The search coil is one of the most important parts of a metal detector.  Whereas the control box is considered the “brain” of the metal detector the coil might be considered the “eyes”.  The metal detector search coil sends out a radio wave at a certain frequency and receives it back. Different types of metal reflect the radio waves emitted by the coil differently, which is how metal detectors can find gold, silver, jewelry and other treasures underground.  Without the coil, the brains can’t “see” what is in the ground to tell control box, which in turn tells the user, what the underlying target may be. 

We stock metal detector coils for all major brands to sell both online and in our store.  We also have several different aftermarket search coils for metal detectors such as Coiltek, Detech, and the ever-popular Nel search coils. 

Two main variants of search coils are the concentric and the Double-D search coils: 

Concentric Search Coil 

The most widely used and economical metal detector search coil, the concentric coil which is preferred by many detectorists.  The concentric coil gives superior depth and a larger detection area in soils with low to moderate mineralization.  More heavily mineralized soil can “jam” a concentric coil and a Double-D metal detector coil may be preferred.  A larger coil generally means you get more depth.    Going too deep or too big with your search coil can lead to false positive signals in areas with a lot of mineralization or a lot of trash. A large coil may detect so much junk at one time that more valuable targets are missed.  If you face a situation where the ground holds a lot of trash in addition to good treasure, Sniper coils offer great detection in difficult situations. Their small detection field can help detectorists more easily pick through numerous targets. 

Double-D Coil 

The “DD” search coil is so named because of the shape of the two coils which overlap at the center unlike the traditional concentric coil where one coil lies inside the other.  This overlapping, and subsequent signal cancellation on certain areas of the coil, creates a unique shape to the field of detection. Instead of a bowl-shaped field of detection below the surface, the result is more of a knife-shape. As you wave the coil over the recovery site, you will get two distinct signals back-t- back as opposed to an erratic/jumpy signal. This is especially useful in very trashy areas. The only drawback is you have less of a detection field, and some argue that you lose depth with the DD. 

Once you’ve selected the right search coil for the ground you want to cover, a coil cover makes a great accessory. Your search coil is a vital component to your metal detector and keeping it in good shape is important for both its function as well as resale value. The best way to protect your search coil is to buy a metal detector coil cover. Search coil covers are inexpensive and cause zero interference when in use.