Need a larger coil for a Metal Detector

[SikFuk]

Hello, i have a meal detector, it has approximately 3" coil, so it can only detect at approximately 3" deep. I want it to be able to detect much deeper. As i understand i need to build a larger coil for it. I do have another metal detector with a larger coil, but i don't think i can simply take the coil from one detector and put it on another one. Where do i even start. I already took it apart and have the insides on my table. Where do i start?

[pebe]

There are basically three types of metal detector, but unfortunately your photo is not much help in deciding which type yours is.

If it the simple BFO type then you only have to wind a larger coil with the same inductance. But if is an induction balance type or a pulsed type then things get a bit more tricky.

Here is a link to a formum for metal detectors, and if you can identify the make and model of your detector, there will be many keen people there who can be more helpful.

http://www.geotech1.com/forums/

[SikFuk]

The metal detector is a Vibra-Tector 730. Thank you for the information i will look on that forum.