Sir Ruben, how It's going? Your PCB looks good the component very convincing, the coil part, how many coil you have? I make five coil mix with my DIP version of vlaser smd origin design. Have you try zoomix coil the one with 28mh RX ? The coil making and amplitude adjustment is my worst part as I lack of understanding, but vlaser version the one without static channel are simplest
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Building Wolf Treasure [Tesoro Lobo]
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Originally posted by Op04 View PostSir Ruben, how It's going? Your PCB looks good the component very convincing, the coil part, how many coil you have? I make five coil mix with my DIP version of vlaser smd origin design. Have you try zoomix coil the one with 28mh RX ? The coil making and amplitude adjustment is my worst part as I lack of understanding, but vlaser version the one without static channel are simplest
I only have the coils that I made the ones mentioned in message # 25.
What is the Vlaser version you are building?
Could you upload it to the thread, maybe I would encourage myself to build it?
I have not tested the zoomix coil, nor do I know its capabilities. I am new at this.
For me it is also difficult to make the coils and adjust it; You should keep in mind that LCRs and multimeters do not measure equal to the capacities of the coils and capacitors.
For the amplitude according to what you learned is that you should try not to deform the wave in the highest peak, you have to keep a clean sine.
I would like to see your DIP Vlaser version.
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Originally posted by rolling rock View PostAlso, in post 28. Again, test point B (a different B).
As KT315 pointed out, that "square" wave is looking lopsided, agree?
Supposedly, we have gotten past that ugly waveform, because otherwise, you would probably not have a nicely symmetrical, low distortion sine wave at point A.
SO, what is the story? Please do not overlook important details or you waste everybody's time.
Check again, using the high dollar scope. That should be a 50-50 square wave, or at least have almost immeasurable deviation from being square.
Is it necessary for the output signal to be 50% high and 50% low at 555 pin 3?
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Hi,
It's there on post #57 I don’t have more picture, I have to pull from the case, sorry can't do that now, last version from vlaser, the pcb smd enlarged to fits Dip IC, not for long only working for a month, so I don't want to discuss here, it was the third board adds to my fail. I hope you make this version working, I still build a PI project now, I believe you will success building lobo.
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Originally posted by Ruben2000 View PostThanks for your rolling rock advice.
Is it necessary for the output signal to be 50% high and 50% low at 555 pin 3?
Seriously, any self respecting '555 (no matter what flavor!) should be able deliver 50-50 duty cycle at 17500 or even 20000 Hz. (Just my humble opinion but surely, I am uninformed.) So, that really was that a lopsided waveform? Good, I thought maybe it was just because I was sitting sideways, because I was sitting sideways, therefore I was a little concerned. Too much, really. Just remember, KT315 saw it first.
If you have nice symmetrical square waves coming out of your phase references (U5-1, U5-7, U6-1) then you may have nothing to worry about. That is for you to decide. Non-symmetry may cause some performance loss, but it won't break your machine.
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Originally posted by Ruben2000 View PostIs it necessary for the output signal to be 50% high and 50% low at 555 pin 3?
Those would be at U7-7 and U5-1. Turn the ground pot to zero, then do the same for the 100% position.
*You know, the "spice simulation is not real blah blah" and I agree 100%.
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Originally posted by mermelado View PostHi:
In a previous thread the coil construction is specified, but not the offset between TX and RX is this 20 degree for DD coils like TGSL?
For my detector I am working with the Lobo rx amplifier, but then I am attempting to borrow the phase reference circuit from Tesoro Aztek. Aztek uses a differential coil and amplifier, and initial phase setup works differently from Lobo, but I found an easy way to rotate the references to get everything to line up correctly. Sorry, but my easy fix will not work quite so easily with the stock Lobo circuits. I will try and post some screen shots from my Lobo LTspice simulations when I can find a place to plug my laptop into the internet. It is quite revealing to be able to watch signal phase relations moving around as frequency is varied. One popular method of checking alignment is that you should be able to cancel a ferrite rod or toroid with your ground control turned way to the left.
Lobo does not use a tuned receiver coil, it relies on selecting R and C values around the rx mplifiers to form a bandpass filter. But we need to phase the rx output, and that probably will not happen by accident.
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I think I was wrong about that negative peak. Look for the positive peak to slightly overlap the G phase reference. Too much overlap and you will lose ability to cancel large silver items which may be a non-issue, but I don't know what happens after that.
As I wrote previous post, I was thinking that there is an inverter in the signal path, which is incorrect. I don't have any laboratory or equipment, at this time, so I am having to trust what I see on my laptop. Sometimes I get the + and - signs mixed up.
Ooh, it's when I get Right vs Left all mixed up, well that can be a hairy mess.
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Originally posted by rolling rock View PostI think I was wrong about that negative peak. Look for the positive peak to slightly overlap the G phase reference. Too much overlap and you will lose ability to cancel large silver items which may be a non-issue, but I don't know what happens after that.
As I wrote previous post, I was thinking that there is an inverter in the signal path, which is incorrect. I don't have any laboratory or equipment, at this time, so I am having to trust what I see on my laptop. Sometimes I get the + and - signs mixed up.
Ooh, it's when I get Right vs Left all mixed up, well that can be a hairy mess.��
Edit:
I just found online a PDF related to the construction and calibration of search coils. I share it here, in case someone can be useful.
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Originally posted by rolling rock View PostI think I was wrong about that negative peak. Look for the positive peak to slightly overlap the G phase reference. Too much overlap and you will lose ability to cancel large silver items which may be a non-issue, but I don't know what happens after that.
As I wrote previous post, I was thinking that there is an inverter in the signal path.
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Originally posted by mermelado View PostThank you very much for that magnificent explanation, which will help me to take my first steps. But I confess that I do not understand that the RX coil is not tuned. In the schematic I've seen, C5 is in parallel with the coil, which in theory forms a resonant LC circuit.
I believe spice simulations help me get the circuit in motion, but I do not know what exactly will happen as a properly nulled coil is introduced, in the real world.
Will the receiver phase get advanced (I think) or retarded, and exactly how much, I do not know. I hope to find out in person. Keep in mind, the factory Lobo came with a concentric coil, not a DD, and they will each align somewhat differently, and well, everybody knows that.
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