Italian VLF design

[dom44]

to hard to keep track of them all ivconic this version has a nice pcb and does work well
handy for a small portable unit.

[ivconic]

Can't anyone tell it is a Tesoro?

Long time seen on this forum already.
TGSL topic is HUGE and this version is sunk somewhere there.
If i recall correctly; i got it from Nakky or ApBerg, several years ago.

[dom44]

Here is the redrawn schematic I think it should be right

correct one others have minor errors.....

[dom44]

I will have to redraw it give me a bit of time it doesn't say the frequency just gives the transmit coil inductance and that is a bit hard to read i would say anywhere around 15khz, my coil was putting out about 50khz on the bench while i was playing around with it and was still showing signs fer rite reject with ground balance and iron discriminate showed signs of working as well but i have to play around with it to bring it down in frequency as i am using a 100mm coil, but picks up a mans ring at about 160mm with that coil. important thing to note is there is a 1meg resistor in parallel with D2 on the board that is not marked on the schematic but you can see it on the photo.
this is the original parts placement.
if you want the sprint layout i redrew let me know.



also just found this info while searching

[waltr]

PCB looks nicely done.

Schematic is a little hard to read. Any better image available to post.

What frequency does the TX run at and what are to coil specs.

[dom44]

I was on an obscure forum in metal detecting when I came across this design I have just built it after redesigning the PCB the image is not very clear but it worked first go and is an easy detector to build
I have not tested it yet in the field, I am building it into a small hand held detector for checking small patches for nuggets or to search up walls.
My search coil is only 100mm diameter but shows good sensitivity I used an ne5534 for the coil amp, and a tl074.