What Does a Metal Detector’s Search Coil Do?

search coil

The search coil of your metal detector allows you to better scan the ground for hidden treasures.

The finest metal detector in the world is no better than its search coil, so be sure not to overlook your search coil’s importance in treasure hunting. The type of search coil you use will determine how effectively your metal detector will perform the task at hand. What exactly is the search coil’s function? The search coil is mounted on the lower end of the detector’s stem. It takes power from the control housing through the search coil cable. Then, it transmits data between the metal detector and the ground. The search coil simply scans to allow the metal detector to find metal targets.

Most search coils operate with electromagnetic transmitter and receiver antennas embedded within the search coil. An invisible electromagnetic field is generated and picks up signals from the surface you’re scanning—soil, rock, water, sand, etc. Search coils designed by major manufacturers and provided with their detectors are generally reliable because they are maximized for performance. However, experts say there is no such thing as a standard search coil. A coil that operates perfectly in the park may not be suited for a pop-top filled beach. Search coils that find coins are not the same as those used to search for a treasure cache. There is also the issue of moisture and/or water-resistant capabilities. Find out if your search coil can resist a small amount of moisture, is waterproof for operating in heavy rainfall, or is fully submersible. Most coils made today fall into this last category of fully submersible.

Size Matters When it comes to Search Coils

Search coils come in many shapes and sizes. In general, the smaller the search coil, the smaller the object that can be detected. Larger search coils are designed to detect larger, deeper targets—but they can often locate small objects at deep depths, too. From small to large, search coils are designed with specific objectives in mind. Here is a snapshot of sizes & functions.

3-5″ Diameter: Very small search coils, also called “Snipers,” are ideal for trash-filled areas, allowing a detectorist to pinpoint coins in spite of nails and other junk. These search coils are able to maneuver in tight spots and around obstacles. They will signal at the detection of small and shallow targets. However, depth of detection is not as great as larger search coils.

7-9.5″ Diameter: This size search coil is what comes equipped with most detectors. 7-9″ search coils are usually the best for coin hunting and general purpose treasure hunting. These search coils are lightweight with a good scanning width and they are sensitive to a wide range of targets. Mid-range search coils offer decent depth of detection.

10-12″ Diameter and Larger: Large search coils are designed to detect coins and other targets at greater depths. Precise pinpointing is more difficult with the larger sizes because they pick up more mineralization. But these search coils are beneficial for finding, large relics and treasure caches. They provide considerable ground coverage, so you can cover a lot of ground more quickly than with a medium search coil.

Shop by Features for Search Coils at MetalDetector.com

MetalDetector.com stocks over 100 available optional search coils for just about every manufacturer’s detectors. To make it easier to narrow down your search results, you can Shop by “Features.” Choose from Brand, Search Coil Size, List Price, Search Coil Shape or Type, Audio Identification, Water Resistance, Country or Warranty. Daniel Bernzweig, of MetalDetector.com suggests, “To improve your understanding in all types of treasure hunting, I encourage you to learn about the various types of search coils and practice using them whenever possible.” Learn more about search coils in the Getting Started section of MetalDetector.com’s Learning Library: Choosing the Best Search Coil.