HI
Hi,
scevlik!
Nice to hier that you have make good coil.
Where are you from?
Now next step is to make good nulling!And the things will be alright.
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Hello
I have redy my coil DD 255x137 work on 14.72KHz.
TX have 23.8 ohm and RX 25.8 ohm.
How i can set up this coil because detect 30mm coin only on 16cm,and disc not work correctly.Please help me it is my first coil and detector.
Thanks.Leave a comment:
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Originally posted by Aziz View Post
"...which is driven indepently in real-time via software..."
In real setup (machine), ultra fast uPc must be involved there.
I have certain working experiences with White's. Software in those is sometimes to slow to resolve some soil conditions. At disc functions same case. White's included "Averaging" function very smart there. Yet it is not perfect solution.
Again,theorethically this is probably the best solution....yet, practically it could lack....take my word on this.
"...This is possible, when the shape of the coil is perfectly symmetric (not causing much complex phase errors)...."
I dont think this is possible to achieve with classical approach, using wires in coil. I suggest you to start thinking more seriously on multilayer printed pcb coil. Possible to achieve perfect physical symmetry. Only way so far.
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Hello ivconic,
I am doing the ultra-balancing via applying a correction magnetic field with an extra balancing coil (few windings), which is driven indepently in real-time via software (laptop MD). The strength (coil current), frequency and phase of the balancing coil forces the IB-coil to be perfectly balanced on the specified frequency. This is possible, when the shape of the coil is perfectly symmetric (not causing much complex phase errors).
I observed similar behavior of balancing the coil by placing metal particles nearby the coil. But this decreases the sensitivity of the MD.
Mechanical balancing is the best option. One should use some plastic screws and nuts for balancing the coil somehow.
AzizLeave a comment:
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Aziz i beleive your software can calculate perfect balancing conditions.
But in practice that is almost impossible to do, especially for amateur like myself,especially in a domestic workshop like i have. So...that remains pure theory for me, for now.
Only...!
Only if i change my method of balancing. I saw pretty funny way of obtaining better balance once;
man nulled coils so,so..glued and let to dry. Later added few small metal fragments somewhere on coil, positioned in manner to improve balance while monitored on scope.Fragments are glued also and remained there permanently. Yes that coil was balanced much better than i can usually do.
Only one question left from me; is it proper method?
"Foreign" body, like added metal fragment in coil could possibly affect and distort real phase behavior in working on the field!? I do have real doubts in this. Thats why i never done simillar with coils for IB machines.
Any other method? I would like to know...
Regards!Leave a comment:
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"...Played around with coil nulling, got down to 0.95mv AC. Was increase in depth by 2-3 cm, so think I'm on right railroad.....
But I don't think my now coils can null lower..."
Yes, some coils cant null lower, i noticed that also.Those finished in a scrap box.
Why?
TX and RX cois are probably to close to become resonant. Make more difference in number of windings. Add 2-3 windings more on RX.Later you will be able to null them easilly.
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Regarding oscillator managed by IC, this is of old Compass year 1976, excellent detector.Leave a comment:
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Hi,
Hi,
and also this added area exept 12,75.How much it is 1,5cm?2cm?Leave a comment:
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Hi,
Hi,
Max.
What is the dimension here ?1,6cm?Because I can see clearly.
ThanksLeave a comment:
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Hi,
if anyone is interested on a powerfull LC oscillator, the basic circuit is shown below. The output of the op-amp can be driven with pnp/npn output stage, to increase the drive current.
I have tested this LC oscillator type and it delivers as much power, as you need.
Here the source for this LC oscillator (german):
AzizLeave a comment:
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Hi Molzar,Originally posted by Molzar View PostIvconic,
Played around with coil nulling, got down to 0.95mv AC. Was increase in depth by 2-3 cm, so think I'm on right railroad.....
But I don't think my now coils can null lower. I spend big time making small ajusts and will not go lower. Will try making "better" coils using methods described. I think this "key" to good depth.
When I swapped Tx and Rx coils for Rx shift left / right experiment I got extra surprize!!! Noises and beeps all go away! So I keep that way for now.
May not post for few days as there is big party here in few days and have to turn me "workbench" back into Racetrack for childs. I of course will be collecting much cans and bottletops from favorite beverages
for MD experiments
Oh...... wanted to ask Max about scope pictures he made with test point maps. Did you use 9x8 Tesoro or Homebrew DD coil for test pictures?
Thanks,
Molzar
at that time I used an homemade DD coil... I use often on the bench also for other MDs. It's 100/105 recipe DD, nulled at about 15mV peak-to-peak.
Kind regards,
MaxLeave a comment:
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Ivconic,
Played around with coil nulling, got down to 0.95mv AC. Was increase in depth by 2-3 cm, so think I'm on right railroad.....
But I don't think my now coils can null lower. I spend big time making small ajusts and will not go lower. Will try making "better" coils using methods described. I think this "key" to good depth.
When I swapped Tx and Rx coils for Rx shift left / right experiment I got extra surprize!!! Noises and beeps all go away! So I keep that way for now.
May not post for few days as there is big party here in few days and have to turn me "workbench" back into Racetrack for childs. I of course will be collecting much cans and bottletops from favorite beverages for MD experiments
Oh...... wanted to ask Max about scope pictures he made with test point maps. Did you use 9x8 Tesoro or Homebrew DD coil for test pictures?
Thanks,
MolzarLeave a comment:
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[quote=erolunall;72099]Hello
My friend asked help for not working TGSL works that he attach his works below links.
it is not giving sound.
İf anyone find any error please write.
Regards
Erol
http://www.postimage.org/image.php?v=PqS6M3i
http://www.postimage.org/image.php?v=aV21O9vi
http://www.postimage.org/image.php?v=aV21OjtS[/quote]
First check voltages. Plus is 8v and minus approx. -6.2V...
Than check oscillator (2N2907). Measure frequency at collector (coil must be connected in all cases)...
If there is approx. 14kHz on collector than trace that frequency up to pin 1. of CD4024. If there is not any frequency reading on 1.pin and there is on collector of 2N2907 than buffer 2N2222 choked it.Change 2N2222.
If there is 14kHz on 1.pin than check for f/2 on 12.pin of CD4024. So must read approx.7 kHz there. If not, CD4024 choked it, replace 4024.
If there is f/2 on 12.pin than check for divided transients on 1N4148 diodes on 5,6,and 9 pins on 4024...Those are forming composite audio.
If everything appears to be good...than just be sure that minus (-6.2V) is present and good. If yes, than chopper works good. If not chooper is choked.Replace 2N2907 and 2N2222 in chopper with BC557 and BC547...(sometimes 2N... transistors do not work there???)...
If chopper is ok and you have proper minus voltage...than check MPSA13 orientation...pins are EBC not CBE...
Sheeeesshhh! I am exhausted for now....
Check this first and let me know...
We will continue later....
Buaaahh....
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