I have the K7102 metal detector kit. I have assembled the unit and it works. The only disappointment is that the sensitivity is very poor. Under ideal conditions (no wall) metal needs to be within less than 1 inch to be detected.
I would like to know if I can create a detector coil that would be capable of detecting metal 6-12 inches underground. I have looked at other designs and I am hoping that I can create a new larger detector coil and connect it to this unit. I am just confused about the role of the ferrous core for the coil. Other designs do not use a ferrous core so I am not sure if this would work. Could someone please advise as to whether this would be feasible?
Also, I would like to know if a strong rare earth magnet could be used to generate the magnetic field and then use a detector coil to detect the perturbation of the magnetic field due to the presence of metal.
Thank you.