TESORO GOLDEN SABRE

[Qiaozhi]

Sory Qiaozhi, yelow brother, I didn't mean to hurt you. The multimeter is good, even isn't from China - joke of course. Your coil calculator seems better for this coil. I reduced turns from 117 to 98, inductance is 6.65 mH think it is good enough for rx coil, freq rise at 13.6 kHz. Now winding tx coil, suppose about 95 windings to get 6 mH, then shielding, nulling, when finish I'll post report. But that sound... appearing when connect tx coil and disappear when disconnect coil. Never mind, when connect rx coil, will try again.
Wish you all the best.

Good to hear you are making progress. Please let us know when you have success.

[Hush]

Sory Qiaozhi, yelow brother, I didn't mean to hurt you. The multimeter is good, even isn't from China - joke of course. Your coil calculator seems better for this coil. I reduced turns from 117 to 98, inductance is 6.65 mH think it is good enough for rx coil, freq rise at 13.6 kHz. Now winding tx coil, suppose about 95 windings to get 6 mH, then shielding, nulling, when finish I'll post report. But that sound... appearing when connect tx coil and disappear when disconnect coil. Never mind, when connect rx coil, will try again.
Wish you all the best.

[nelson]

Ok thanks Max.

In my case i obtened 4-5 cms more, just by adding a 15 nF cap btw the two rx leads just beside the coil. I had not made any changes on the pcb, so i think this will be the rigth way to get the best sens from the coil.
About frequency i miss that, it is 14 Khz, sorry.

Regards

Nelson

Hi Nelson,
13KHz is lower than original (14KHz) but if it works ok no problems.
I always test adding or sub about 500pF at a time found often that increase or decrease of few nF (4-5nF maximum) get me on the right way to get max sens from coil.

So you could test from 10nF to 20nF on GS.

I've done in bandidoII, got about 1-2 cm gain respect original value.

Few depth more, of course, but if a simple cap mod could give that, it's good.

At now have no time to test same thing on GSabre but I'll do soon.

Kind regards,
Max

[Max]

Hi,
Max.
Yes you are right its reversed!
I will try.
By the way I found my mistake.I were using 0,30 without varnish!And have make 165 turns for both coils on 19cm former!
This is too much!
In the original coil wire is 0,25 without the varnish right?
I have order small quantity of 0,25 wite without the varnish,so how many turns I have to wind on 19 cm former to make proper DD coil.And how much is this distance?I now that picture is not good and the part forming overlap area should be wider.But you understand what I ask.
Thanks

Hi tiktak,
yes 0.25 without varnish (that is some 30AWG) or also bit more is good too.
0.30 without varnish gave me same results when I changed caps but it's too tricky to be done, I think, getting right resistance and inductance required at first sight. I wasted much wire of this kind before getting right things.
Can't remember now the exact distance but think was something 12.5 or 12.7cm in the middle.

Best regards,
Max

[Max]

HI MAX.

A QUESTION, IS CORRECT TO TUNE YOUR RX COIL TO GET MAXIMUN SENSITIVITY BY TRYING A FEW CAPS ON THE RX COIL BTW BOTH LEADS AND WHAT ARE CORRECT VALUES TO TRY?

YESTERDAY I PLAYED WITH SOME CAPS VALUES AND I NOTICE THAT SENSITIVITY WAS AFECTED TO BE WORSE AND BETHER TOO.

MY TRANSMIT FREQUENCY IS 13 KHZ.

FOR MY COIL HOUSING I USED A PICE OF POLITYNE, DRAW THE COILS FORM ON IT, BURN WITH MY IRON THE FORM TO MAKE A FORM SPACE TO PLACE MY COIL AND AFTED THAT I USED POLITYNE FOAM TO SEAL IT. THE RESULT, A SOLID AND SEALED COIL THAT IF YOU WANT CAN BE PLACED ON A PLANTS PLASTIC BASE OR ALONE. SO WHEN I HAVE THE TIME I LL TAKE PICTURES OF WHAT I HAVE DONE TO LET THE FORUM KNOW.

BEST REGARDS

NELSON

Hi Nelson,
13KHz is lower than original (14KHz) but if it works ok no problems.
I always test adding or sub about 500pF at a time found often that increase or decrease of few nF (4-5nF maximum) get me on the right way to get max sens from coil.

So you could test from 10nF to 20nF on GS.

I've done in bandidoII, got about 1-2 cm gain respect original value.

Few depth more, of course, but if a simple cap mod could give that, it's good.

At now have no time to test same thing on GSabre but I'll do soon.

Kind regards,
Max

[nelson]

HI MAX.

A QUESTION, IS CORRECT TO TUNE YOUR RX COIL TO GET MAXIMUN SENSITIVITY BY TRYING A FEW CAPS ON THE RX COIL BTW BOTH LEADS AND WHAT ARE CORRECT VALUES TO TRY?

YESTERDAY I PLAYED WITH SOME CAPS VALUES AND I NOTICE THAT SENSITIVITY WAS AFECTED TO BE WORSE AND BETHER TOO.

MY TRANSMIT FREQUENCY IS 13 KHZ.

FOR MY COIL HOUSING I USED A PICE OF POLITYNE, DRAW THE COILS FORM ON IT, BURN WITH MY IRON THE FORM TO MAKE A FORM SPACE TO PLACE MY COIL AND AFTED THAT I USED POLITYNE FOAM TO SEAL IT. THE RESULT, A SOLID AND SEALED COIL THAT IF YOU WANT CAN BE PLACED ON A PLANTS PLASTIC BASE OR ALONE. SO WHEN I HAVE THE TIME I LL TAKE PICTURES OF WHAT I HAVE DONE TO LET THE FORUM KNOW.

BEST REGARDS

NELSON

Hi,
too low frequency. You have to match 14KHz on tx coil...
first 3-4 seconds battery checker makes ear you a steady tone.... then detector fade to no sound at all.
If not so there is something wrong.

Recheck coil calculation and measures.

Best regards,
Max

[tiktak]

hi

Hi,
Max.
Yes you are right its reversed!
I will try.
By the way I found my mistake.I were using 0,30 without varnish!And have make 165 turns for both coils on 19cm former!
This is too much!
In the original coil wire is 0,25 without the varnish right?
I have order small quantity of 0,25 wite without the varnish,so how many turns I have to wind on 19 cm former to make proper DD coil.And how much is this distance?I now that picture is not good and the part forming overlap area should be wider.But you understand what I ask.
Thanks

[Max]

Hi ApBerg, thank you for replay!
As you wrote, I've connected coil on transmitter and frequency was 11.7 kHz
Then connected cap 15nF parallel with coil, like you suggest, freq drop at
8.9 kHz.All the time I heard constant tone in head phone, is it normal? When connected cap, tone was lower.
About coil: that should be double O coil like Ivconic's. Nexus made similar.
To Geo: very good idea,maybe try it later. Now seems my multimeter was right! I' try to reduce number of turns.
ApBerg,Geo,man from Mars thanks a lot!
Salute you!

Hi,
too low frequency. You have to match 14KHz on tx coil...
first 3-4 seconds battery checker makes ear you a steady tone.... then detector fade to no sound at all.
If not so there is something wrong.

Recheck coil calculation and measures.

Best regards,
Max

[Max]

Hi,
Max.
Is this what you talking about?But what is this diode?
1N4148?

Hi,
your diode is reversed respect to schematic.
Use 1N4007.

Kind regards,
Max

[Qiaozhi]

Ohhh..
I am in big trouble!
I spend all bloody day to wind coil, wind by wind, without any crossing of wires.I've used Chemelec inductance calculator and got results:
For 10 inch inside diameter coil (256mm) - O concetric coil
coil lenght: 0.2 inch (5mm)
wire diameter: 30 AWG or 0.27 mm with varnish
turns:117
inductance:7.1mH
I think that calculator is very, very good .
Everything looks fantastic, but no, no my friends! My freaky multimetar "told"
me the coil inductance isn't 7.1 mH (that should be RX coil), but 9.8 mH!

Let's say y is specific resistance (I haven't that bloody letter).

R=y x l/S then l=R x S/y

y for copper is 0.0172 ohm x mm2/m
resistance of my coil is 33 ohm

S=r2 x 3.14 ( I haven't bloody pi too) S=0.125 2 x3.14=0.0491 mm2
l=33 x 0.0491/0.0172 l=94 m

So, wire lenght of my coil is 94 m.

let's calculate on other way:
O=2 x r x 3.14 O=0.256 x 3.14=0.8 m

0.8 x 117 turns= 94 m - the same results.
So what, you can say, but now I am sure the number of turns is correct-117
And what now? Should I trust to my multimetar , it looks good, think it isn't from China, but who knows? Or should trust Chelmec?
Immediatly need help... help... help...
Yours Hush

Using my own calculator (see attached) I used 127mm inside radius, 0.27mm wire thickness and 117 turns. This gives an inductance of 8.98mH, which is closer to your measured result. How accurate is the value of the inner radius? This is a sensitive parameter, and only a few millimetres can change the inductance significantly. The calculator also shows a coil thickness of 5.62mm, whereas you have 5mm. Since the calculations assume a square cross-section to the coil, your's may be elongated.
Hope this helps.

By the way, Chinese multimeters can also be good.

[ApBerg]

Hello Hush

Good results. The transmit freq. is the sourse for al the things that are going to work. The 4024 makes the freq for the audio sound, so if you chance the transmit freq. then aslo the audio sound is going to chance.
I think that it is ok that the sound is there for some seconds, this is the batt check, but I think the sound has to fade away after some seconds, this depends on the power sourse you use, the higher the voltage the longer the sound stays.
Let us know the results for your OO coil ?

Succes

[tiktak]

Hi

Hi,
Max.
Is this what you talking about?But what is this diode?
1N4148?

[Hush]

Hello Hush.

Think you want to make a open centre coil ?
Look at post no: 22. I made some opencentre coils, works well.
For the 25 cm coil the 117 turns are to many.

You can connect your coil to the transmitter part from the goldensabre and look for the freq that is given , use for golden 15 nF cap, freq must be somewere 14 kHz, if lower freq then reduce the 117 turns
Good luck

Ap

Hi ApBerg, thank you for replay!
As you wrote, I've connected coil on transmitter and frequency was 11.7 kHz
Then connected cap 15nF parallel with coil, like you suggest, freq drop at
8.9 kHz.All the time I heard constant tone in head phone, is it normal? When connected cap, tone was lower.
About coil: that should be double O coil like Ivconic's. Nexus made similar.
To Geo: very good idea,maybe try it later. Now seems my multimeter was right! I' try to reduce number of turns.
ApBerg,Geo,man from Mars thanks a lot!
Salute you!

[Leto]

555s

For Ivconic:
this circuit can be also usefull (from JF1OZL) -> NE555 is used as a free-running oscillator. The oscillated frequency is 166kHz. This frequency is too high to be heard by the year of the man. In normal oscillator , the time-controlling capacitor "0.0022uF" is connected to the ground. But in this case, it is connected to the output of the audio amplifier. Therefore the width of the pulse is modulated by the audio signal. And it is heard by the speaker..

[Max]

"Ivconic what do you think can I use CD3240 insted of LF353?
Will this afect performance?"
I checked this today. Havent seen any differences.It can be used
to replace LF353. (CA3240)
"Are you using metalbox for device and ground all to box?"
I am using plastic box.

"Ivconic what is this coin 1cm?The smalest I think is 1,5cm D!
please check again!If this is true than I am not even close to the
results that I have to achive!!!!
Can you preforme air test with 1 euro coin and post results please!"
Yes, you are right! Again i made stupid mistake by claiming something
without checking it first!? I am using that coin for several years, never
occured to me to measure it!? Somehow i conceived it is 1cm...?
Truth is; it is 2cm diammeter!? This really changes all your points of
looking at my results?
Yes, i agree,it would be almost impossible to detect such small coin(1cm)
with 22cm DD coil.
I have problem,issue with myself; things i am used to "see" my way are never
checked preciselly...Sorry!
Distances i already reported are TRUE. Do not have doubts.Only coin diammeter
was wrong. Actually it is 2cm. Dont know why i made that mistake?
This is international forum.I am also visiting many other simillar places on
the net. Have conntacts with many people, mostly i do talk in inches....must
be that i memorized this as one cm instead one inch...later all mixed up due
very tough rhythm i've been living lately. Very exausted, so few resting moments.
"Have we to split hairs here ?"
Yes Max, i agree with you. But this time TikTak is right, 1cm more does really
make difference! Although it is not easy for me to admit, i made huge mistake!
Erolunall, to tell you the truth; i never tested it on large items. I made it
for coinshooting, and coins&small items are only what interesting me.
But, if you wish i will test it these days on larger items and later post
results here.
"And NE566N what do you think is this make differance in audio.Ivconic tell that
he search for another solution!This mean that its not so good modification."
Yes it is worth of trying. Works better than without it.But i want some more,
that's why i am looking for another solution.
About LM566, well, problem is in signal level. It need voltage to produce certain
frequency - VCO. But at TGS output signal level is not compatible with what we
need to drive LM566. Some kind of converter is needed.
Realizing that, i had to think other way,so after a while i just put J107 to trigg.
it to -12v. It is sort of trick to provoke LM566 to start working. But sound is
still "monoharmonic",short and anoying. Benefits are louder sound and abillity to
adjust frequency of audio....
I am not satisfied at all with this. I imagined it other way. If we could use
variabile TGS output voltage to drive LM566 in manner to change audio frequency
respecting voltage changes at TGS output. That would be some progress! i experimented
some time, but without succes. Something is missing? I can not find proper way
to make level conversion there.
TGS output is in range -4.xx - +3.xx volts. Only positive part is starting LM566.
Another problem is small "resoultion" in those +3.xx volts. All changes in
frequency at LM566 are so fast i just cant hear differences.
I think 4046 would do the job better, only dont have clue how to use it!
Yes, i have all those schematics with 4046, but wired up in quite different manner,
not useable in this one...Need some time to think about it.


Still wandering! There is some 555 to check.....What do you think?

Hi,
could do the job but still think that 4046 is too cool for that.

Circuit like this could do the job and you can set upper frequency of e.g. 100Khz... so getting about 20Khz for a 3 volt swing.

Components need to be modified, this came from a Tesla coil circuit.

BTW have you looked at Leto's post of circuit by Rumensat (second picture)... kind of VID using RGB led, if we wire that and trigger the vco using preset for frequencies we could gain multi-tone id for coloured metals. Do you think could work ?

Kind regards,
Max