TESORO GOLDEN SABRE

[sonar]

i send the file on Your PM Max... have fun or delete it

[Max]

hmmm. no problem




its was test only remember
nothing sure... frequency and others...

Hi,
the 5ms transient an. time limit is wrong: use 20ms or better 50ms.

At 5ms you could see amplitude before stabilization... so a sharp and tall peak of voltage that then drop after to real values.

Now see my simulation using a custom (MAX20 ) 20v zener diode (not in shops unfortunately ) and 24V positive supply.

Big wave, but too distorted for my taste and also one need 24v there... not good stuff to test on real circuit.

Kind regards,
Max

[sonar]

sorry. i make test on 5m like on your circuit

on 5m - BZX84C15L work great too

all clear now

but on 50 its not look soo good

thanks for solution Max...

[Max]

sorry. i make test on 5m like on your circuit

on 5m - BZX84C15L work great too

all clear now

but on 50 its not look soo good

thanks for solution Max...

Hi,
you are welcome... now that I dug that files I can start thinking at it again...

I was thinking some months ago of putting more power there but then something happened and I switched to other projects... nice to see there are still people interested in the topic.

The big problem is that the colpitts osc there is not a great solution about power delivered. Also I'm worried that trying to put 30 or more Vpp on coil will make device unstable on soil... cause one need really perfect GEB to deal with that stuff on little hot soil ...with fragments and magnetic compounds.

Anyway, I will test a bit on it with my TGSlight board (I never totally tuned/completed so far!).

Kind regards,
Max

[Aziz]

Hi Max,

if you need more power from LC-osc, look at some maxwell-bridges. A very simple LC osc with maxwell-bridge + fast OPamp + driving transistors can deliver much more power.
I measured a ca. 650 Vpp with such an high power LC-osc on the coil!!! So, the amplifier stage can be neglected. You need a good attenuator on the RX-coil!
;-)
Regards,
Aziz

[Max]

Hi Max,

if you need more power from LC-osc, look at some maxwell-bridges. A very simple LC osc with maxwell-bridge + fast OPamp + driving transistors can deliver much more power.
I measured a ca. 650 Vpp with such an high power LC-osc on the coil!!! So, the amplifier stage can be neglected. You need a good attenuator on the RX-coil!
;-)
Regards,
Aziz

Hi,
thanks I will keep in mind.

Don't know how much voltage put there without making a big mess....
but I will make some test and see what happens on TGSlight.

Kind regards,
Max

[sonar]

Theories is only good start and all of them sounds like good story from fables.

Good test is only way to true - but in practice life is very brutal for metal detector designes

We have no hope - but we can still try to start a new experiments...

[scevlik]

Hi!
I fineshed my TGS.Now I need only good coil.Please what is the best coil type and how meny turns i must made.

Thanks and sorry for my English

[Molzar]

Rx Phase shift

This is not because your RX coil leads are reversed. It is because your coil is under-nulled, rather than over-nulled. During the nulling procedure, as you move the two coils together (I assume it's a DD configuration) the residual RX voltage will be reduced. You need to pass through this minimum and null your coils on the other side of this zero-voltage point. In other words - on one side of the null, all metal targets gives a phase-shift to the right, and on the other they give a phase-shift to the left. Although you can get both configurations to work, the left phase-shift position gives the most sensitivity and better discrimination.

Hello,

Recently completed TGS and am now trying to tune it properly.

I also get Rx phase shift to the right when triggering on the Tx. I tried Qiaozhi suggestion of under / over nulled coil. This changes the amplitude charateristic (goes higher only (over nulled?), goes lower than higher (undernulled?) but the Rx always moves to the right vs the Tx.

The above happens when metal is in the overlapped area of the DD.

When the metal is in the other area of the coils it does shift somewhat to the left.

What am I doing wrong?

Molzar

[Max]

Hi!
I fineshed my TGS.Now I need only good coil.Please what is the best coil type and how meny turns i must made.

Thanks and sorry for my English

Hi,
use Ivconic's data:

TX= 100turns
RX= 105turns

wire 30AWG (0.25mm bare diameter, without varnish); you can use 0.30mm but require change a bit turns.

Coil diameter will be around 27cm DD type.

Null at less than 15mV peak-peak

Resistance is for each coil... around 20ohm and you have match tx frequency of 14.5 - 14.7Khz.

Kind regards,
Max

[Max]

Hello,

Recently completed TGS and am now trying to tune it properly.

I also get Rx phase shift to the right when triggering on the Tx. I tried Qiaozhi suggestion of under / over nulled coil. This changes the amplitude charateristic (goes higher only (over nulled?), goes lower than higher (undernulled?) but the Rx always moves to the right vs the Tx.

The above happens when metal is in the overlapped area of the DD.

When the metal is in the other area of the coils it does shift somewhat to the left.

What am I doing wrong?

Molzar

Hi,
I'm not sure... but think Qiaozhi report is valid only for concentric coplanar coils, expecially original tesoro's ones.

I have a 9x8'' spider from tesoro and on my TGS I see RX signal go to the left not to the right, as Qiaozhi stated.

Probably also you have reversed rx leads, try to swap them and let us know if it goes to the left then.

Kind regards,
Max

[erolunall]

Hello

good quality tgsl pictures at links


http://www.postimage.org/image.php?v=aV1OM0B9
http://www.postimage.org/image.php?v=aV1OLRCA
http://www.postimage.org/image.php?v=PqMil19

My friend said it is working good.

Regards
Erol

[zzy]

Molzar

Hi,
I'm not sure... but think Qiaozhi report is valid only for concentric coplanar coils, expecially original tesoro's ones.

I have a 9x8'' spider from tesoro and on my TGS I see RX signal go to the left not to the right, as Qiaozhi stated.

Probably also you have reversed rx leads, try to swap them and let us know if it goes to the left then.

Kind regards,
Max

Hi
My TGS is just like Molzar's. MAXreversed rx leads,no change,still RX signal go to the right.mabe DD coil is not fit to TGS.

[Molzar]

Phase shift

Hi Max,

Yes,I thought of that but the way coils are connected they give correct looking traces at all test points you outlined previously in posts.

The coils are DD 140 x 255 mm, 30 gauge enamled wire

Tx = 100 turns, 23.0 ohms, 5.78 mH, Q= 1.65
Rx = 105 turns, 24.1 ohms, 6.18 mH, Q= 1.67

Tx Freq =14.1 KHz

Nulls down to about 8 mV using 1K res / .015uF cap setup. Measure about 850 mV at the RX test point on the pcb.

Do your DD homebrew coils shift to the left also?

Left shift should be in All Metal and Discrimination mode, correct?

Molzar

[Max]

Hi Max,

Yes,I thought of that but the way coils are connected they give correct looking traces at all test points you outlined previously in posts.

The coils are DD 140 x 255 mm, 30 gauge enamled wire

Tx = 100 turns, 23.0 ohms, 5.78 mH, Q= 1.65
Rx = 105 turns, 24.1 ohms, 6.18 mH, Q= 1.67

Tx Freq =14.1 KHz

Nulls down to about 8 mV using 1K res / .015uF cap setup. Measure about 850 mV at the RX test point on the pcb.

Do your DD homebrew coils shift to the left also?

Left shift should be in All Metal and Discrimination mode, correct?

Molzar

Hi,
yes the shift is to the left on 9x8'' spider both ways, disc and all-metal.

Now I don't remember about DD, must check again but I remember that DD behave different... I remember that on my DDs I get left and right shifts depending on composition of target.

If remember well I get left shift with non-ferrous like copper and right shift with soft iron, or the reverse.

In the 9x8'' concentric coplanar I get instead like Qiaozhi said, always left: just amplitude rise with non-ferrous and drop with ferrous.

That's why I asked Ivconic about but didn't reply me...maybe didn't see my message: I think that in 9x8'' and other concentric-coplanar from Tesoro (originals) the only information about disc came from amplitude variation.

But seems nobody knows for sure.

Kind regards,
Max