TESORO GOLDEN SABRE

[tiktak]

Hi

Yes.
But what for my previous question?

[Max]

BTW where do you buy these housings ?
If you can tell here... otherwise nevermind.

I said that for 1cm coins would be good trying 25cm diameter DD coil... so your housing seems good for that if you want try.

Kind regards,
Max

[Max]

Yes.
But what for my previous question?

Which question ?

[nelson]

Well Max, very good explanation and interesting point to talk about.
My first coil that was tested today, is working at 19.2 Khz, and i can tell you that is finding coins and one silver ring with no problems. Lots of coins, discrimination was set to catch at copper level (btw 1/2 to 3/4 of pot) and almost everything i found today were coins and some aluminium bottles cups. About pulltabs, no problem, the were not detected,geb is working just fine. I can tell you that my TGS is much much betther than ace 250. If i new this befere i ll never got ace 250, a nice machine, but i recognize is it only for beginers. I know now that it can be used has a backup detector, but for more serius searching i for shure get my TGS.
Today i search in a perimeter searshed before with the ace 250 and i got more coins at more deep too.
So i think that TGS can work very good at 19.2 Khz.
I also connect the 22 cms coil, but is working bad, detection for 11 mm coin at only 8 to 12 cms, not good. Sound while detecting not strong and i detect some kind of fading while i pass the coin in front of my coil, so may be i need to reverse leads on rx coil. This coil is well nulling with my tester and also i got good impedance and inductance values.
The coil used today with results posted here, is 22 cms diameter, 4.6 mH RX and 3.8 mH TX, resistance 21.8 and 21.4 ohms.

More about my test later.

Thanks and best regards Max

Nelson

Hi Nelson,
remember now I have to answer your question !

" mean, if i set up the detector for 14 Khz i know i m on the correct performance, but if for example change the frequency to run it at 20 khz, will performance by reduced or not?"

Very good question.

If you run it out-frequency you could gain or lose.
Lets explain.
If you use e.g. a too lower frequency you'll have surely problems.
Example : TX f = 5Khz
your voltage converter run at f/2 = 2.5KHz

No way. You'll lose all your negative rail voltage that way. f too low.

Example : f=10Khz
Could work fine. BandidoII runs at 10KHz...
problem is always related to voltage converter output... but I think you'll get something from -2V to -2.5V that way and maybe changing some IC for less wasting current devices (e.g. TLC2262, MC33178 and the like).
Could work, you'll have maybe less performance cause of less voltage on coil... but could work even good.

Much better I think at 12KHz or 12.5Khz... very good freq. here. (have to try ).

Now more f
Example : 20Khz... uhm
You don't have problems on voltage converter that way (runs at 10Khz) BUT... 20Khz on the TX coil... uhm far above expected frequency e.g. for preamp up... maybe is better using the 5pF cap that time on LF353.

But it could work.

The big question is why changing freq ???

ANSWER ARE: SKIN EFFECT AND SMALL TARGETS

Higher frequencies are good for small items detection... cause even small things develop much eddy currents at higher frequencies... BUT there is a BIG (or depends... could be ENORMOUS) problem... FOIL.

FOIL IS ADDICTED TO HIGHER FREQS... also your shield would develop much more eddy currents at higher freqs... but that's not the real problem... I think that here isn't worth using e.g. 20KHz at tx osc... pay now or pay later on the search field...

But if you have clear and "easy soil" searchfield... why not.
Some soils are less easy at higher freqs... I know very well.

You have to consider also that GSabre parts are designed to run at that 14Khz ...of course can work at other freqs... but you can pay somewhere in the circuit if don't mod. some bit parts. Critical parts are preamp, sampler/integrators and voltage converter.

I think that good range to try freq. mods is 14KHz +/- 2.5Khz

Best regards,
Max

[nakky]

TO TIK TAK

HI,
MAX.
Its look like I haven't understand you buy former I mean the thing that I wind the windings on and according to your last post you mean coil housing???
Please make this clear too.
I now that its stupid but I wanna be well prepared.And make no or minimum mistakes!
Thanks

TIK TAK what do you think? NO MISTAKES,this is not all I made,your not there! Grt Nakky

[tiktak]

To nakky

What?

[nelson]

Today i measure inductance of my first 22 cms coil, with a professional inductance meter and this shows the following:

TX 6.025 mH RX 7.010 mH

With a multimiter

TX 3.8 RX 4.6 mH

Problem is that 3.8 and 4.6 values are ok for good deep, but out of range and also frequency is 19.2 Khz, not 14.Khz. But if you consider that values taken wit the pro inductance, this are fine to.
So if i measure my second coil, that by now is not working good, this shows:

With pro inductance meter

TX 8.6 mH RX 9.1 mH

With multimiter

TX 5.9 mH RX 6.4 mH

This is very confising, cause if you see, the second coil fits a frequency of 13.8 Khz, very close to the original but not working good and the good coil that is running at 19.2 Khz, works very good.

What do you think?

Regards

Nelson

Well Max, very good explanation and interesting point to talk about.
My first coil that was tested today, is working at 19.2 Khz, and i can tell you that is finding coins and one silver ring with no problems. Lots of coins, discrimination was set to catch at copper level (btw 1/2 to 3/4 of pot) and almost everything i found today were coins and some aluminium bottles cups. About pulltabs, no problem, the were not detected,geb is working just fine. I can tell you that my TGS is much much betther than ace 250. If i new this befere i ll never got ace 250, a nice machine, but i recognize is it only for beginers. I know now that it can be used has a backup detector, but for more serius searching i for shure get my TGS.
Today i search in a perimeter searshed before with the ace 250 and i got more coins at more deep too.
So i think that TGS can work very good at 19.2 Khz.
I also connect the 22 cms coil, but is working bad, detection for 11 mm coin at only 8 to 12 cms, not good. Sound while detecting not strong and i detect some kind of fading while i pass the coin in front of my coil, so may be i need to reverse leads on rx coil. This coil is well nulling with my tester and also i got good impedance and inductance values.
The coil used today with results posted here, is 22 cms diameter, 4.6 mH RX and 3.8 mH TX, resistance 21.8 and 21.4 ohms.

More about my test later.

Thanks and best regards Max

Nelson

[tiktak]

hi

Hi,
Max.
This question:
Hi,
Max.
Thanks again!My mistake!

But can you tell me what is this 9X8 and 12X10 in cm-s?
Are they DD?

I will use 0,25 without the varnish!

Which is yours 22 DD?

Look at this DD11 why RX have less inductance and resistance from TX?
Shouldn't they be reverced?This DD 11 in inch must mean 27cm?/1 inch=2,5cm/

And I buy housing from a friend!And if you wanna I will send you a couple buy the post!I own you much,so no problem.
Just send me e-mail with your addres.I have payed 2,5 euro for this one!There are 32 and 38!But I now that you are interested in this 28 !Right!
I wanna make this 25 but still dont now how much turns???
Cant find cheep and good multimeter all are expensive!
So if you tell me how much turns I will be able to make good coil with what I have!
Thanks

[nakky]

To Tik Tak

What?

You are still not there,you have a long way to go Experiment.Grt Nakky.

[tiktak]

What do you mean.I now man learn until he die!
But in what order of toughts you tall this?
Did you point me a mistake or what?

[tiktak]

hi

Hi,
Max.
Excuse me I have make a frustration here.
The 28cm coil housing someone measure outer diameter not the winding that can be put in!The space if for 25cm in inner diameter/former size/ ,and 27 the outher diameter.

[nakky]

ToTik Tak

What do you mean.I now man learn until he die!
But in what order of toughts you tall this?
Did you point me a mistake or what?

What I will say,we all make mistakes,thats not bad,we can learn from it.Grt Nakky.

[Max]

Today i measure inductance of my first 22 cms coil, with a professional inductance meter and this shows the following:

TX 6.025 mH RX 7.010 mH

With a multimiter

TX 3.8 RX 4.6 mH

Problem is that 3.8 and 4.6 values are ok for good deep, but out of range and also frequency is 19.2 Khz, not 14.Khz. But if you consider that values taken wit the pro inductance, this are fine to.
So if i measure my second coil, that by now is not working good, this shows:

With pro inductance meter

TX 8.6 mH RX 9.1 mH

With multimiter

TX 5.9 mH RX 6.4 mH

This is very confising, cause if you see, the second coil fits a frequency of 13.8 Khz, very close to the original but not working good and the good coil that is running at 19.2 Khz, works very good.

What do you think?

Regards

Nelson

Hi,
I think that if you get 13.8KHz your multimeter maybe measure inductance better than the professional inductance meter.

TX 5.9 mH

Is what I expect for frequency of 13.8KHz in Gsabre oscillator.

I think that your problem with this coil is not in inductance that seems about the same of chart and the same I have... but in the nulling.

I think your second coil isn't nulled well as first one... or that you have reversed leads respect to the right way.

Check the null... then test, swap rx leads, and test again.

Best regards,
Max

[Max]

Hi,
Max.
Excuse me I have make a frustration here.
The 28cm coil housing someone measure outer diameter not the winding that can be put in!The space if for 25cm in inner diameter/former size/ ,and 27 the outher diameter.

Hi tiktak,
don't worry... no problems.
Thanks for the kindly offer about housings, I have some spare too here... was just curiosity.

I've tryed to get some from one dealer some time ago but I cannot get them cause the dealer sleeps hard on the keyboard I think... anyway.

25cm I mean external diameter of the whole DD coil. It's total circumference.

I think a good number of turns is around 110 for it... calculation is not easy... you have to wound a bit more turns... then cut some away to get right inductance and so frequency on tx oscillator (14Khz).
Then add say 10turns to the rx coil... that's all.


Best regards,
Max

[tiktak]

Hi,

Hi,
Max.
I mean 25cm diameter for former in D shape!Not O 25 cm!
I read somewhere that its no good to change form.Its better to use former with right shape and wind directly/like IVCONIC/.
And I found my mistake/its not my,but...../
I have mesured my old wire and WOW 0,32 without the varnish!!!
You have told me that even 0,30 is no good whats up for 0,32!!!!
But the truth is that the coil is good!!/good in air I am shore that in soil will have bad performance as you say!/
Why it perform well?
But now I have 0,25 and will wind your 22cmDD coil.Because I am not shore how much turns for this NEW coil?
I remember your advice but ..... still dont have good multimeter to chech frequency and inductance!
For your 22DD and Ivconics 28DD I think will be more easy because I now how much turns.So thats why I ask you so many times.

If I can help for housing or something else just tell me
Thanks