Tesoro Lobo news

[Davor]

Boy I must be goophy! I sure cant find them.

Actually you can, see http://www.waynekirkwood.com/Images/...ap_Sound_6.pdf

There was an excellent series of articles by Cyril Bateman back in 2003 in Electronics World. He made a rig with notch filter and fine oscillator etc. and tested capacitors for distortion to prove if there is such a thing as "capacitor sound" and - he found it. He done it so thoroughly that it is worth reading it through. Whole shebang is found here:
http://www.proaudiodesignforum.com/f...&t=153&start=2



OT: That was practically the last big thing that Electronics world produced. They changed people in charge and the whole magazine turned yellow. I did not renew my subscription after that, and the last few issues were a torture.

[WM6]

Hello Eugene

The Lobo with a single sided PCB is a modified versus ( in relation with yopur comment ).

Why the double side: I did it to simplify wiring, I gathered the various connections on both sides of the card and also there is less bridges in the middle of the circuit.

But if you want to make a single side PCB use this one.

Hi silverdog, do you like this Gold detector LOBO PCB?

I am interesting in it (as kit too), and as we can read here some others too.

[porkluvr]

Thanks Amtech, Legaucho, I got the package.

The two doc files are operators manuals in French and English.

After opening Tesoro_Lobo.rar, I have a problem with these new transmitter circuit values. In the file Coil_Info.gif he indicates 2.0mH for the TX coil and I can agree with that value, using the numbers in the picture (although I have no idea what is referred to by "(x0.670mm)" so I'll ignore it)...

So, using L=2.0mH, with C=8.2nF in the XMIT tank as shown in the schematic Tesoro_Lobo.jpg, I calculate a resonant frequency of 39kHz. Why would we want to tune the tank to the second harmonic of the drive frequency? I would use 1.33mH and 47nH and tune 20kHz.

Also I can't find a RV4538 listed anywhere, but I believe MC33178 is a good substitute for the original LS204.

I have a bunch of SMD parts and I might try and pick up where I left off. Of course I won't be able to use any of the existing layouts but I could look to them for some guidance. My biggest hangup has been being determined to use 9V batteries and the need to include a switch mode power supply to make that possible. Me stubborn.

edit: Using 33nF with a 2mH coil would get you tuned to around 19.5kHz.

[Legaucho]

Again me

If you talk about this : http://elfouino.perso.neuf.fr/Tesoro/

I have draw the PCB in function of russian information coming from one internet site but I don't remenber the address (sorry). I never try it, it's different of original one.

[Legaucho]

Hello Eugene

The Lobo with a single sided PCB is a modified versus ( in relation with yopur comment ).

Why the double side: I did it to simplify wiring, I gathered the various connections on both sides of the card and also there is less bridges in the middle of the circuit.

But if you want to make a single side PCB use this one.

[homefire]

That will work.

Send them when ya can.

[amtech2005]

I will send you the url link via email or pm , if not I can send the download of 20 megabytes.
I think my snail-mail limit is 25 mb on attachments . The Lobo worked great with a single sided PCB so I want to keep the project original also .

HH............Eugene

[homefire]

Open Office may open those documents.

Yes the Inductance of the coil should be measured at the operating frequency be sure.

[porkluvr]

Hello Everyone . I downloaded the Lobo rar-zip package of 19 megabytes from Fr. link and everything looks great .

Regards............Eugene

Where is that? Do you have url you can post?

[amtech2005]

Hello Everyone . I downloaded the Lobo rar-zip package of 19 megabytes from Fr. link and everything looks great . Only two word-pad document folders did not open , maybe outdated.
I am just wondering the Original Lobo which was manufactured as a single sided pcb board , why the pcb lay-out was changed ?

The Lobo was originally engineered as a single sided . Signal problems may occur ?

Regards............Eugene

[amtech2005]

Not measuring inductance Values Correctly ?

Hello Legaucho , Porkluvr , Everyone .

The reason why over the years there is always a problem with transmitter / resonance circuits in relation to correct schematics , circuit simulations , measured inductance problem could be the output frequency of the testing device !!! How can you honestly say a search-coil that is measured for the Lobo at 1.367 millihenry tx is a accurate inductance reading , injected with a 1khz signal ?
Inject the search coil with a 20 khz signal to get a proper inductance . Foma's 17.5 khz Lobo best operating frequency was because the inductance of the coil was measured wrong .

Another example was the Relic Hawk project problems of TX and RX . A 5khz operating frequency [coil inductance value] will not be correct injected with a 1 khz test frequency !!
Measured Capacitance values is another big subject too .

I never did read any spec sheets yet on LRC meters [output frequencies] till today !!

Regards..............Eugene

[amtech2005]

Hello bernd

I do make myself , I use the services of PCB-TOOL.com. Link in german https://www.pcb-pool.com/ppde/index.html

Best regards

Board Looks Great , schnell ist gut !!

Regards..........Eugene

[Legaucho]

Hello bernd

I don't make myself , I use the services of PCB-TOOL.com. Link in german https://www.pcb-pool.com/ppde/index.html

Best regards

[bernte_one]

hello legaucho

clean work looks good
could you deliver two boards to germany
i have not a good hand for making double sided pcb

regards bernd

[Legaucho]

Hello all

The first step in the achievement in double-sided PCB.