TESORO GOLDEN SABRE

[tiktak]

Hi

hi,
Qiaozhi.
Sorry excuse my stupidity!

[Qiaozhi]

Hi,
I am BEGINER!
In this calculator there are inner diameter/I understand former size?!?/;wire thicknes and number of turns!
What is the (2*pi)?
I can't get the point?

Using "pi" was just an easy way to write "p".
The value of pi (p) is 3.14159
So 2*pi means "multiply pi by 2".

[tiktak]

Hi,

Hi,
Max.
Thanks.I uprishiate that you spend from your time to answer to all my questions.
About the 25DD I am still in frustration.You say ,try use less turns with respect to 28DD,but this 28DD use 120 for TX and 125 for RX!And 22DD use 145 for TX and 151 for RX?If I decrece the number of turns,I should increase the D of the winding?>???
I dont have LC meter!The only thing that I have for now is this multimeter.
Can I measure inductance with this?
The resistance should be from 19,XX to 22,XX ohms!But what should be te inductance?
Here is a stupid picture that I have tryed to show this coil housing dimensions!
That why I think that the former size should be 25cm??
Tomorrow I will have all the materials for making coil,so I am in a hurry!
I have replaced TL062 with TL072 for now,and there seems to be a differance.I have make some tests again with my first coil and looks like its better!Less noise

[Max]

HI,
MAX!!!
Please help.I can't find the right values for making this 25 cm coil!!
I now that you are curies too to see the results.I have only a few free days this year and wanna spend them making real field tests with this TGS!!!!
But still dont have coil!!I have bought very nice coil housing,but have to wind D with 25 cm diameter for former!I have data/thanks to YOU and IVCONIC/for 28cm coil and 22cm coil!But .................this 25cm coil is making me crazy?
Thanks
You were right!At the end it will work!!!
Very nice and easy to build,BUT VERY quality!!!Beat most of modern toys!
I will soon post the look of MY TGS.

Hi,
you have to use a smaller number of turns respect the ones used in 28cm.
To match right inductance.
I haven't data for it cause I don't make larger coils.
They don't suit my needs on VLFs.
At the moment also have really few time to experiment with coils and other stuff.

But I think it's easy to do. Really easy... the former isn't 25cm diameter !
Must be less... cause you use D shaped wounds.
Make first just TX wounding and get right inductance... then add 15% more turns to the RX wound.

Kind regards,
Max

BTW, yes TGS is a good project to homemade... easy and good performances... much better than some "TOYS" on the market at now.

[Max]

Ok Max i understand what you posted.
I heard that MD for gold nuggets usually TX on frequencies btw 14 and 30 Khz, but i m not shure wich frequencie is bether for gold nuggets.

My first 22 cms coil is TX on 19.2 Khz and the RX coil is calibrated to 19.1 Khz. I also replace the TX and RX leads that comes from PCB to the housing connector, with computer multifilar cable that has 4 wires, and a shield, with this my intermitent sound stops.
Today i tested my TGS on a local park. GEB calibration now functions good, no false signals, discrimination is working fine too. I got lots of coins in about an hour, i found 25 mm diameter copper coins btw 3 to 11 cms, sound was very strong, the soil surface is grass.
Tomorrow if i have the time, i ll try my second 22 cms coil to see how it performs.
What coil do you think i need for gold nuggets?
I know that gold nuggets detector need to be no movment, what about this TGS, can thias work for gold hunting if is it movment coil?
I saw on youtube some videos that shows detectors for gold nuggets that allways keep sounding and when you found a nugget the pitch change. What about TGS how i can get nuggets with it? How i do set upt it?

In advance many thanks

Nelson

Hi Nelson,
nice to ear it works good, geb and disc OK. Really nice to see that people here appreciate this little and older tesoro's design like I do... that sometimes also an old design and an homemade detector could give lot of satisfaction.
Cool.
Nelson you're right on nugget hunting detectors: most of them are no-motion !
But there are also motion types e.g. for Tesoro's I would talk about e.g. LOBO... that has motion search mode and no-motion just for pinpointing.

Anyway, you can search for nuggets also with GoldenSabre... and with good results. Often in nuggets detectors smaller coils are used:
4'', 5'', 6'' are examples of that
But I think you'll be fine with a DD22... if you'll search e.g. in river sand...flat surface and if you'll use a separate pinpointer.

No motion mode is used in tesoro's almost for pinpointing (e.g. in BandidoII)... so you just need a separate pinpointer and you could seach for nuggets, motion-mode using disc !

Of course, you can also use just GS... but small nuggets pinpoint is not easy sometimes. I suggest you'll use a separate pinpointer.

In earlier times there were lot of BFO/off-resonance to do the no-motion search for nuggets too.
That's the pitch change you notice in that: beating frequency.
Also some modern PI units used in gold-hunting use the VCO approach that is similar: pitch change.

I think you'll find your nuggets with your GSabre. That's my wish.

Best regards,
Max

[nelson]

Ok Max i understand what you posted.
I heard that MD for gold nuggets usually TX on frequencies btw 14 and 30 Khz, but i m not shure wich frequencie is bether for gold nuggets.

My first 22 cms coil is TX on 19.2 Khz and the RX coil is calibrated to 19.1 Khz. I also replace the TX and RX leads that comes from PCB to the housing connector, with computer multifilar cable that has 4 wires, and a shield, with this my intermitent sound stops.
Today i tested my TGS on a local park. GEB calibration now functions good, no false signals, discrimination is working fine too. I got lots of coins in about an hour, i found 25 mm diameter copper coins btw 3 to 11 cms, sound was very strong, the soil surface is grass.
Tomorrow if i have the time, i ll try my second 22 cms coil to see how it performs.
What coil do you think i need for gold nuggets?
I know that gold nuggets detector need to be no movment, what about this TGS, can thias work for gold hunting if is it movment coil?
I saw on youtube some videos that shows detectors for gold nuggets that allways keep sounding and when you found a nugget the pitch change. What about TGS how i can get nuggets with it? How i do set upt it?

In advance many thanks

Nelson

Hi Nelson,
I said 27cm depth (at now) with DD22 for 1eur coin....

1eur coin is about 23mm diameter, bimetallic coin.

With 1cm diameter coin (silver alloy) I get about your depth.

About disc... if you put much capacitance on the RX side... you'll lose some disc. That's why I said max 4-5nF increase or decrease respect to original 15nF.

You could experiment e.g. from 10 to 20 nF for rx cap. But if you keep it close to original and get good performances is even better.

Yes, changing the TX inductance change the frequency.

It's a colpitts osc. Formula is below.

Kind regards,
Max

[porkluvr]

!think!

Hi,
I have found LM3900 ,but its look like its not the same???!
What do you think?

Hmmm: It does not look like a duck, and it does not quack like a duck, and it does not swim like a duck - but it has two legs like a duck - so maybe it's a duck. What do you think! (sometimes I just can't help it!)
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
About your meter:
Tiktak, for the purpose of this discussion: in the voltage measuring mode, you are using a VOLTmeter. In the current measuring mode, you are using an AMPmeter. A milliameter is also an AMPmeter, but set to a low range.
So long as you make connections to CUT (circuit under test) as I tried to show in my picture, you should be OK.

Here's some theory you should already KNOW, but here it is again:

When measuring voltage, a VOLTmeter will present a high resistance to the CUT. You can connect a VOLTmeter across a 220V source, and only a small amount of current should flow through your meter because the actual resistance presented by your VOLTmeter is, ideally, very high.

That is not true when you measure current. An AMPmeter will present a very low resistance to the CUT. If you put your AMPmeter leads across a low impedance voltage source (such as a battery or voltage regulator output), something WILL smoke. All of the current that you allow, will flow through your meter - as determined by I=E/R (I = current, E = voltage, R = resistance). You must limit AMPmeter current with a resistor. That is why you need the 1k resistor in the null test circuit I showed you. You must not short out your opamp output, or else the measured result will be invalid.
And, there is the possibility of damage.

An AMPmeter (milliammeter, also) is approximately ZERO ohms resistance from one test lead to the other. It is a potential short circuit waiting to happen. Even one volt, or less, can theoretically cause infinate current to flow through zero ohms. Infinite current generally means something is bad, or will be soon.


So, what could happen if you want to measure a 12V battery with your multimeter, but you have your multimeter dial set to amps? In the milliamps mode you may only blow the multimeter's fuse. But, in the 10 amps mode, there is no fuse - and so you could either zilch the multimeter, or whatever you are measuring. Some meters have good overload protection circuits, less expensive multimeters usually do not. If you are careless in the AMPmeter mode, you might have to kiss your multimeter goodbye. Use the milliamp mode because it is fused. Fuses are relatively cheap, but they are not 100% effective - so you should still be careful.

An AMPmeter is approximately zero ohms from end to end, don't connect it anywhere that cannot handle a straight piece of wire! You don't place a jumper from one end of a battery to the other unless you want fire and smoke, do you? - it's the same idea.
Read your meter's instructions.

[tiktak]

HI

HI,
MAX!!!
Please help.I can't find the right values for making this 25 cm coil!!
I now that you are curies too to see the results.I have only a few free days this year and wanna spend them making real field tests with this TGS!!!!
But still dont have coil!!I have bought very nice coil housing,but have to wind D with 25 cm diameter for former!I have data/thanks to YOU and IVCONIC/for 28cm coil and 22cm coil!But .................this 25cm coil is making me crazy?
Thanks
You were right!At the end it will work!!!
Very nice and easy to build,BUT VERY quality!!!Beat most of modern toys!
I will soon post the look of MY TGS.

[tiktak]

Hi,

Hi,
porkluvr.
Thanks for the advice I will try this way because for now dont have other alternative.But please tell me what can I demage when measuring current?
The multimeter or metal detector?

Be careful when the meter in the milliamps test mode. I don't know your particular unit, but It may be more succeptible to damage. It is easy to blow a fuse - or worse when measuring current. You should definately THINK about what you are doing before you apply power, more so than usual.

How should I Measure AC current, instead of AC voltage?Put the multimeter in DCA 200m right???Or?
/look at the picture that I have post/
THANKS

[tiktak]

Hi

No - the calculator is not specifically for OO coils, but it is designed for circular coils. This means it is good for mono, OO or concentric coils. If you want to use it for calculating DD coils, then you need to do some mathematics.
First - estimate the circumference of the D coil you want to make. You can easily do this by laying out one turn of wire in the correct shape. Then measure the length of this one loop. If you were to reshape this loop into a circle, this is the size of coil you must enter into the calculator. In other words, take the length of the single loop and use this value as the circumference (C) for a circular coil. Then use R = C / (2*pi). The value R is the length of the radius to be entered in the calculator.
Lastly - wind the correct number of turns onto the D-shape. There is no need to wind a circular coil and reshape it, because the circumferences of both are the same.
And yes, there will be a margin of error, but after some practice you can work out the correct fudge factor.

Hi,
I am BEGINER!
In this calculator there are inner diameter/I understand former size?!?/;wire thicknes and number of turns!
What is the (2*pi)?
I can't get the point?

[tiktak]

Hi

Hi,
Leto.
I have found LM3900 ,but its look like its not the same???!
What do you think?

[Max]

Thanks Max.
Ok i ll do all that and see whats happend.

With the 15nF cap on RX coil leads, i got much sensitivity, but i also notice that on discrination, my wedding ring has almost no detction at minimum setting, while without the 15nF cap i get less sensitivity and my gold ring is detected at half turn on discrimination mode.

Perhaps all this, what else i can check to get more sensitivity. I ask this, cause you did 27 cm with 22 cms coil or this is ok. May be i need to check the TX stage to get more power, what do you think?
Another question, changing the TX coil inductance, changes the frequency too?
Do you have any formula to calculate the resonant frequency for the coil?

Regards

Nelson

Hi Nelson,
I said 27cm depth (at now) with DD22 for 1eur coin....

1eur coin is about 23mm diameter, bimetallic coin.

With 1cm diameter coin (silver alloy) I get about your depth.

About disc... if you put much capacitance on the RX side... you'll lose some disc. That's why I said max 4-5nF increase or decrease respect to original 15nF.

You could experiment e.g. from 10 to 20 nF for rx cap. But if you keep it close to original and get good performances is even better.

Yes, changing the TX inductance change the frequency.

It's a colpitts osc. Formula is below.

Kind regards,
Max

[porkluvr]

meter facts

Tiktak
I am sorry about the minimum order from Digikey. What country are you in where they want you to buy 2500 each??

Look, about your meter: what Leto said is correct - your multimeter's lowest voltage resolution is 100mV and that is not so great. But, you might still be able to use your meter. Measure AC current, instead of AC voltage.
It looks like your meter's current (amps) scale can resolve to 0.1 microamps. AC current resolution is good enough. A 10mV residual signal would push 10 microamps through a 1kΩ resistor, and that should be plainly readable on your meter's 200uA scale.

Now, this should work:
De-solder the ground end of the 1kΩ resistor on the far side of the .22 capacitor from the receiver opamp output. (look at the picture.) Connect the red meter lead there. Connect the black meter lead to PCB ground.

Using the existing 1kΩ resistor should give an OK trade-off between circuit loading and meter display resolution. Set the meter's scale to 200uA and null according to previous instructions.

With the suggested set-up using a 1k resistor, simply multiplying the measured current X1000 will tell you the AC voltage. This is an indirect method of measurement, but it should work reasonably well (unless the fuse in your meter is blown). So, now you may be able to afford to buy a better frequency counter (hmm, I need one too, come to think of it). $$Get a better multimeter some other day.

Be careful when the meter in the milliamps test mode. I don't know your particular unit, but It may be more succeptible to damage. It is easy to blow a fuse - or worse when measuring current. You should definately THINK about what you are doing before you apply power, more so than usual.

[Qiaozhi]

Hi,
Max.
I try but cant find right solution with this calculator....................
Its look like its for oo coils?
Please advice me.How much turns for this DD25cm./inner diameter 25cm/

No - the calculator is not specifically for OO coils, but it is designed for circular coils. This means it is good for mono, OO or concentric coils. If you want to use it for calculating DD coils, then you need to do some mathematics.
First - estimate the circumference of the D coil you want to make. You can easily do this by laying out one turn of wire in the correct shape. Then measure the length of this one loop. If you were to reshape this loop into a circle, this is the size of coil you must enter into the calculator. In other words, take the length of the single loop and use this value as the circumference (C) for a circular coil. Then use R = C / (2*pi). The value R is the length of the radius to be entered in the calculator.
Lastly - wind the correct number of turns onto the D-shape. There is no need to wind a circular coil and reshape it, because the circumferences of both are the same.
And yes, there will be a margin of error, but after some practice you can work out the correct fudge factor.

[Leto]

Originally Posted by tiktak
Leto,
This LM388 can't be found!!!
I spend all day going to all the stores that I now to search for this with no results!!!
I see that LM390 is similar can it be used?
Or LM3900?

I have not tried but it looks the same, also the pinout is identical..
download LM390 datasheet and you will see (FIGURE 1) same circuit I used...

about multimeters:
Your multimeter needs AC voltage range starting from 0mV (DT-830B starts with 100mv). Look for Max post somewhere about tuning with different multimeters there are quite big differences.
If you do not have frequency meter - that's also very much needed.