus is "ground" here, although there is virtual ground too, generated by LM358, to split power supply by 2)...
so reason i drawn wide copper areas around holes for potentiometers is to use metal case potentiometers (put through holes from opposite side than what you do) and to screw them hard and to "minus" (ground) their cases good.
If you used metal case pots; the cases would also act as "ground" and "cage" for signal paths.
Also. like i said (and explained much earlier); "yellow" components should be put from the opposite side of the pcb than SMD components.
All except 7809.
Because main traces for those components are done on top layer, easier to solder them on pcb without metalized vias.
Now you have problem there. There is obvious break in some ground path and now is much harder to trace it out.
I will repeat; when i say "ground" i mean minus. Battery minus. It is "ground" in particular case. For "grounding".
And also there is virtual ground, generated with LM358, but not used for "grounding".
Please don't mix those two.
So, hums, self oscillations and noise on pcb; most probably came from some broken path, missing solder (via maybe) and above all amplified by plastic potentiometer cases and through hole components put on wrong side.
If you list back this topic; i am sure you will find out my post where i was specific about mounting components. I already explained that earlier.
...
But it is alright, don't worry. Those are usual mistakes when you do some thing for the first time. Normal.
Even today 32 years later with experience; i make similar mistakes from time to time.
...
What would i do on your place? Hmmmm...
I would try to find broken path by tracing signal paths from frontends to last stages, using osciloscope.
Also i would misplace all the through hole components and put them on bottom layer (from behind from position on your video).
Also i would pull out all those 4 plastic potentiometers, use new ones in metal cases, mount them opposite from the side you mounted and screw them hard with the srews.
Before screwing; i would put solder on those pot holes, wide layer of solder, so to make best possible connection with pot cases and srews.
Solder those holes wide and from both sides.
At the end; all the SMD components will stay the same as they are now, on top layer, along with 7809, but all other components, connection pins and connectors, would be displaced to bottom side, unlike the case you have now.
That's how you will have clear and clean approach to all the traces and paths from the top side. And there will be no 4 "anntennas" (plastic pots) to "irradiate" from the top layer.

[gurdal]

Thanks master;
I added 1 m instead of 1.3 m.
There was no 3.9nf I used 1nf.
Could the problem be the quality of the parts.
It's interfering like there's a place that doesn't take a chassis.

[ivconic]

Hi master;
I measured the supply voltages.
I did not take any other action.
I will act according to the answer from you.
I am aware you are angry but sorry.

No, of course i am not angry, why should i be?
Only don't like to repeat same question many times.
And it is vital to know are the voltages alright.
Looking your draw and video; i see no problem with voltages.
Everything seems fine with power supply.
But also i see and hear lot of noise on pcb, self oscillations and sensitivity to your presence and touching some parts.
Looks like some ground is missing there... but how to find it?
Something is terribly "ringing" and oscillating on pcb.

[gurdal]

Hi master;
I measured the supply voltages.
I did not take any other action.
I will act according to the answer from you.
I am aware you are angry but sorry.