homemade detector as seen on Meteorite Men

[Hitman]

On the show meteorite men they make a large scale detector out of pvc and wrap the coil wiring themselves. How realiable is this? Is the size of this homemade coil make the instrument detect deeper? How many feet of wrapped wire would it take to make this work properly if it were 6 x 6 feet square? Any schematics out there to make one that has been tested? Thanks

 

[sctoddc]

will be watching this thread, I think I saw the episode you're talking about, and was wondering the same thing.

Todd

 

[Carl-NC]

The type of detector used for this is Pulse Induction and, fortunately, PI is pretty forgiving towards coil parameters. Therefore, homemade coils for PI are fairly easy. For a typical 300uH inductance, a 1-meter diameter coil has 9 turns of wire, and a 2-meter diameter coil has 6 turns of wire.

- Carl

P.S. -- see Geotech for lots of PI projects.

 

[Reg]

Carl is correct. PI's, at least many of them are very forgiving when it comes to building coils, so building a larger coil is not a big deal. Since large coils are not operated at a short delay, then even the inductance isn't totally critical. In other words, lets say you want to build a 2 meter coil, you could use 6 turns or even 7 or 8 turns and make the coil work. The key is being able to change the delay and the circuitry involved.

In the case of the large coil, the object you would be looking for has to be big and as such will normally have a long time constant, meaning you can turn the delay up so a larger coil will work. If the delay is turned up enough, then even shielding may not be necessary. Also, ground balance may not be needed also.

Personally, I would add shielding to minimize external noise.

Reg

 

[relicswinger]

Any schematics out there to make one that has been tested?

This was an important part of the original posting. Does anyone have info on building one?

 

[Carl-NC]

Any schematics out there to make one that has been tested?

This was an important part of the original posting. Does anyone have info on building one?

P.S. -- see Geotech for lots of PI projects.

Click on the word "Geotech"

 

[Roger Mn.]

Check this out. Sounds like a good price for $570 and you make your own coil using the wire sent with it .

Pulse induction metal detector PI 807.

 

[Rob in KS]

When I first saw that detector, I wondered the same thing. When he was here in KS ( before the TV show), Steve Arnold had someone modify a Pulse Star II to use a large coil. My 3 footer is 11 turns and 572uH. It's in the shop now, it seems to have gone deaf. I suspect the electrolytic caps have gotten old. If you want to know more, follow Carl's link