TESORO GOLDEN SABRE

[Max]

Hi Max.
Yesterday on field test, i experimented with GEB setting. When i set up geb to a level where ground balance was ok, TGS detect all coins, but when you try to detect a bigger pice of metal, like 10 by 4 cms. this detection was at about 4 cms. Then when you set back geb to it´s original position you can detect it at about 35 cms, but ground balance not good, losts of noises. Do you know anything about this or should i experiment with geb to the rest of it settings, cause this whas tested to a half of pot geb setting.
I m also purchasing 125 LM308 at 45 cents each.
Regards
Nelson

Hi,
LM308 have nothing to do with what you experienced. It's the same with 308 or e.g. TL081 about this thing.

ApBerg and Quiaozhi gave you a good informations about what happens... look at silver response... I've made this test and it's reliable you must detect large silver coins and reject a ferrite stick or ring at say 5cm from coil. If not you'll have troubles on the real ground. I suggest you tune it for a medium soil where you know there is small mineralization due to iron oxides... but not too high cause otherwise you'll actually overbalance it.

You have to reach a point where raising or lowering the coil (fast) from soil would not give any false signal in a point you have tested there isn't any metal buried. You can use another detector first to be sure there isn't metal and then tune geb trimpot of TGS.

It's not easy at first attempt but you must repeat some times to be sure of your setting.

Then another thing... TGS have GEB pot on PCB so it's not like bandidoII that has an external fine GEB pot for all kind of terrains... so you have to use a panel-pot if you plan to use TGS in too different soils with e.g. heavy mineralization etc cause otherwise you'll be surprised by too many false signals... but I noticed that GEB work good in a wide interval of conditions and just extreme need adjusting... but I'll wonder if these fixed-settings are good e.g. for australian soils!

Nelson BTW what about weight of your TGS assembly , with coil and everything ?

Kind regards,
Max

[nelson]

Hi Max and thanks for such information about geb.

About my TGS weigth, this is about 1.5 to 2 kg. The main support is made of aluminium and pvc. The detector case is the one show on my picture id posts, made on a pvc box with transparent cover, so you can see the circuit inside. The coil is housing on a piece of polyethene form, that you can molded to any shape you whant, very easy. I also use a plactic flowers base to hold the coils inside. The 12 volts, 1.2 amp battery is allocated on a pvc housing too.
That´s it

Regards

Nelson

Hi,
LM308 have nothing to do with what you experienced. It's the same with 308 or e.g. TL081 about this thing.

ApBerg and Quiaozhi gave you a good informations about what happens... look at silver response... I've made this test and it's reliable you must detect large silver coins and reject a ferrite stick or ring at say 5cm from coil. If not you'll have troubles on the real ground. I suggest you tune it for a medium soil where you know there is small mineralization due to iron oxides... but not too high cause otherwise you'll actually overbalance it.

You have to reach a point where raising or lowering the coil (fast) from soil would not give any false signal in a point you have tested there isn't any metal buried. You can use another detector first to be sure there isn't metal and then tune geb trimpot of TGS.

It's not easy at first attempt but you must repeat some times to be sure of your setting.

Then another thing... TGS have GEB pot on PCB so it's not like bandidoII that has an external fine GEB pot for all kind of terrains... so you have to use a panel-pot if you plan to use TGS in too different soils with e.g. heavy mineralization etc cause otherwise you'll be surprised by too many false signals... but I noticed that GEB work good in a wide interval of conditions and just extreme need adjusting... but I'll wonder if these fixed-settings are good e.g. for australian soils!

Nelson BTW what about weight of your TGS assembly , with coil and everything ?

Kind regards,
Max

[Max]

Hi Max and thanks for such information about geb.

About my TGS weigth, this is about 1.5 to 2 kg. The main support is made of aluminium and pvc. The detector case is the one show on my picture id posts, made on a pvc box with transparent cover, so you can see the circuit inside. The coil is housing on a piece of polyethene form, that you can molded to any shape you whant, very easy. I also use a plactic flowers base to hold the coils inside. The 12 volts, 1.2 amp battery is allocated on a pvc housing too.
That´s it

Regards

Nelson

Hi Nelson,
thanks for the informations. My actual weight is 1.9Kg with gel-cell 12v 1.2Ah
and 1.63Kg with 10 NiMh cells ...the weight of lead-acid battery cell is around 450gr cause of lead... but at now I mount it for tests.

I'm searching for some spare materials that could save some weight cause a 1.9Kg one is ok... but e.g. 1.2Kg is much better for e.g. shoulder/arm for long run.

I think I can change the pole with PVC or better some fishrods-like carbonium/composite stem to save weight and keep pole very rigid... but for now just thoughts and ideas. I think I can gain 300gr less from that.

Best regards,
Max

[nakky]

stem

Hi Max,I use onefoot photo-tripod very light.Grt Nakky.

[erolunall]

manuel

hello all

http://www.tesoro.com/LoboSuperTraq_Manual.htm

link is manuel for a tesero model
best wishes
Erol

[Max]

Hi Max,I use onefoot photo-tripod very light.Grt Nakky.

Hi Nakky,
thanks for the info. I think I could find one of the same type very easy and so saving some more weight.

Kind regards,
Max

PS: commercial name is "monopod" or "unipod" for these single-leg devices... I have in mind a place where I saw 3 or 4 different models... very light: thanks again for the hint.

[Qiaozhi]

Hi Nelson,
thanks for the informations. My actual weight is 1.9Kg with gel-cell 12v 1.2Ah
and 1.63Kg with 10 NiMh cells ...the weight of lead-acid battery cell is around 450gr cause of lead... but at now I mount it for tests.

I'm searching for some spare materials that could save some weight cause a 1.9Kg one is ok... but e.g. 1.2Kg is much better for e.g. shoulder/arm for long run.

I think I can change the pole with PVC or better some fishrods-like carbonium/composite stem to save weight and keep pole very rigid... but for now just thoughts and ideas. I think I can gain 300gr less from that.

Best regards,
Max

The Tesoro Lobo SuperTraq seems to be much heavier than expected at 1.59Kg.
Whereas a Garrett GTAx1000 is 1.48Kg, a Bandido (not uMax) is 1.36Kg, and a Nexus Coronado is 1.3Kg by comparison.

[nakky]

stem

Hi Nakky,
thanks for the info. I think I could find one of the same type very easy and so saving some more weight.

Kind regards,
Max

PS: commercial name is "monopod" or "unipod" for these single-leg devices... I have in mind a place where I saw 3 or 4 different models... very light: thanks again for the hint.

Hi Max ,oke monopod or unipod,but with a tripod you have 3 stems Grt Nakky

[Max]

The Tesoro Lobo SuperTraq seems to be much heavier than expected at 1.59Kg.
Whereas a Garrett GTAx1000 is 1.48Kg, a Bandido (not uMax) is 1.36Kg, and a Nexus Coronado is 1.3Kg by comparison.

Hi,
yes... some tesoro's are not 2.2lb like "light" models but something around 1.5Kg or even more (e.g. Tejon, Cortes) that mean +50% or more in weight.

It's normal they are a bit more heavy cause of bigger e.g. case and similar... but +50% is great problem... also coils have some differences from e.g. the uMax series.

Nexus seems have a very good weight-vs-performances.

I'm really puzzled by Minelab's weights and Coiltek of course... too heavy for my taste.
More weight on coil is also more and more forces on the shoulder/arm... cause of the shape of detectors and the fact that coil have to float at near-to-constant height from soil.

What do you think of coiltek ones ?

Best regards,
Max

[ivconic]

!

"Problem is solved!..."
Well....not complete! I took last finished TGSL on the field with me yesterday.
Yes it is good and deep. I found 254 small roman coins, working 5-6 hours there!!!
It is top record for me! So far!
This device is without 1M resistor.No more loud and often bleeping but still there
are ocassional short decayed "tic-tic"!?
I obey what Max suggested and tried to more precise adjust GND trimmer there - on the
real field, under real conditions. But...!? Still if i pull up and lower down coil fast
to the ground, device is producing some false signals...? I tried several times, no way
to adjust it not to produce false signals at all!? In my workshop it is not reacting on
pure ferrite bar at all...Absolute calm, no false signals at all.
This returns me again to suspect on coil!? Horror! Coils are nulled on already described
way. Measuring with very good multimeter while nulling. At the end coils are nulled to
point where i have 0.000-0.001v AC on RX ends... I simply connect meter with RX coil ends
without adding capacitor and resistor Max talked about. Could this be a mistake?
I have some old,obsolete scope...When testing with it i just cant null coil fine due small
resolution of scope itself.
This latest behavior is not disturbing much for user. Bleeps are rare and ocassional.Also
audio volume when bleeps is very low, so it is very easy to distinguish among right detection
and false signal.But.....i am not satisfied with this...i want to find out what is problem
and to better understand this.
There is a way to stop this - lower Sensitivity to 50% pot scale...After that, device is very
calm. Only produce again very short decayed bleep if coil hit some rock or bulky grass arround.
Even than it is at very low audio level..very silent...
First thought was; it must be arround coil...? But i am not sure.
Second idea occured me is; could it be due Al foil cage over coil? Maybe all this came from
Al foil? I have no condition to make Faraday cage from other,better material ..so far.So i
used self adhesive Al foil tape..

[Qiaozhi]

"Problem is solved!..."
Well....not complete! I took last finished TGSL on the field with me yesterday.
Yes it is good and deep. I found 254 small roman coins, working 5-6 hours there!!!
It is top record for me! So far!
This device is without 1M resistor.No more loud and often bleeping but still there
are ocassional short decayed "tic-tic"!?
I obey what Max suggested and tried to more precise adjust GND trimmer there - on the
real field, under real conditions. But...!? Still if i pull up and lower down coil fast
to the ground, device is producing some false signals...? I tried several times, no way
to adjust it not to produce false signals at all!? In my workshop it is not reacting on
pure ferrite bar at all...Absolute calm, no false signals at all.
This returns me again to suspect on coil!? Horror! Coils are nulled on already described
way. Measuring with very good multimeter while nulling. At the end coils are nulled to
point where i have 0.000-0.001v AC on RX ends... I simply connect meter with RX coil ends
without adding capacitor and resistor Max talked about. Could this be a mistake?
I have some old,obsolete scope...When testing with it i just cant null coil fine due small
resolution of scope itself.
This latest behavior is not disturbing much for user. Bleeps are rare and ocassional.Also
audio volume when bleeps is very low, so it is very easy to distinguish among right detection
and false signal.But.....i am not satisfied with this...i want to find out what is problem
and to better understand this.
There is a way to stop this - lower Sensitivity to 50% pot scale...After that, device is very
calm. Only produce again very short decayed bleep if coil hit some rock or bulky grass arround.
Even than it is at very low audio level..very silent...
First thought was; it must be arround coil...? But i am not sure.
Second idea occured me is; could it be due Al foil cage over coil? Maybe all this came from
Al foil? I have no condition to make Faraday cage from other,better material ..so far.So i
used self adhesive Al foil tape..

Hi Ivconic,

There is an easy way to find out if the problem is in the detector or in the coil. Why not test your TGS using an original Tesoro coil?
Personally I would be suspicious of the shielding in the coil. You can also try using an electrostatic sheet in the base of the coil housing. Garrett do this in their Crossfire coils. The sheet is then connected to the coil screen via a large spring that presses on the sheet.

[Max]

"Problem is solved!..."
Well....not complete! I took last finished TGSL on the field with me yesterday.
Yes it is good and deep. I found 254 small roman coins, working 5-6 hours there!!!
It is top record for me! So far!
This device is without 1M resistor.No more loud and often bleeping but still there
are ocassional short decayed "tic-tic"!?
I obey what Max suggested and tried to more precise adjust GND trimmer there - on the
real field, under real conditions. But...!? Still if i pull up and lower down coil fast
to the ground, device is producing some false signals...? I tried several times, no way
to adjust it not to produce false signals at all!? In my workshop it is not reacting on
pure ferrite bar at all...Absolute calm, no false signals at all.
This returns me again to suspect on coil!? Horror! Coils are nulled on already described
way. Measuring with very good multimeter while nulling. At the end coils are nulled to
point where i have 0.000-0.001v AC on RX ends... I simply connect meter with RX coil ends
without adding capacitor and resistor Max talked about. Could this be a mistake?
I have some old,obsolete scope...When testing with it i just cant null coil fine due small
resolution of scope itself.
This latest behavior is not disturbing much for user. Bleeps are rare and ocassional.Also
audio volume when bleeps is very low, so it is very easy to distinguish among right detection
and false signal.But.....i am not satisfied with this...i want to find out what is problem
and to better understand this.
There is a way to stop this - lower Sensitivity to 50% pot scale...After that, device is very
calm. Only produce again very short decayed bleep if coil hit some rock or bulky grass arround.
Even than it is at very low audio level..very silent...
First thought was; it must be arround coil...? But i am not sure.
Second idea occured me is; could it be due Al foil cage over coil? Maybe all this came from
Al foil? I have no condition to make Faraday cage from other,better material ..so far.So i
used self adhesive Al foil tape..

Hi Ivconic,
I think problem could be in the circuit and not coils... of course I never used one of your coils but we use about same materials and I've made a coil for TGS like yours (255x137) following your specs. And I think yours are great/good coils.

Also I have original tesoro coil 9x8 I bought and behaviour is the same with same components on PCB, so at least for me, bleeping is not related to coils.

What I noticed is:

LM308N, that's very good about depth on this design, actually introduce some more bleeping than TL081. Less with LM308AH version but you know is very expensive and hard to find.
That's a big drawback... you gain depth cause of different input stage etc but you lose also cause of erratic bleeping, cause have to keep sens pot at lower setting.
Think that solution to this problem is finding some good op. amp. with bipolar inputs and with much better noise figure than 308... but it's really hard and I have no idea at the moment.

If notch section is present other bleeping is related to the bad choice of TL062 that's a very old and noisy IC: I have changed with TLC2262 from TI... and fixed that.

The fets introduce noise spikes in the signal path cause of their commutation. Using BF245 problem is not enormous but one can see very well on scope. I think that's not a big issue cause that noise is syncronous... but other sources (like 308s) give random spikes.

Also if coils are out null for more than 4-5mVpp I noticed and increase in noise with same components... otherwise not.

Circuit need extreme cleaning (like many other MD boards) cause of the hi amplification.

If you have near a noise source like electric interferences, fluorescent-lamps etc TGS with also original coil could give lot of false signals... even if coils are perfectly shielded.

I think that if you have to keep sens at 50% to avoid bleeping you probably have some "bad" component on your boards: I mean for "bad" a too noisy one.

I suggest you check the LM308s and LM358 for on-board noise you'll ear on the field.

About GEB and total null ...well, it works, but in middle soils much better than others with too iron oxides.

Best regards,
Max

[Qiaozhi]

Are you certain that the comparators are not going into oscillation? This would cause the exact symptoms you are experiencing.

[Unregistered]

Hi
Anyone have an idea of the influence of gap position in the shield to the performance of the coil? i mean , where is the best place for the wires to com out from the coil, so the interaction is minimal ?
Maybe this make no diference,but...
Fred.

[Qiaozhi]

Hi
Anyone have an idea of the influence of gap position in the shield to the performance of the coil? i mean , where is the best place for the wires to com out from the coil, so the interaction is minimal ?
Maybe this make no diference,but...
Fred.

I do not think the gap position will have any noticeable effect on the performance of the coil. It's just important that there is a gap.