TESORO GOLDEN SABRE

[tiktak]

Hi,

Hi,
Fred do not encurige wild desert or what ever..
This is TGS tread!!!!
There is sabre digital already which is multichanel and......
We already have 105 PAGES its more than confusing to find something and a lot of frustration apears.

[Qiaozhi]

Digital TGSL

I've copied everything on this subject to a new thread - Digital TGSL.
Wild_Desert - please post there, if you wish to discuss a digital version of the TGSL.

[ivconic]

You must understand my persistence on this;
recently i tried to find some posts here on this huge thread - without success!
To many off topics here! To many!
So i spend 2 hours listing and reading all over again to finally find what i looked for!
Sheeeeesh!!!

P.S.
"serach" didnt helped - to many repeatable terms in almost every post!!!

[Fred]

You must understand my persistence on this;
recently i tried to find some posts here on this huge thread - without success!
To many off topics here! To many!
So i spend 2 hours listing and reading all over again to finally find what i looked for!
Sheeeeesh!!!

P.S.
"serach" didnt helped - to many repeatable terms in almost every post!!!

Hi Ivconic,
I know what you mean : i have done this too before, you probably remember my posts refering to already known questions that were getting on your nerves .
It would be great to make a new thread with only posts containing technical information (and not questions).But thats´s a huge job..
regards,
Fred

[ambassador]

TESORO GOLDEN SABRE

You must understand my persistence on this;
recently i tried to find some posts here on this huge thread - without success!
To many off topics here! To many!
So i spend 2 hours listing and reading all over again to finally find what i looked for!
Sheeeeesh!!!

P.S.
"serach" didnt helped - to many repeatable terms in almost every post!!!

IVCONIC and others are Correct . Yes OFF TOPIC is a problem when people do not follow the rules or do not understand the rules printed in english language , or some Members have had too much to DRINK and type a post just to start an argument . CARL or a Forum Member he trusts needs to monitor the posts everyday and make corrections immediately . NO EXCEPTIONS !!!!

[Max]

Hi,
the discussion was about a digital version of TGSL... so not totally off topic.

But the thread is already too large... so we need to stay on topic... and create new threads for revisions or modifications of original design.

Kind regards,
Max

[Max]

new (gigantic ?) 12'' coil for TGS

Hi all,
I've made a new one...for teh collection... this is a 12''DD for TGS, as well as other uMax models, can use too.

Here's actual recipe:

wire 0.25mm bare (30AWG)
TX turns = 88
RX turns = 92

TX resistance is about 24ohm
RX resistance is around 25ohm

TX L = (about) 5.7mH
RX L = (about) 6.15mH

For those who need MUCH depth...

Can get a coin at 50cm (half-crown)!

1eur at 42-43cm , in disc mode.

Bigger stuff at incredible depth....like a small round copper thing (6cm diameter) at 65cm !

Do you think this will win the cache test challenge now hands down?

I don't care much... personally I don't like large coils over 27-28cm diameter but made this to check how much TGS can be pushed with 30cm... and it can be pushed to work in the 50cm range on big coins. (at least on air)

I've tested with a small container and 5 silver coins of about 2 cm inside... and it detects the container (plastic stuff) easy at 60cm on the air.

Disc seems works right way, iron about ignored if soft... steel detected sometimes (like other coils , also originals).

Ferrite is nulled well and works good on normal soil, not tested yet on hard soil... mineralized stuff.

All measures made on air.
Anyway... here it is... who like big stuff can try it.
Inner diameter of DD is exactly 30cm, so 12''.

DISCLAIMER:
Tuning is critical cause of sharp phase shift requirement to get good depth on silver and mantaining iron disc, but can be done with lot of efforts and patience...for this is similar to other homemades that require also similar trial and error process... using test targets to check at each small movement. Just this is more sensitive... and require enormous care on that.

So before attempting making one... ask yourself if you're brave enough! You can have lot of troubles trying to replicate it... I've told you.

MADE AT YOUR OWN RISK...and please no questions...I've already gave its recipe.

BWT, I think it will bust any original 10x12'' or widescan from Tesoro... but I haven't so cannot compare. Just my experience with originals say me that...

Enjoy!

Kind regards,
Max

[Fred]

Nice work Max!
Nice coil collection for TGS
regards,
Fred

[miki73]

Max plese can you explain me bit more ``with phase required (around 200°) between tx and rx signals``

How measure and adjust phase?And if i dond ask too much some picture of that tunning..

And please what is center tapering? Coil wouded with alu foil and conect to ground or?

Regards too all!

[Max]

Max plese can you explain me bit more ``with phase required (around 200°) between tx and rx signals``

How measure and adjust phase?And if i dond ask too much some picture of that tunning..

And please what is center tapering? Coil wouded with alu foil and conect to ground or?

Regards too all!

Hi,
the phase is relative to Tx signal: you do this way...
connect channel one of scope to TX oscillator, ground to ground and probe to collector of transistor.

Then you connect channel two: ground to ground... probe to pin7 of preamp (LF353).

Then you trigger the scope using channel one.

OK... then you'll see that phase shift on the screen... adjust amplitude/timebase of both channels if required.

You'll look for rx phase it must be in the 200° range in tesoro coils... at least... both the two I have tested have that similar phase.

If it isn't you'll play with nulling... trying to get a good null but that phase shift too. Sometimes, I say you, it's impossible... you scrap the coil and made another... no easy solution to that till now.

It's easy... I think Qiaozhi posted a picture with both TX and RX signals from a CC coil from tesoro... but you don't need it... just that measuring phase of RX you'll get around 200°. Sometimes I saw it not critic... even with 185° works too (not as best... but works)... other times, like in these larger coils you need be more accurate...

When you have a good nulling and correct phase shift... your coil is ready to go.

I don't use center tap in these coils at now; maybe in future homemade I do that way too.

You can use foil...why not ? it's cheap and easy stuff... just avoid putting too much, overlap as few as possible.

Kind regards,
Max

[Max]

just to have an idea... (only for this time)

blue is like tx
yellow is like rx

you should see something similar...on the scope.

[miki73]

This is phase diference about 200° ?

Max you are the best man!Make me happy!

[Max]

This is phase diference about 200° ?

Max you are the best man!Make me happy!

Hi,
yes it is... are 200° for RX... cause the positive edge is delayed 200° from reference (TX).

Kind regards,
Max

[simonbaker]

Hi all,
I've made a new one...for teh collection... this is a 12''DD for TGS, as well as other uMax models, can use too.

Here's actual recipe:

wire 0.25mm bare (30AWG)
TX turns = 88
RX turns = 92

TX resistance is about 24ohm
RX resistance is around 25ohm

TX L = (about) 5.7mH
RX L = (about) 6.15mH

For those who need MUCH depth...

Can get a coin at 50cm (half-crown)!

1eur at 42-43cm , in disc mode.

Bigger stuff at incredible depth....like a small round copper thing (6cm diameter) at 65cm !

Do you think this will win the cache test challenge now hands down?

I don't care much... personally I don't like large coils over 27-28cm diameter but made this to check how much TGS can be pushed with 30cm... and it can be pushed to work in the 50cm range on big coins. (at least on air)

I've tested with a small container and 5 silver coins of about 2 cm inside... and it detects the container (plastic stuff) easy at 60cm on the air.

Disc seems works right way, iron about ignored if soft... steel detected sometimes (like other coils , also originals).

Ferrite is nulled well and works good on normal soil, not tested yet on hard soil... mineralized stuff.

All measures made on air.
Anyway... here it is... who like big stuff can try it.
Inner diameter of DD is exactly 30cm, so 12''.

DISCLAIMER:
Tuning is critical cause of sharp phase shift requirement to get good depth on silver and mantaining iron disc, but can be done with lot of efforts and patience...for this is similar to other homemades that require also similar trial and error process... using test targets to check at each small movement. Just this is more sensitive... and require enormous care on that.

So before attempting making one... ask yourself if you're brave enough! You can have lot of troubles trying to replicate it... I've told you.

MADE AT YOUR OWN RISK...and please no questions...I've already gave its recipe.

BWT, I think it will bust any original 10x12'' or widescan from Tesoro... but I haven't so cannot compare. Just my experience with originals say me that...

Enjoy!

Kind regards,
Max

Pure artwork!

[simonbaker]

Hi,
I've downloaded LTspice and using some parts of files from porkluvr I'm doing some training on the simulator... just to see how to move around menus.

I'm happy of results cause I find it really intuitive and easy to use...but that's my impression... you could contestate!

Anyway, I've simulated the original (about) TGS osc with a 4.7 zener diode and 8V supply....

then I've changed the params... using a 15v zener diode (BXZ84C15L) to see the jump at output voltage.

As you can see with that +18v supply and 15v zener it gives about 30Vpp instead of original about 10Vpp: 3 times.

No other mods seem required e.g. for PN2222 that drives the 4024... but , of course, one have to put a stable +18v supply for osc section only (few mA current required)...even 2x9volts batteries could be good for tests.

So maybe people that want experiment with osc signal amplitude can do that way... well signal is not a perfect sinus on sim but I think could be ok for some raw tests.

I think that there's no need of that change on TGS... cause I found really good as is... but if someone would like to try... and inform us of results e.g. in air will be cool!

I can't do cause I have to dismantle the thing from housing and it's now hard work.

Best regards,
Max

I tried similar variations of TGS oscillator with LTSpice. Results:

 
JFet Vcutoff      Zener          Vcoil P-P
------------      -----          ---------
-.5 V              4v3             -3.5 to 3.5 
-.5 V              6v0             -5.2 to 5.2
 
-2.75 V            4v3            -6.4/-6.9 to 6.5/6.7 (instability)
 
-5.0 V             4v3            -7.7 to 7.4
-5.0 V             6v0            -7.7 to 7.4

Conclusion: coil voltage is sensitive to JFet cutoff voltage and Zener breakdown voltage. If JFet breakdown is small (-.5), can be corrected somewhat by increasing zener breakdown. If JFet breakdown is big, zener not affect - maybe lose gain control.

With JFet cutoff of -2.75, LTSpice showed significant instability, peak voltages changing. Other cases may have had smaller instability too.

The instability shown by LTSpice was very fast, every other cycle. But slower limit cycles very possible in real life.

Maybe instability not important because lock-in amp is synchronized.

JFet cutoff is important because it affects the voltage of your coil oscillation. Variations in J107 cutoff voltage would make production models of TGS have different depth. What did Tesoro do about that? Test each J107?

-SB