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No i didnt wanted 45Vpp, i just mentioned that range is 10-45Vpp when turning trimmer from one end to another.
20-25Vpp is real goal at TGSL. Need to be checked.
20-25Vpp is real goal at TGSL. Need to be checked.
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Hi,Originally posted by ivconic View Post
if that's the goal it's simple I think.
Need extra voltage at supply rail for oscillator... in the 20-25V range.
We have alreay 8v regulated... but also (usually) a 12v battery or more...
A simple switching SMPS can convert the 12V in 24V very easy... but will introduce some noise also. But you can shield whole SMPS section in a metallic box... then filter output rail to catch residues of hi-frequency commutations... and have a short parassite turn on transformer... that will absorb much magnetic energy from there.
I think is possible this way getting 24-25V but also more, if needed.
A 78s40 will do that simply.
Then simply change some oscillator component and you'll run at higher voltage but pure sinus.
PS... if don't wanna mess with SMPS use two batteries 12v in series... and get 24V then... use also a low dropout stuff and you'll run easy at around 24V with just 24.3 or more at input from batteries...
A charged gel battery gives usually 12.7v at full charge and just 11.95 at full discarge... so... you'll run at start with 25.4V to get 24V, not bad. Then could run good till 50% of charge... and considering consumption is low , e.g. 2Ah can last hours and hours.
Kind regards,
MaxComment
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Sorry...
made a mistake in last post: if run osc at 24V you'll get around 48V at output tx... the double.
So ...an easy solution is adding a new regulator LDO to the 8V one: this last will produce 12V from e.g. unregulated gel battery output (12.7 at full charge as explained).
The LDO must be 0.3V kind or less.
Then the 12V rail you'll use with oscillator only.
The battery will last several hours if e.g. 2Ah cause TGSL need few current, till reach the LDO minimal operating voltage and so some signaling of battery "discharge" will be employed...
Kind regards,
MaxComment
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But you need to remember that a doubling in depth requires a 64x increase in TX power. So even doubling TX power doesn't give a good return for your investment.Comment
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TGSL
Dear Ivconic
could you please tell me how do i connect Mono mode for yourTGSL1265 last.zip
actually i am happy with the resault but i need more depth.
i have searched all posts but i couldn't find it
please help
best regards
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How do you get such high voltage from 8V supply? Must be very resonant, but then would not be square wave, would be quite sine wave.Originally posted by ivconic View Post
Something is not clear about this.
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I tried simulating the oscillator with LTSpice -- cannot get oscillation so far. Strangely, if I disconnect base of BC547, I get small oscillation, under 1 volt. Are the values correct?
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Correction: I had wrong inductance. It oscillates, very jagged as you said. Very strange, will require some analysis.
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I think it is working like ignition spark coil with those values....
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Regards,
-SBComment
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Actually i use DC 10v ps to run it.Originally posted by Max View Post
LC tank 10nF+5.8mH. Transistors are BC327 and BC547.Comment
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Nooooo! I am not trying to double the depth. I just want to rise power a bit. TGSL as it is, is already pretty descent on coins. I am doing this experiments to see if there is any closer TX power influence on rest of detector, esspecially on audio behavior.Originally posted by Qiaozhi View PostComment
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Yes strange and interesting. Signal shape is almost a sinus, but not exact sinus. I will take a shot and post here later.Originally posted by simonbaker View Post
More i think, more assured i am; that problem is in unapropriate relation at LC tank. Some parasitic sideffects occurs there. Is not that theoretically this can not work, but in practice it can not work good due tolerances and quality of material used. To void problems in future it is better to redesign it and adjust optimal values which will work in a "middle" of range, calm and without sideffects, even if components are not 100% right. Should rise C and lower L. But it will need me to make another coil. I used one already finished and adapted for TGSL. Wouldnt be a problem to make another coil.
Damn i never analyzed circuitry of some newer Tesoro. Is there any chance somebody to post here just TX part of some new Tesoro? Cibola, Vaquero,Tejon or simillar? Just TX part...
(Dang!!!)
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Originally posted by metaldetector107 View Post
You have everything here; schematic and pcb. Follow schematic and connect small pcb to main according this schematic:
http://www.geotech1.com/forums/showt...le+mod&page=97
Wasn't hard to search back the pages and find it.
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TGSL
Dear Ivconic
thanks but i asked for last TGSL the one with BD140, any should i take same procedures?
kind regardsComment
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Hi,Originally posted by Qiaozhi View Post
yes I know, I remember also... but think too tgs has small tx power... so some volt more there could just be positive I think.
On the other side I really don't wanna play with something that has e.g. 50Vpp at oscillator or more... cause I know device will become more and more unstable.
I think it's an easy experiment... two batteries needed and few mods... could be nice to see how performs.
Kind regards,
MaxComment
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Yes, if you keep raising C (or lowering L) with that oscillator, you eventually get good sine wave, but normal lower voltage (around V+ magnitude).Originally posted by ivconic View PostYes strange and interesting. Signal shape is almost a sinus, but not exact sinus. I will take a shot and post here later.
More i think, more assured i am; that problem is in unapropriate relation at LC tank. Some parasitic sideffects occurs there. Is not that theoretically this can not work, but in practice it can not work good due tolerances and quality of material used. To void problems in future it is better to redesign it and adjust optimal values which will work in a "middle" of range, calm and without sideffects, even if components are not 100% right. Should rise C and lower L. But it will need me to make another coil. I used one already finished and adapted for TGSL. Wouldnt be a problem to make another coil.
Damn i never analyzed circuitry of some newer Tesoro. Is there any chance somebody to post here just TX part of some new Tesoro? Cibola, Vaquero,Tejon or simillar? Just TX part...
(Dang!!!)
BTW: If you put diode between tank and transistor collector (plus side of diode on collector), you get symmetric waveform, still spiky, but interesting.
It would be cool to get good sine wave at 60V -- I think somehow possible with circuit that pulses the coil at just the right time -- I suspect can find such with google, or mod this one.
I am very interested in such "super-resonant" designs for super-deep detector. Also I have a hell-of-a-lot of 24 gauge wire I need to use somehow...
Attached is spice circuit for playing.
Cheers,
-SBComment
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I think it would be interesting detector, but hard to sell because tricky to operate maybe, so not common for commercial detectors sold today. Probably dynamic range increased, difficult not to overload detector for shallow targets -- but who cares, it would be specialty deep detector for beach, caches, etc.Originally posted by Max View Post
Imagine: have a switch on detector for high voltage "deep" mode...
Regards,
-SBComment
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Send me $500 via Western Union and i will help you. Fair enough i hope!Originally posted by metaldetector107 View Post
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