TESORO GOLDEN SABRE

[Max]

Hi Ivconic.
I agree with you but.....
I understand that there is big difference between air and ground.If one detector locate a coin on the air at 40 cm it will detect it at 20... 30 in the ground. But if detect a coin at 20 cm in the air it can't detect it at 25 cm in the ground. This is the point that i say that SS60 is winner. If i will detect with TGS a 25mm coin (2euro) at 30++cm at the air then i will compare it with SS60.
The problem with my TGS is that i can't locate a coin at the distance that you say that you detect. Maybe when i fine tune the Rx coil to detect it at same or near distance. I use a 32cm DDcoil so i must detect it at 30++cm.
Btw do you use an extra capacitor at the Rx coil? (15nf on the board and other cap on the coil)
Regards

Hi Geo,
I've tested my TGS with DD22 and works fine... but not as fine as with bandidoII I've made. I think I've optimized too much DD22 to work on bandidoII at 10Khz to have same depth with TGS.

Also with an OO coil that is very good on BandidoII I get good but not that good results on TGS: it's all about resonance and optimization.

So I've made Ivconic's coils (and other experiments with e.g. OO coils) and found it very good about depth... you need a coil tailored for it... and of course, audio is weak without mod but it's stable and you can ear coin signal at very good depth in air and then in ground too.

Don't use another previous coil with it if wanna see best results. Make using Ivconic's specs and you will see much more depth. Data are really accurate:

TX 100 turns
RX 105 turns
wire = 30AWG (0.25 without varnish)

Look at the picture I've posted some pages ago... look at drawing for nails/wood former and make the same.

Get right inductances and you will be fine with it and TGS... you have to optimize alignment using scope or just watching at detector sensitivity increase.

Best regards,
Max

[Max]

little osc simulations

Hi,
I've downloaded LTspice and using some parts of files from porkluvr I'm doing some training on the simulator... just to see how to move around menus.

I'm happy of results cause I find it really intuitive and easy to use...but that's my impression... you could contestate!

Anyway, I've simulated the original (about) TGS osc with a 4.7 zener diode and 8V supply....

then I've changed the params... using a 15v zener diode (BXZ84C15L) to see the jump at output voltage.

As you can see with that +18v supply and 15v zener it gives about 30Vpp instead of original about 10Vpp: 3 times.

No other mods seem required e.g. for PN2222 that drives the 4024... but , of course, one have to put a stable +18v supply for osc section only (few mA current required)...even 2x9volts batteries could be good for tests.

So maybe people that want experiment with osc signal amplitude can do that way... well signal is not a perfect sinus on sim but I think could be ok for some raw tests.

I think that there's no need of that change on TGS... cause I found really good as is... but if someone would like to try... and inform us of results e.g. in air will be cool!

I can't do cause I have to dismantle the thing from housing and it's now hard work.

Best regards,
Max

[Fred]

Hi
Again some theoric observation : It seem logical that coils shields MUST be isolated where they overlap,or else we are building small loops inside the coil , but i dont see anybody mentioning this.Is everyone isolating his shields?

regards,
Fred.

[Qiaozhi]

I do not agree there. We have different points of view. I already explained that i plan using my coils on quite different machines...I want my coils to be as much versatile as possible. I do not want to "tie up" specific coil to specific detector. Just look Fisher,Garret,Whites,Minelab....you are not pushed to buy exact coil with exact machine. If they have 1000 Spider coils available at shop, you can choose any of them to use with you...let's say CZ5, for example....
I simply refuse to beleive taht they nulled every coil with every machine in producing process..!? White's also; i tested some old coils with brand new machines - working perfect!? How come?
About tuning capacitors; yes, here i agree. You can achieve better performances if coil is fine retuned with it. But this you can do after basic nulling, on some specific machine...
Regards!

I understand what you're saying.
In the case of Fisher, Garrett, Whites, Minelab, however, they undoubtedly have a test setup in their individual factories for nulling coils, so (of course) all the coils they make for their machines will be the same, within certain manufacturing tolerances. Then when they design a new detector, it is designed to use the same coils. This just makes good economic sense. Then by default you can take an old Fisher coil and use it on a CZ5. Why not?

[ivconic]

Hi
Again some theoric observation : It seem logical that coils shields MUST be isolated where they overlap,or else we are building small loops inside the coil , but i dont see anybody mentioning this.Is everyone isolating his shields?

regards,
Fred.

True! But Max and i think Qiuaozhi noted that few times on previous pages....

[ivconic]

I understand what you're saying.
In the case of Fisher, Garrett, Whites, Minelab, however, they undoubtedly have a test setup in their individual factories for nulling coils, so (of course) all the coils they make for their machines will be the same, within certain manufacturing tolerances. Then when they design a new detector, it is designed to use the same coils. This just makes good economic sense. Then by default you can take an old Fisher coil and use it on a CZ5. Why not?

That is what i am trying to build these days! "Testing setup"! Osc.frq. should varry from 6kHz to 20kHz...Sinus and square at output. Adjustable amplitude...On RX side i intend to put high impendance milivoltmeter with 2 outputs; one for VU scale and other for scope....Not ready yet, still collecting infos...

[ivconic]

I have XR2206 on my mind.It is obsolete and rare, but i still have one left in my scrap box...

[Max]

Hi
Again some theoric observation : It seem logical that coils shields MUST be isolated where they overlap,or else we are building small loops inside the coil , but i dont see anybody mentioning this.Is everyone isolating his shields?

regards,
Fred.

Hi,
yes we have explained a number of times I think... shields must be insulated at overlaps and then the only electrical connection is by their wires to gnd...so not in a closed path respect to coils.

If you overlap shields in a conductive way you create shorts around coils... the same if you don't leave the gap in each shield somewhere...

A large closed conductive loop will develop as much eddy currents that you'll easy saturate RX stage that way... and even if not totally saturated the RX stage of course this will destroy your SNR.

You need gaps and you need intershielding insulation: paper or some plastic tape is good at that overlaps.

Best regards,
Max

[Fred]

Hi Ivconic,
Here XR2206 is still available (somewhat expensive),so if you need more and i can help you let me know.Same for LF353 :www leiritronica.com (its in portugal)
regards,
Fred.

[Max]

FOR GEO

Hi Geo,
I re-tested it with 2eur on the fly... and in air I get about 37cm at max depth.

When I put coin moving in the 35cm range the sound is not weak like at 37cm and you can ear it good on headphones.

Don't know about in the ground for 2eur but it must be something more than 1eur detection also in that case (metals are about the same even if disposition is reversed).

I think that TGS would detect 2eur coin at least at 32cm in the ground with 10'' coil... or more depending on soil.

Best regards,
Max

PS : about audio speaker you can use 8ohm but I prefer 16ohm for that, sound is louder.

[ivconic]

Thanks Fred.
I just installed LTSpice on my pc...Trying to input schematic...Damn! I am still new in this! How to rotate component? I cant fin in help....
Need urgent help!
How to rotate damn component?
Max can you upload your file for LTSpice here?

[Max]

Thanks Fred.
I just installed LTSpice on my pc...Trying to input schematic...Damn! I am still new in this! How to rotate component? I cant fin in help....
Need urgent help!
How to rotate damn component?
Max can you upload your file for LTSpice here?

Hi,
to rotate use CTRL-R.

The osc files ? Yes , of course.

Here it is.

Kind regards,
Max

[ivconic]

Thank you very much! At the same moment i founded it.....Is there any explanattion of more shortcuts? Hot to flip component etc.... I am in the heat of this now....!

[Max]

Thank you very much! At the same moment i founded it.....Is there any explanattion of more shortcuts? Hot to flip component etc.... I am in the heat of this now....!

Hi,
yes there are...

mapping is here:

tools->controlpanel->drafting_options->hot-keys

Just follow menus and panes... you can also customize some stuff.

Best regards,
Max

[ivconic]

Last time i used something similar was back in 1992. !!! It was some EWorkbench under win 3.11.... I still cant give off habits working with it...
Now....i opened yor file and it is ok.
If i want to se scope, what should i do?
I clicked on "Pick visible traces" and can choose between them. So i click on V(phi) to see output scope...It is showing something??? High density scope...Damn! I am to laic for this! How can i adjust scope to see nice sinus as on your posted photo?
Sorry cose i bug you here....few hints more and i'll shut up...
Thanks again!