Fisher Metal Detecting Coils

What are the Different Types of Search Coils?

There are several different types of metal detector coils you can choose from.

• - Mono
• - 2-Box
• - Imaging
• - Double-D
• - Concentric

When choosing, you should consider what type of soils you intend to search, what type of detector you have, and what type of target you are searching for. There are five basic types of search coils: concentric, imaging, mono, double D, and 2-box coils.

Mono search coils are used only with pulse induction metal detectors. They work the same way as the above coils but are different in that the transmitter and receiver are located together within one coil. Mono coils enable you to have maximum sensitivity and depth but may be more difficult to use in highly mineralized soils.

2-box coils are unlike the above coils as they involve a transmitter and receiver coil that are at opposite ends of the detector, up to a few feet apart. This distance between the coils widens and deepens the detection field, making it easier to find deeply buried targets.

Imaging search coils are a type of concentric coil that are more advanced. They have an additional receiver coil, which allows for true target sizing and additional depth capabilities. This will allow you to distinguish between trash and treasure more effectively.

Double D search coils, called this because they are shaped like back-to-back letter Ds, are designed to reduce ground interference and improve performance. Because of the way DD coils are shaped, they have a cancelling effect on ground signals. This makes them more effective in areas with mineralized ground. This type of coil is often preferred for relic hunting.

Concentric search coils are the most common type of coil. This type of coil is called concentric because it consists of two coils, one inside the other, like concentric circles. The outside coil is the transmitter and the inside coil is the receiver. Concentric search coils are versatile and provide the most symmetrical field, making it easy and consistent when narrowing in on targets.

What are the Different Sizes of Search Coils?

Using different size search coils can improve your metal detecting performance in different areas. The difference in coil sizes can mean more ground coverage and deeper detection rates. It’s generally accepted that the diameter of the coil you use is an estimate of its detection depth for targets that are about the size of a coin – although this isn’t always a guarantee. Smaller coils have a more concentrated magnetic fields in smaller areas. They tend to work well in areas that have more metal debris. Due to the smaller size, it may take you longer to detect the area you are searching, but it also may enable you to detect multiple targets that are in close proximity to one another.

Larger coils, of course, will make it easier to detect larger search areas, but it can lead to your search being less concentrated which may cause you to miss smaller targets. If there are many metal items inside the coils field, it may be harder to pinpoint specific targets.

Does the Shape of the Search Coil Matter?

Search coils come in different shapes as well as sizes, and the shape will provide you with different benefits depending on where you are hunting. For example, an elliptical coil offers a lot of flexibility and with a narrower width, it can provide better coverage of your search area. A round or circular coil will provide more sensitivity and greater depth in detection areas. If you have further questions about which type of coil to use for a specific search area, ask one of our knowledgeable employees for advice.