LMS Metal Detecting - A Crash Course in Everything About Coils

           Whether you are just getting started or have been metal detecting for many years most of us are always looking for an edge-up with new better performing gear leading to a higher level of success. Introducing a new accessory coil into your setup could be just what you are looking for. While there are many options like size, shape, and type, your detector will determine the type that is compatible. However, you will have size and shape options that could greatly improve your metal detecting experience. There is no doubt some folks prefer a certain coil size/shape on any site and will resist change simply because they like it, and others might be more subject to change things up with a better option for the conditions at hand to possibly improve detecting productivity. However, with so many different coil types out there, it can be a daunting task to select the best one for you. Today we’ll take you through the different coil sizes, shapes and construction to help you pick the best one for you and your detecting sites.

SIZE

The size of a coil can influence the detection depth and sensitivity of a metal detector. A good rule of thumb is ‘the larger the coil, the more ground you can cover and the deeper it can go’. This sounds like the be all and end all, but the extra depth comes at a cost. Large coils have less sensitivity to smaller targets and a greater susceptibility to Electro Magnetic Interference (EMI), meaning you may have to notch that sensitivity right back down, depending on the interference of the location you hunting.

On the other hand, smaller coils have greater sensitivity to smaller, shallow targets and are less susceptible to EMI. There’s also the added benefit that small coils can fit in very confined areas. Of course the cost here is the coverage on each swing has decreased in size meaning it might be easier to miss a good target.

For coin and treasure detecting, the larger coils are best where you want to cover large areas quickly, where smaller coils are great if you’re in areas with lots of shallow targets mixed in close proximity with undesirable iron targets.

For gold detecting, generally you will be in remote areas that have little to no EMI, so a large coil will give you more ground coverage with maximum sensitivity and depth. While smaller coils will provide increased sensitivity to small nuggets close to the surface.

SHAPE

Coil shape can be an important factor. Circular coils are the most common because they are stable and offer the best performance, while different, non-circular shapes are used where there is a need to conform to a particular physical requirement.

Elliptical coils are easier to maneuver around bushes or between rocks, while still covering the same amount of ground as a circular coil of the same size.

Open web coils are lighter and reduce drag for aquatic hunters to pass through water.

COIL CONFIGURATION

The Monoloop coil features a single winding around the outside of the housing that both transmits (Tx) and receives (Rx) signals, producing a large cone shaped pattern and typically giving the best depth. Although the Monoloop coil can provide better depth than the Double-D, the monoloop can be more difficult to ground balance in heavily mineralized soils where the Double-D reins supreme.

Smart Coils

Smart coils contain circuitry that interacts with the detectors control box, unlocking  many advantages for the user. The early smart coils would change the Tx frequency of the detector, enhancing it for various detection scenarios like gold fields and beach detecting while still being an excellent treasure detector.