TESORO GOLDEN SABRE

[ivconic]

Hi,
few days ago I've tested my TGS with various coins...on air...and get good results with pure silver but a bit less with alloys.

I've tested with a 30mm diameter 925/1000 silver coin and got 39cm on air... then with another 30mm diameter but 825/1000 silver coin I got much less :
just 34cm on air.

The second coin has probably 165/1000 of copper and I think that influenced much reading about it.

Phase shift due to different metals seems mix in a way that make detection less easy !

I've seen before on other machines similar behaviour... very often with 50% silver coins.

34cm is not too bad for a 30mm coin...but also not a big distance: I'd like to know what do you think about... if you have similar problems e.g. when coinshooting in parks etc

Any comment welcome.

Kind regards,
Max

Yes Max, same with my devices! See my previous post. It has something to do with GEB&DISC part. Something is to "narrow" there? What?
Try to play a bit more with GEB trimmer - you will see huge differences...

[ivconic]

Alternative approach

So, i tried to setup alternative "zero" with this way of nulling coil. Why? TGS already have sufficient GEB&DISC adjustments...
Dirung working with TGSL under real conditions i noticed situatin on SOME fields TGSL cant be grounded well; it still can produce fast chatters ocassionally...similar with almost all other detectors.Even GT (which is very stabile) sometimes can jitter a bit. Despite all my love for TGSL i still have to say that its GEB is not perfect. When testing in workshop it can absolutely reject ferrite,iron and simillar....even that famous mineralized clay. But outdoor i noticed some jitters from time to time. To repeat; when handling with cable i cant provoke any falses, also touching coil - still no falses, very calm and stabile. But swinging arround few inches over soil surface, sometimes it can bleep??? I still havent find out what should be the reason of that? Several different coils were checked, so i simply can not blame coils for that...Adjusting GEB trimmer slitely mm per mm wont solve problem.Actually GEB trimmer is more likely to affect discrimination than GEB? If rised more you can easilly lose some coloured metals like nickel coins or small silver...GEB trimmer is adjusted at the very point where is just about to lose nickel....
So i was thinking somehow to extend that part of scale. But how?
So i left device aside and tried with coil.That's why nulled latest coil in a bit more "positive" manner...Is it good? I dont know yet. I'll see when rain stops .
I want to ask you is there any other way to extend GEB adjustments on TGS?
Putting multi turn trimm wont solve the problem..

[Max]

mixed silver stuff ?

Hi,
few days ago I've tested my TGS with various coins...on air...and get good results with pure silver but a bit less with alloys.

I've tested with a 30mm diameter 925/1000 silver coin and got 39cm on air... then with another 30mm diameter but 825/1000 silver coin I got much less :
just 34cm on air.

The second coin has probably 165/1000 of copper and I think that influenced much reading about it.

Phase shift due to different metals seems mix in a way that make detection less easy !

I've seen before on other machines similar behaviour... very often with 50% silver coins.

34cm is not too bad for a 30mm coin...but also not a big distance: I'd like to know what do you think about... if you have similar problems e.g. when coinshooting in parks etc

Any comment welcome.

Kind regards,
Max

[Max]

To Ivconic and Max.
I believe that the best way to Null the coils is a oscilloscope . The dummy load must be a resistor and a capacitor parallel with the coil and a resistor in series with coil so the capacitance of the scope probe to don't influence the total capacitance. This is the way that i null my coils
Regards
Btw.. Ivica from who city are you??? Maybe the next month my son to come to Servia for a "Tae Kvodo " fight, i dont know yet the city.....

Hi,
yes I agree. Seems the right way.

Kind regards,
Max

[Max]

The tests were done on UK soil. According to the preamble, it appears that any large iron objects were removed, but small nails, etc., were left in the soil. I suspect the test bed was therefore fairly iron-infested, which is not a good place for testing. However, it surprises me that the Tesoros did not fair well in the test, and these are renowned for their ability to pick out small items amongst the trash. Personally this looks like Minelabs bias at work here. Like all subjective tests it may be unintentional, but who knows? Also, this is very strange, because they are a C-Scope agent.

Hi,
I agree... infested iron soil is not ideal for comparing machines. I think that a clean from iron (totally), medium soil is the best scenario for comparing detectors.

Of course there are some that can deal with trashy sites better than others... but iron is always a problem for any detector and cause conditions can change so radically from site to site... it's better to me having comparision on a clean test-garden.

Then after... some trashy addicted machine could be tested in trashy sites to get a picture of their ability of ignoring iron but still giving useful signals.

I will restrict that last test just for machine claimed of doing that, like some Tesoro's and others claimed trashy addicted MD (e.g. RedHeat).

For example... have not much sense to me a test like above (trashy site) using e.g. a PI detector. It's so easy picking up iron that way that even an essential VLF with no geb could beat the PI in this trash ignoring. Have no meaning for me comparing so different things in that bad/extreme conditions.

Best regards,
Max

[Qiaozhi]

I can agree on this with Geo. From that list i have luck and oportunity to test over 60% of those machines...Not exactly results...I tell you...
Although i can accept differences due type of soils on which test were performed...Might be that test accurate for that type of soil??? Who knows?

The tests were done on UK soil. According to the preamble, it appears that any large iron objects were removed, but small nails, etc., were left in the soil. I suspect the test bed was therefore fairly iron-infested, which is not a good place for testing. However, it surprises me that the Tesoros did not fair well in the test, and these are renowned for their ability to pick out small items amongst the trash. Personally this looks like Minelabs bias at work here. Like all subjective tests it may be unintentional, but who knows? Also, this is very strange, because they are a C-Scope agent.

[ivconic]

Don't believe this test' 7'' for clasicI........ 8'' for XLT, GTI 2500 and 1236???? and 9" for 1266 and X2 and X5 and ........
14'' for Explorer SE (maybe the best detector) and only the half???? for the XLT and GTI2500 (for me are similar with Explorer SE)
I believe that the writer has a sympathy to Minelab

I can agree on this with Geo. From that list i have luck and oportunity to test over 60% of those machines...Not exactly results...I tell you...
Although i can accept differences due type of soils on which test were performed...Might be that test accurate for that type of soil??? Who knows?

[ivconic]

No! Look this one with English translations:

http://www.sokobanja.org.yu/

[ivconic]

Look at this one Geo:

http://www.soko-banja.org/

Regards!

[Geo]

To Ivconic and Max.
I believe that the best way to Null the coils is a oscilloscope . The dummy load must be a resistor and a capacitor parallel with the coil and a resistor in series with coil so the capacitance of the scope probe to don't influence the total capacitance. This is the way that i null my coils
Regards
Btw.. Ivica from who city are you??? Maybe the next month my son to come to Servia for a "Tae Kvodo " fight, i dont know yet the city.....

[Geo]

Hello all

www.staffsmetaldetectors.co.uk/depth_test.htm


Regards
Erol Ünal

Don't believe this test' 7'' for clasicI........ 8'' for XLT, GTI 2500 and 1236???? and 9" for 1266 and X2 and X5 and ........
14'' for Explorer SE (maybe the best detector) and only the half???? for the XLT and GTI2500 (for me are similar with Explorer SE)
I believe that the writer has a sympathy to Minelab

[erolunall]

deep tests results

Hello all

www.staffsmetaldetectors.co.uk/depth_test.htm


Regards
Erol Ünal

[Max]

Dont you think 5.5mV is a way to high?

I am using epoxy also. Yes you are right, it is very slow in drying...Problrm is not in that, problem is in low quality of coil housing. Cheap, recycable plastic has relative movements in time...I noticed that a while ago. That's why insisted on fiberglass housings lately. When dry, no relative movements at all.
Other....
Yes digital multimeters cant measure all signals accuratelly...Capacitor is needed there....but resistor is "sucking" to much of signal to be measured correctly...
Ooops phone is ringing....bye!

Hi Ivconic,
yes 5.5mVpp seems high to me. I get less than 1mVpp on other coils with a bit of patience and slow movements... but I got at first 4.5mVpp then I get now about 5.5mVpp for the DD255x137mm sealed in epoxy.

The good thing is that coil performs very good on depth and detector is now very quiet (so using original LM308N from National... not the bogus ones I posted that are for sure counterfeit parts maybe uA748 relabeled).

I don't know why I get 4.5mVpp at minimum (nulling)... but think that depends on the way overlap on coils is made. Big coil halves mean more critical overlap zones so probably there is the problem on getting less voltage.

I use epoxy and when dry I have no relative movements... but problems could arise during drying of it... the temperature increase could lose temporary fixings and so small out of null are possible... also PVC deformate with heat... that way I think I got another 1mVpp or more respect to unsealed nulled coil.

Anyway... it works fine now, no movements at all... epoxy is like solid rock inside , all around and over the wounds, and so external plastic have a very small impact on performances.

I'd like to use fiberglass housings and at least ABS plastic ones... but so far I cannot order suitable housings from US cause of lacks in communication by the dealer ! So I had to find "something" and then found just PVC stuff of that dimensions.

My original Tesoro's 9x8'' is made of ABS plastic filled with dark epoxy from the bottom... then it has a scuff cover (ABS too I think) to protect the bottom from stones etc
ABS will be good ... also better would be fiberglass or plastic with reinforced carbon sheets... but my problem is where to find them.

Best regards,
Max

[ivconic]

"...If signal is not perfectly a sinus you'll get 0.000V on a digital multimeter very easy... cause they offer good readings only with sinus shaped signals... that's so cause of their internal ADC and circuit configuration... and also at higher frequencies you get still good readings if you have a perfect sinus signal but not on an arbitrary shaped one.

So I think that when you read 0.000v there's actually some magnitude but that your multimeter can't read properly , giving you zero on display.

Adding al foil pieces is like correcting overshots in PI coils with brass washer or similar... actually I think you'll underbalance coil that way... but you know that sometimes you'll gain better sens with a bit out-null config... expecially for non-ferrous items... also your phase shift will somehow balance ground phase shift in medium soils... that way you can use a back GEB setting and maybe detect e.g. silver coin at some depth more.

If you use thin ferrous foil or similar I think you'll need a far GEB setting cause of the added phase shift due to ferromagnetic materials...."




You understood it very well! Couldnt expect less from you. Bravo!
My initial idea was to approach to this on quite unusuall way. I decided to compromise; even to lose iron in favorite to coloured metals..but try to achieve as best as possible response on such items - coloured.
Phase is shifted more than on conventional setups, yes it is true. But response is now better by 10-20%...need to be elaborated further.
Only one thing left more.Fact that some soils consist minerals with same phase shift as "coloured" metals..Havent tested yet on such soils. I guess there will be some problems than!? I'll see.
"...medium soils..." Yes you spelled it right! This kind of setup will perform PERFECT on medium soils. It should be real killer! Yet left to be checked on other type of soils...Who knows, maybe it will turn unusable in those cases?
It is raining these days,damn! I have to wait few days to check it good...
Regards!

[ivconic]

Hi Ivconic,
my last reading on potted coil is about 5.5mVpp that is a bit more than I have when nulled first time. I think that little forces developed due to the epoxy reactions and hardening give me that deviation respect unpotted coil.

I read that with dummy load (1Kohm+15nF) and scope.

One thing to consider is that heat generation due to epoxy... the peak of temperature easy melt or make less heavy fixed the temporary fixings of TX and RX wounds on the housing... BTW my actual housing for this DD255x137 is not the best ...made of PVC plastic that you know is really sensitive to heat and can deformate due to its action.

Anyway, my very slow epoxy (the one for surfboards) revealed a maximum peak of 68 °C (70° C on specs) I've measured before sealing coil... so heat didn't damaged too much my coil null.

Coil sealed have now same performance as it unsealed... and I'm happy of that. Just I have to wait too much for epoxy end-reactions if have to make others. I've also made another DD22 same way.

About multimeters... and nulling, when you null without capacitor I guess you don't get a perfect sinus on RX leads but a disturbed signal (due maybe to e.g. 50Hz intermodulation and similar)...

If signal is not perfectly a sinus you'll get 0.000V on a digital multimeter very easy... cause they offer good readings only with sinus shaped signals... that's so cause of their internal ADC and circuit configuration... and also at higher frequencies you get still good readings if you have a perfect sinus signal but not on an arbitrary shaped one.

So I think that when you read 0.000v there's actually some magnitude but that your multimeter can't read properly , giving you zero on display.

Adding al foil pieces is like correcting overshots in PI coils with brass washer or similar... actually I think you'll underbalance coil that way... but you know that sometimes you'll gain better sens with a bit out-null config... expecially for non-ferrous items... also your phase shift will somehow balance ground phase shift in medium soils... that way you can use a back GEB setting and maybe detect e.g. silver coin at some depth more.

If you use thin ferrous foil or similar I think you'll need a far GEB setting cause of the added phase shift due to ferromagnetic materials.

Best regards,
Max

Dont you think 5.5mV is a way to high?

I am using epoxy also. Yes you are right, it is very slow in drying...Problrm is not in that, problem is in low quality of coil housing. Cheap, recycable plastic has relative movements in time...I noticed that a while ago. That's why insisted on fiberglass housings lately. When dry, no relative movements at all.
Other....
Yes digital multimeters cant measure all signals accuratelly...Capacitor is needed there....but resistor is "sucking" to much of signal to be measured correctly...
Ooops phone is ringing....bye!