TESORO GOLDEN SABRE

[simonbaker]

Simonbaker,
Can you make some conclusions?
No matter what I try so far this last TGSL just refuse to work like it should.
Now after so many coils I am shore that coil is problem that can't solve so far.
I use 0,25 bare wire.0,27 with varnish.

Old DD27 that were made for previous TGSL device.:
C12 .096
C15 .161
TX 6,21mH 27,9
RX 6,77mH 29,1
13kHz
nulled to .050

OO coil
C12 -.073
C15 -.325 Why both -
13,7kHz
TX 6.00 26,6
RX 6,58 27,6
nulled to .200

Both coils shielded.And sealed with epoxy.But I still have this poor performance.Low sens.1 euro coin at 22-23cm.
RX cap is 15N.Now I put 100k pot for.GEB.

My last /still not shielded and sealed coil/isD27
TX 5,93mH 26,7
RX 6,58mH 28,0
13,9 kHz
C12 .209
C15 -1.185


I now that I miss something and just looking for solution.Because I like this project.

(I moved answer to different thread because too confusing here for people building standard TGSL.)

http://www.geotech1.com/forums/showpost.php?p=95030&postcount=26

-SB

[Max]

Dear All
why doesnt TGSL reject gun bullet?

kind regrads

Hi,
which kind ?

Lead made , old style ? Already answered by Ivconic....

Some are made of different stuff...

also depleted uranium!

Beware of those... are HOT stuff...

I know people (childrens mostly) in your country found them in the streets after A10 raids... and tank perforating ammunitions used... and PLAY WITH THEM...NO GOOD.

People beware of those!

Same apply to Serbia and other countries.... that share same "luck" after NATO raids!

Now about all balcans are scattered by these things in soil... NO GOOD.

Ivconic surely knows... as well other people, thunters there.

IT'S REAL, REAL AND HEAVY DANGER.

But maybe you mean AK47 stuff... ammunitions and some western made too... some are lead with copper jacket + nickel etc... full-metal-jacket things uses also some kind of steel.

The fact MDs detect bullets is usually a PLUS... of course, as with any thing, depends on scenario... if have all search field full of them it's really annoying stuff... and also potentially dangerous if some are radioactive too!

Kind regards,
Max

[ivconic]

Dear All
why doesnt TGSL reject gun bullet?

kind regrads

Ha,ha,ha! Are you joking!?
Gun bullets are usually made from lead (with or without brass or steel sleeve). Why should anybody want to reject lead? It is coloured metal with very nice features. Show me one metal detector on market with feature to reject lead!? Except some poor PI...

[metaldetector107]

TGSL Disc

Dear All
why doesnt TGSL reject gun bullet?

kind regrads

[ivconic]

I appreciate good advice, no problem anytime. Even criticism, what the heck.

I broke my rule and posted some ideas I should keep in separate thread so not confusing to anyone who is following the "tried and true" instructions.

I'm not worried about my own detector as I'm having fun experimenting. I can always return to "exact spec", no problem.

My goal is to learn how to "tune" best, even if deviate from exact spec. For example, I made some coils with very low resistance (7 ohms). Causes problems for sure, but I think there is a way to compensate. But I'll keep results in separate thread because it is confusing, I agree.

I also want to use TGSL as basis for alternate designs. For example, slower reponse version; 180 deg disc version; "simple" notch version; dual response version; super-tune resonant version; etc. Just some ideas that pop in mind -- but I have to keep reminding myself -- SEPARATE THREAD!

Another goal I have is trying to try easy construction methods when don't have good tools or shop. Sometimes funny, usually don't work, but maybe useful to somebody someday -- separate thread!.

But anyway, I'm interested if Ultimate Haze can make handmade TGSL go deeper and how done.

Regards,

-SB

Yes i support and understand your attitude. Besides...i experimented much also. Thinking......again must be the coil, cose really original TX/RX at TGS does not need some modifications, it works very clean and good. Like i posted so many times in the past; i dont like only audio part at it.
TGS/TGSL needs mostly better audio. I gained better audio...much better, with last BD140 mod. Yet...it is half way to become good. Not satisfied yet.
I would be more happy to see various ideas on that subject here.
TGS/TGSL the way it is projected now is splendid coinshooter. Maybe needs more power to go deeper on larger items and for sure needs much better audio. I am to much occupied latelly to continue my works on it. Also Eldorado now looks more promising to me. If i ever continue to deal with that i will rather take Eldorado as starting platform for experimenting.
Cheers!

[simonbaker]

Simonbaker,



That definitely works +3 сm for my TGSL with adjusting of TX frequency with the C2 capacitor. About 28 cm for 1 euro coin after this adjustment. Thanks!

I think that the original sound with MPSA 14 transistor is a little noisy in home conditions.

It may have nothing to do with my reasoning, but glad you have more depth! I know you tried increasing C6 which should be similar but you found not stable, so for some reason this worked. Sometimes just resolder improves!

What frequency change did you make (from-to)?

-SB

[Aiko]

Simonbaker,

3. TX frequency -- if too far from RX resonant frequency, you lose gain. You can either raise the TX frequency (by lowering inductance of TX coil, or decreasing capacitor C2 .022 uF) or you can also lower the RX resonant frequency by increasing capacitor C6 (.015 uF) or increasing inductance of RX coil. This increases gain, but watch out, if you go too far you alter phase of target signals and discrimination won't work well.

That definitely works +3 сm for my TGSL with adjusting of TX frequency with the C2 capacitor. About 28 cm for 1 euro coin after this adjustment. Thanks!

I think that the original sound with MPSA 14 transistor is a little noisy in home conditions.

[simonbaker]

OK,
Max.
Tks.
I will do as you say.So you advice me to try with less turns,so I can reach higher freq.?Haven't noticed but its rely too low indeed.
Made a funny test today.Changed BF245C with PN4393.The frequency now with same coils is around 24,4kHz.Better iron disc and a little sense.Now 24-26cm.But its too wrong 24,4!Gonna solder BF245C back.
Problem is coil for shore.I try to reach 6,00 and 6,5mH inductance and forget to look at tx freq.
But with last former posted here in pdf I made 110 TX windings to reach 6,0mH and around 112-114 for TX 6,5.And they should be TX 100/ RX 105 right?With this setup not good results so far.And I get wrong inductance.

Where are you using BF245C and PN4393? Are you sure you measure freq correctly?


Regards,

-SB

[simonbaker]

I dont want to bug you here, but really dont understand what is the problem with your handmades??? So many tries so far???
Could be coil, but also could be anything else. In most of the cases chatters DO appears if coil is not made well. In most ... - not in all cases.
Inside the house or outdoor - you MUST NOT have chatters at all. When sense adjusted to maximum - the same, you must not have chatters. Chatters...but very rare and mum can appear ONLY on some not so oftenly met areas on soil, where certain mineralisation is presented in higher percentage, even than only if Sense is on maximum.
Also i do not understand all those "philosophy" you elaborated here so far???
Can't you simply obey given datas? You have 100% accurate schematic posted many times here on this thread. Also you have few very good pcb's, tested and aproved in many (32 cases so far at me) cases. Coil....coil is not piece of cake to make...yet, again, it is not so hard to make also. Simply use proper wire and on given former achieve 6 and 6.5mH and that is all. Apply Al shield, leave 1cm gap, connect those as on given sketch and balance it with patience.
Ok...for now DO forget nulling with scope or millivoltmeter. Just forget that. Null it just with coin. Swing coin over it and null it, again and again. Try to achieve best distance in air. You simply must gain 30cm on 1e coin cose it is the least you will have to achieve. Inches above 30cm are success, usually gained if everything else already done perfect. But 30 cm on 1e coin in air is starting point - least that you will have to achieve.

Do NOT change neither one component value from given schematic.
Reading some post here i saw that you already experimented with some components values and changed wildly!?!? Why? Who told you to do that?
No wonder why you confused yourself more and more.
Now is a hell of task to return it to good setup and to balance coil to work good.
Usually that's the case when experimentator "overexperiment" to much. Dont ask me how i know that!

Hopefully you will not understand this as bad attitude but as positive and productive criticism in hope to help you to solve the problem.
Regards!

I appreciate good advice, no problem anytime. Even criticism, what the heck.

I broke my rule and posted some ideas I should keep in separate thread so not confusing to anyone who is following the "tried and true" instructions.

I'm not worried about my own detector as I'm having fun experimenting. I can always return to "exact spec", no problem.

My goal is to learn how to "tune" best, even if deviate from exact spec. For example, I made some coils with very low resistance (7 ohms). Causes problems for sure, but I think there is a way to compensate. But I'll keep results in separate thread because it is confusing, I agree.

I also want to use TGSL as basis for alternate designs. For example, slower reponse version; 180 deg disc version; "simple" notch version; dual response version; super-tune resonant version; etc. Just some ideas that pop in mind -- but I have to keep reminding myself -- SEPARATE THREAD!

Another goal I have is trying to try easy construction methods when don't have good tools or shop. Sometimes funny, usually don't work, but maybe useful to somebody someday -- separate thread!.

But anyway, I'm interested if Ultimate Haze can make handmade TGSL go deeper and how done.

Regards,

-SB

[ivconic]

Rule no. 1:

1) Mechanical stabillity = electronical stabillity.

....

[ivconic]

Hi,
yes, newer PCBs are less noisy than original. TGSL stuff is then already silent with all original pieces in place, if coil it's OK.

The problem are old PCBs, like original one (page #1): it has notch stuff... and things are really close. If no component selection is made or notch section isn't unpopulated the noise generated will easy propagate to other stages resulting in big chatters at speaker in max sens position.

Also, I made Vladimir's PCB too... neat, small one... but similar problem: things are too close one each other... resulting in additional noise.

The solutions there are... but , sure, TGSL pcbs are far easier than hacking old boards...

In all cases the perfect coil is mandatory if wanna max performance... but, in spit there's all here about data, seems just few people really made it good !

I don't know what to say about... maybe required skills are a way too high for average homebrewer ???

Strange!

Kind regards,
Max

Not really, of course not. This requires average skills and average equipment in amateur workshop. What really requires are patience , trim and neat work. I am usually a Serbian...but when comes to electronic works and crafting, than i usually turn to ortodox German! Maybe that is my only secret!?

[Max]

I dont want to bug you here, but really dont understand what is the problem with your handmades??? So many tries so far???
Could be coil, but also could be anything else. In most of the cases chatters DO appears if coil is not made well. In most ... - not in all cases.
Inside the house or outdoor - you MUST NOT have chatters at all. When sense adjusted to maximum - the same, you must not have chatters. Chatters...but very rare and mum can appear ONLY on some not so oftenly met areas on soil, where certain mineralisation is presented in higher percentage, even than only if Sense is on maximum.
Also i do not understand all those "philosophy" you elaborated here so far???
Can't you simply obey given datas? You have 100% accurate schematic posted many times here on this thread. Also you have few very good pcb's, tested and aproved in many (32 cases so far at me) cases. Coil....coil is not piece of cake to make...yet, again, it is not so hard to make also. Simply use proper wire and on given former achieve 6 and 6.5mH and that is all. Apply Al shield, leave 1cm gap, connect those as on given sketch and balance it with patience.
Ok...for now DO forget nulling with scope or millivoltmeter. Just forget that. Null it just with coin. Swing coin over it and null it, again and again. Try to achieve best distance in air. You simply must gain 30cm on 1e coin cose it is the least you will have to achieve. Inches above 30cm are success, usually gained if everything else already done perfect. But 30 cm on 1e coin in air is starting point - least that you will have to achieve.

Do NOT change neither one component value from given schematic.
Reading some post here i saw that you already experimented with some components values and changed wildly!?!? Why? Who told you to do that?
No wonder why you confused yourself more and more.
Now is a hell of task to return it to good setup and to balance coil to work good.
Usually that's the case when experimentator "overexperiment" to much. Dont ask me how i know that!

Hopefully you will not understand this as bad attitude but as positive and productive criticism in hope to help you to solve the problem.
Regards!

Hi,
yes, newer PCBs are less noisy than original. TGSL stuff is then already silent with all original pieces in place, if coil it's OK.

The problem are old PCBs, like original one (page #1): it has notch stuff... and things are really close. If no component selection is made or notch section isn't unpopulated the noise generated will easy propagate to other stages resulting in big chatters at speaker in max sens position.

Also, I made Vladimir's PCB too... neat, small one... but similar problem: things are too close one each other... resulting in additional noise.

The solutions there are... but , sure, TGSL pcbs are far easier than hacking old boards...

In all cases the perfect coil is mandatory if wanna max performance... but, in spit there's all here about data, seems just few people really made it good !

I don't know what to say about... maybe required skills are a way too high for average homebrewer ???

Strange!

Kind regards,
Max

[ivconic]

I dont want to bug you here, but really dont understand what is the problem with your handmades??? So many tries so far???
Could be coil, but also could be anything else. In most of the cases chatters DO appears if coil is not made well. In most ... - not in all cases.
Inside the house or outdoor - you MUST NOT have chatters at all. When sense adjusted to maximum - the same, you must not have chatters. Chatters...but very rare and mum can appear ONLY on some not so oftenly met areas on soil, where certain mineralisation is presented in higher percentage, even than only if Sense is on maximum.
Also i do not understand all those "philosophy" you elaborated here so far???
Can't you simply obey given datas? You have 100% accurate schematic posted many times here on this thread. Also you have few very good pcb's, tested and aproved in many (32 cases so far at me) cases. Coil....coil is not piece of cake to make...yet, again, it is not so hard to make also. Simply use proper wire and on given former achieve 6 and 6.5mH and that is all. Apply Al shield, leave 1cm gap, connect those as on given sketch and balance it with patience.
Ok...for now DO forget nulling with scope or millivoltmeter. Just forget that. Null it just with coin. Swing coin over it and null it, again and again. Try to achieve best distance in air. You simply must gain 30cm on 1e coin cose it is the least you will have to achieve. Inches above 30cm are success, usually gained if everything else already done perfect. But 30 cm on 1e coin in air is starting point - least that you will have to achieve.

Do NOT change neither one component value from given schematic.
Reading some post here i saw that you already experimented with some components values and changed wildly!?!? Why? Who told you to do that?
No wonder why you confused yourself more and more.
Now is a hell of task to return it to good setup and to balance coil to work good.
Usually that's the case when experimentator "overexperiment" to much. Dont ask me how i know that!

Hopefully you will not understand this as bad attitude but as positive and productive criticism in hope to help you to solve the problem.
Regards!

[Max]

I have the same problem -- easy to make detector that works around 20 cm, but I have not achieved 30+.

I am trying to study each part to understand. The experienced people say "coil", so probably that is the answer -- but what makes one coil wrong, another right? I want to study and see. So I'm making various coils. It will take some time.

One difficulty I have is electrical noise inside house. Final test must be outside away from power wires, with sensitivity pot turned most sensitive.

Question: when you use outside and turn sensitivity to most sensitive, do you hear "chatter", or is it quiet?



Are those voltages on the capacitors? They should not be negative. If they are negative, then you have "nulled" the coil incorrectly, you need to shift the coil slightly to other side of the null to get positive voltages.

Also, move the discrimination knob through full range, the voltages should stay positive over the whole range (at least most of it).

I have ideas I want to test.

1. Shielding -- the shielding can reduce depth. Maybe try less conductive shielding -- instead of foil, carbon paint, screen, etc. (Of course make sure shielding has gap!). Maybe try not shielding the TX coil at all.

2. RX coil resistance -- if too low, it may pick up extra noise at resonant frequency. If too high, reduces gain. Your value might be a little high, try slightly heavier wire to get around 20 ohms???? Who knows, it is something to experiment with.

3. TX frequency -- if too far from RX resonant frequency, you lose gain. You can either raise the TX frequency (by lowering inductance of TX coil, or decreasing capacitor C2 .022 uF) or you can also lower the RX resonant frequency by increasing capacitor C6 (.015 uF) or increasing inductance of RX coil. This increases gain, but watch out, if you go too far you alter phase of target signals and discrimination won't work well.

4. You can try "tuning the null" by swinging a coin above coils and adjusting the null for maximum depth. I don't know why this works exactly; theory says if you are close to null it shouldn't make much difference to motion detector. I would make sure voltages on C12, C15 are positive.

5. Gain -- if you have no "chatter" or noise sounds when sensitivity pot is maximum, then maybe you can increase gain of the RX signal. Techniques include lower resistance of RX coil; lower resistance of TX coil; move RX resonance closer to TX oscillator frequency; maybe play with gain of LF353 by increasing R15 220K, but could cause other problems;

6. Reduce sensitivity threshold -- if you have no "chatter" or noise sounds when sensitivity pot is maximum, then maybe you can decrease sensitivity threshold. This is not really recommended, but it might reveal something. This is done by shorting resister R37 (1k) connected to sensitivity pot.

7. Different diameter coil -- I am making 26-27 cm coils. I think big enough, but who knows. Maybe smaller would work better with some coin???

8. Check discrimination driver phase (LM393 output) -- wrong phase could reduce gain.

I think it is important to distinguish between two problems 1) noise, 2) gain. They require different solutions. If too noisy, must identify where noise coming from; coil or circuit? Jitter in oscillator? etc. If gain, then look at ways to increase gain as above.

I'll keep trying. Please keep us updated on your progress.

Regards,

-SB

Hi,
occasional chatters are heard at max sens, but that depend on too many things.

If have too much noise inside home (like fluorescent/energy-saving lamps) it's a problem... device catch them also.... no problem....

also switching supply stuff...tv sets etc.

If use wrong/noisy components device will start making its own internal noise ruining all tuning: a thing to stay far is TL062... beware! NOISY stuff.

But there's a way to keep it silent : component selection... lower noise parts.

That works if you have small noise inside home.... you easy see 30+ cm for a coin.

Of course, coil is the key in performance... so with a bad coil you'll have just average or poor performances.

Kind regards,
Max

[Ultimate_Haze]

OK,
Max.
Tks.
I will do as you say.So you advice me to try with less turns,so I can reach higher freq.?Haven't noticed but its rely too low indeed.
Made a funny test today.Changed BF245C with PN4393.The frequency now with same coils is around 24,4kHz.Better iron disc and a little sense.Now 24-26cm.But its too wrong 24,4!Gonna solder BF245C back.
Problem is coil for shore.I try to reach 6,00 and 6,5mH inductance and forget to look at tx freq.
But with last former posted here in pdf I made 110 TX windings to reach 6,0mH and around 112-114 for TX 6,5.And they should be TX 100/ RX 105 right?With this setup not good results so far.And I get wrong inductance.