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**ivconic** · 03-19-2008, 10:52 PM

This suppose to be local thing, my amateur try...
Everybody welcome...if understand Serbian..
...

**ivconic** · 03-19-2008, 11:04 PM

Regards!

**tiktak** · 03-21-2008, 12:28 PM

Hi

Hello,
Ivconic.
I just went for new wire and found out why I have differances.Now I measuere the wire my self and its shows 0,246 bare.
Is this posible.
But the most important thing is that my previous wire is thiner than this.The probleme is that I were shore/no doubt 0,25 bare/but its thiner!So now I will wind again all the coils with this.Its not much 0,600gr but its enough for now.
Why you and Max dont Help on TGS ADVANCED?I am almost ready but now I wont be able to post for a while.
See you soon.
p.s.did you made sucsesfull larger omega coil?I have noticed that my 21cm omega is sensitive to ferite rod but its not shielded and nulled!
Ivconic I saw somewhere coil that is O rx and two DD th inside that!Have you tryed such configuration?

**tiktak** · 03-21-2008, 12:34 PM

hi.

O
And one more thing nice work with your site!

**Max** · 03-21-2008, 01:50 PM

Originally posted by tiktak View Post

Hello,
Ivconic.
I just went for new wire and found out why I have differances.Now I measuere the wire my self and its shows 0,246 bare.
Is this posible.
But the most important thing is that my previous wire is thiner than this.The probleme is that I were shore/no doubt 0,25 bare/but its thiner!So now I will wind again all the coils with this.Its not much 0,600gr but its enough for now.
Why you and Max dont Help on TGS ADVANCED?I am almost ready but now I wont be able to post for a while.
See you soon.
p.s.did you made sucsesfull larger omega coil?I have noticed that my 21cm omega is sensitive to ferite rod but its not shielded and nulled!
Ivconic I saw somewhere coil that is O rx and two DD th inside that!Have you tryed such configuration?

Hi,
TGS ADVANCED ? You mean the modified Czech sabre ?

Well I'm doing other stuff (mostly digital) at now... hae not much free time to test also this design for now.

I will take a look there... but I think this thread will be better moved on the tech forum here if you wanna discuss about tuning etc.

Kind regards,
Max

**tiktak** · 03-22-2008, 01:34 PM

Hi

Hi,
Max.
Thanks.But no need for now!
What digital did you make?

**Max** · 03-22-2008, 04:01 PM

Originally posted by tiktak View Post

Hi,
Max.
Thanks.But no need for now!
What digital did you make?

Hi,
not metal detector... digital I mean is a driver for some graphic LCD displays... I cannot find on the Internet to add to my PICs !

So I programmed a bit using assembly stuff.

I bought some data vision displays without checking before the datasheet...

and so... you know...

if I wanna use them I need this code!

Kind regards,
Max

**erolunall** · 03-22-2008, 09:47 PM

Hello Max

How r u. You did not answer my question by mail.
about computer frequency generator
is it foolish or unpossible?

Regards
Erol

**Max** · 03-23-2008, 07:01 PM

Originally posted by erolunall View Post

Hello Max

How r u. You did not answer my question by mail.
about computer frequency generator
is it foolish or unpossible?

Regards
Erol

Hi Erol,
sorry... I check that email address just from time to time.

ok... the answer is : yes we can (this is not any promotional political message)

Yes sure, we can cause if you wire up some pins at your e.g. parallel port
you can send pulses controlling them by software.

I't easy to made in C, C++, Delphi etc etc etc also Assembly code (to be exact you will use assembly for some fast routines stuff).

It's not only possible but widely used in many applications like timing of data loggers and similar.

Problem is accurancy: you need your software runs with very high priority on the host system (like a laptop PC for example) so running very close to priority of operating system.

Why ? Simple your timing depends on software... and if your software is delayed by operating system you have jitters... so frequency variations.

It's easy putting an e.g. level shifter on the serial port too (e.g. MAX232 or MAX3232 etc) and converting the RS-232 levels of voltage to e.g. TTL levels (0-5V) and then gate a mosfet etc.

This way you can e.g. implement a complete PI detector using a laptop... you will use e.g. the soundcard inputs for reading analog values from op amps on your external PI pcb.

The question is if it's worth or not doing this way instead of having e.g. a microcontroller running in a metal detector... or doing it discrete way... with monostables etc.

The answer is that PC approach is more flexible... and if you use special, fast stuff (like ultra fast ADC) you can do many samplings ... many many more I mean than a conventional PI... for example... SO YOU GAIN INFORMATION DETAILS.

These details could be used for e.g. trying to disc stuff in PI detector.

There was the Hoolko's thread about digital VLFs that is a similar approach to VLF (doing digital way) you can implement too by computer.

Problems are related to dedicated and fast hardware required for sampling signals... sure not to programs. Maybe the good solution is assembly the detector using existent ultra fast datalogger hardware 8the kind used e.g. in medical imaging... why not... if you can find portable etc)

Sure it's complex project both if PI or VLF stuff... or ibrid design... always hard about software (for unskilled people I mean)... and much more harder about hardware required for good results.

Hope this was exaustive answer.

Forget about LRL... these are unsafe things... at least till one will give reliable proofs they could be really implemented as true working stuff respect to claims.

Kind regards,
Max

**Fred** · 03-25-2008, 03:09 PM

Hi Ivconic,
I have been experimenting with a cc coil for the TGS: i used 20cm TX, 107 turns gives 6mH , 0.25mm teflon islolated silver plated wire.
For RX around 160 turns 12cm same wire to give 6.5mH.
Then bucking coil was 36 turns around Rx coil, wich gave an excellent nulling.
Behaviour of the coil was very good too,disc, ground, EXCEPT RANGE , wich was quite bad.
My conclusion is that the bucking coil modifies too much the total inductance of both coils, it is too dificult to correctly tune them.
The bucking coil make the total inductance of the TX one go to 5.1 mH, but to increase nº of turns we should also modify the bucking nº of turns, wich in turn changes again inductances.A hell.
Have you been more succesfull with the omega ?
I would like to build a better one, around 22cm diameter.
Regards,
Fred.

**Aziz** · 03-25-2008, 04:20 PM

Originally posted by Fred View Post

Hi Ivconic,
I have been experimenting with a cc coil for the TGS: i used 20cm TX, 107 turns gives 6mH , 0.25mm teflon islolated silver plated wire.
For RX around 160 turns 12cm same wire to give 6.5mH.
Then bucking coil was 36 turns around Rx coil, wich gave an excellent nulling.
Behaviour of the coil was very good too,disc, ground, EXCEPT RANGE , wich was quite bad.
My conclusion is that the bucking coil modifies too much the total inductance of both coils, it is too dificult to correctly tune them.
The bucking coil make the total inductance of the TX one go to 5.1 mH, but to increase nº of turns we should also modify the bucking nº of turns, wich in turn changes again inductances.A hell.
Have you been more succesfull with the omega ?
I would like to build a better one, around 22cm diameter.
Regards,
Fred.

Hi Fred,

which inductive calculator do you use?
I found this site: http://emclab.mst.edu/inductance/circular.html
Which radius of the windings do you have? I mean not the wire diameter but the total 107 windings diameter (not 20 cm).

**Fred** · 03-25-2008, 05:02 PM

Originally posted by Aziz View Post

Hi Fred,

which inductive calculator do you use?
I found this site: http://emclab.mst.edu/inductance/circular.html
Which radius of the windings do you have? I mean not the wire diameter but the total 107 windings diameter (not 20 cm).

Hi Aziz,
No calculator: I wound more turns, then take out untill i get right inductance.

Of course inductance increase when you tight up te wires with tape, but with some experience it´s OK.For example 5.8mh when thightened will give around 6 ...
Radius is 10cm for TX coil (20cm diameter),6cm for RX.
Regards,
Fred.

BTW, how do you know mu :
m(relative) = m(material) / m(air)
where: m(air) = 1.256 x 10-6 H/m
What is mu of material?

**Aziz** · 03-25-2008, 05:19 PM

Originally posted by Fred View Post

Hi Aziz,
No calculator: I wound more turns, then take out untill i get right inductance.

Of course inductance increase when you tight up te wires with tape, but with some experience it´s OK.For example 5.8mh when thightened will give around 6 ...
Radius is 10cm for TX coil (20cm diameter),6cm for RX.
Regards,
Fred.

BTW, how do you know mu :
m(relative) = m(material) / m(air)
where: m(air) = 1.256 x 10-6 H/m
What is mu of material?

Hi Fred,

thanks for quick reply.

µr (relative permeability) is 1.0 for air. Just enter 1.0 in the web site mentioned above. µ = µ0 * µr, µ0 = 4*PI*10^-7 (=absolute permeability). µ is used for the Magnetic Flux Density (B-Field) calculation from Magnetic Field Strength (H-Field). B = µ*H = µ0*µr*H.

I am a little bit confused about the parameter a. Mean this the wire radius or the bunch of the stranded wires radius. I don't know yet.
If anyone has a better online/offline inductivitiy calculator, please let me know.

I have to check the algorithms for inductivity and induction calculations.
Regards,
Aziz

**ivconic** · 03-25-2008, 08:07 PM

Originally posted by Fred View Post

Hi Ivconic,
I have been experimenting with a cc coil for the TGS: i used 20cm TX, 107 turns gives 6mH , 0.25mm teflon islolated silver plated wire.
For RX around 160 turns 12cm same wire to give 6.5mH.
Then bucking coil was 36 turns around Rx coil, wich gave an excellent nulling.
Behaviour of the coil was very good too,disc, ground, EXCEPT RANGE , wich was quite bad.
My conclusion is that the bucking coil modifies too much the total inductance of both coils, it is too dificult to correctly tune them.
The bucking coil make the total inductance of the TX one go to 5.1 mH, but to increase nº of turns we should also modify the bucking nº of turns, wich in turn changes again inductances.A hell.
Have you been more succesfull with the omega ?
I would like to build a better one, around 22cm diameter.
Regards,
Fred.

Make approx. 90 turns for TX and continue with f.b. in oposite direction untill adjust to good null.
C.C. coils...hmmm!? I died making simillar for Classic III, at the time.
Good null...substract 2-3 windings from F.B. at the end and use those as nulling loop, randomly placing it inside coil housing and monitoring induced voltage at RX, to fine redjust balance. Would be good to monitor phase behavior also.
Regards!

**Fred** · 03-25-2008, 09:56 PM

Originally posted by ivconic View Post

Make approx. 90 turns for TX and continue with f.b. in oposite direction untill adjust to good null.
C.C. coils...hmmm!? I died making simillar for Classic III, at the time.
Good null...substract 2-3 windings from F.B. at the end and use those as nulling loop, randomly placing it inside coil housing and monitoring induced voltage at RX, to fine redjust balance. Would be good to monitor phase behavior also.
Regards!

Ok Ivconic, thanks ,
You died making them?

But what about detection distance? i don´t like very much the beahaviour of the DD, really omega and CC seem to be more reliable in several aspects, so i would like to try a good one of those.
As i said, for CC i was able to achieve a good null, but inductance was bad, so was the frequency,because of influence of bucking coil.This would not be so bad with omega i think.
regards,
Fred.

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