The Best Coil Type for your Metal Detector

Metal detectors come with a variety of coil sizes and types. Some detectors are designed to work with one specific coil, while others have multiple coils available that you can interchange. The main types of coils are Concentric, Elliptical, and Double D coils. Each work a little differently and have different advantages and disadvantages.


Concentric Coil

Concentric coils are round shaped. They transmit a cone shaped signal into the ground that reaches deepest in the center of the coil. When using this type of coil you should overlap your swings in order to maximize the depth that you find items. If you don’t, you will likely miss many targets.


  • Pinpointing is easiest because the strongest signal is always at the center of the coil.
  • Discrimination works best with concentric coils.


  • Are less stable when they are affected by ground mineralization and salt water.

Concentric Metal Detector Coil

Elliptical Coil

These are similar to concentric coils except that instead of being round they are oval shaped. By making the coil longer front to back and shorter side to side, you have a coil with the same area as a concentric coil but that will cover more ground with each sweep of the coil. Like the concentric coil, the signal reaches the deepest in the center of the coil so you should overlap you swings to achieve maximum depth.


  • Covers more ground with each sweep than a concentric coil of the same size.


  • Pinpointing is somewhat more difficult to learn than with a concentric coil, but still easier than with a Double D coil.
  • Are less stable when they are affected by ground mineralization and salt water.

Elliptical Metal Detector Coil

Double D Coil

The Double D coil had two “D” shaped halves to the coil. This results in a more flat and square shaped signal being sent into the ground.


  • It doesn’t require the overlapping swings needed by concentric and elliptical coils because the signal is more square than cone shaped.
  • It is less affected by ground mineralization since the field is flat.
  • Since the signal is more flat, it is better at separating between two objects that are close together in the ground.


  • Pinpointing is most difficult with this type of coil.
  • Discrimination does work quite as well as with the other coils.Double D Metal Detector Coil