White 3900D

[getsa]

Hi,
Just FYI - having an eye the schematic "CSCOPE" and the PCB, you have shared I recognized my on hand drawn creations!!! Some time ago I shared them in a Bulgarian MD forum and а dishonest guy abuse with my work. Of course, I appreciate your intention to repeat the project! Fingers crossed!

[gurdal]

device perfect coil a little hard

[blobber]

Better to make a well proofed VLF design. So far I had good success with TGSL, IDX-Pro, Bandido 2, Krot, Fortune M2, many M3 and Fortune Pro2.

[blobber]

Hey Marty, what's going on? Your comma key is broken? I think this detector is only waste of time, it was my first attempt long time ago, to make a VLF machine, but with poor results. Maybe my fault, because lack of experiences.

[MartyJ1963]

Is this project still going DB? Regards, Marty

[MartyJ1963]

Any news yet DB?,,,It's been a while,,Lol. Regards,,,Marty

[MartyJ1963]

Nice to hear your progressing,Looking forward to your next posts,,,,What is the coil data for this project please? Thanks, Marty.

[dbanner]

Any news on progress yet DB? Can you let us know if it's worth building or not please?,,,eager to start a new project, lol. Thanks,,,Marty.

I have made some progress, just finished winding some coils. Now I have to finish populating the PCB. Some components are still missing, like the CA3140 chip. But I will use a substitute. I hope to begin testing in earnest in a couple days.
I made simple DD coil, 8 inches in diameter. It is rough but good enough for preliminary testing.
I have no doubt that the thing will work, only question for me is what will be the discrimination. This will be the tricky part, whether or not the Rx coil is left untuned.

[MartyJ1963]

Hiya Nandor,,,Thank you for the information, I very much appreciate it. I have been searching for these chips to build a few other 'Old' detector projects as well as this 3900D project. Thanks again. Marty

[Nandor]

Hi

Marty the is a site were I,ve found CA3140 from Intersil - try tme.eu it has 1.15 Euro price

No commercial intention just to help you

[MartyJ1963]

Any news on progress yet DB? Can you let us know if it's worth building or not please?,,,eager to start a new project, lol. Thanks,,,Marty.

[ivconic]

You are right! I wrapped 10 turns around pencil and measured the width and divide by 10. Diameter is 0.40mm!
I have microwave oven transformers in the junk box, the secondary windings are very thin, maybe this will be good enough, but now I have to cut the core to get the wire out.
I feel like vagrant of electronics sometimes, always having to scavenge around for basic stuff. But that is the fun of poor man's hobby.

Story of my life.
Now, so many years after; even with money enough to buy material: i still find my self in a mess of dismantled devices, parts, wires etc.
I guess it becomes part of my mind, during the years. And also there is some beauty and joy in that too.
Lot of fun too!

[dbanner]

Usually it is 0.4 to 0.5mm gauge.
Not suitable for RX coil.
You better try to find some transformer to dismantle.

You are right! I wrapped 10 turns around pencil and measured the width and divide by 10. Diameter is 0.40mm!
I have microwave oven transformers in the junk box, the secondary windings are very thin, maybe this will be good enough, but now I have to cut the core to get the wire out.
I feel like vagrant of electronics sometimes, always having to scavenge around for basic stuff. But that is the fun of poor man's hobby.

[ivconic]

I have come to an obstacle. I do not have enough wire for 16mH coil.
Now I have to look around the place to salvage some wire from somewhere. I have some old "big Back" TV's, I could get the wire from the degause coil or maybe from the deflection yoke.

Usually it is 0.4 to 0.5mm gauge.
Not suitable for RX coil.
You better try to find some transformer to dismantle.

[dbanner]

I have come to an obstacle. I do not have enough wire for 16mH coil.
Now I have to look around the place to salvage some wire from somewhere. I have some old "big Back" TV's, I could get the wire from the degause coil or maybe from the deflection yoke.