Things To Consider Before Buying A Gold Detector
Metal detectors work by transmitting an electromagnetic field from the search coil into the ground. Any metal objects (targets) within the electromagnetic field will become energized and retransmit an electromagnetic field of their own. The detector’s search coil receives the retransmitted field and alerts the user by producing a target response. metal detectors are capable of discriminating between different target types and can be set to ignore unwanted targets.
The basic concept of how a metal detector works is quite simple. It sends out an electromagnetic signal, and if anything bounces back, the detector measures its estimated size and structure. Radar works similarly. Bats do the same thing with sound to identify obstacles and food.
The tricky bit is interpreting the reflected signal accurately, so you don’t spend all day digging up rusty soda cans or bottle caps. There are several specific features to consider.
Generally speaking, the larger the coil, the deeper the electromagnetic signal will penetrate. Our best metal detector for kids has a 6.5-inch coil and can pick out coins at around 4 inches deep. Our top pick has an 11-inch coil and will reach down 12 inches or more.
Also, check if the coil is waterproof. Ideally, it should be IP (Ingress Protection) rated, but some manufacturers do not use this independent testing because of the cost involved. Some metal detectors are described as weatherproof, but this offers no specific guarantee, and it’s unlikely they could be submerged without damage.
Frequency and Sensitivity
Most consumer metal detectors use VLF (very low frequency) transmitters. The frequency available might be anywhere from 5 kHz (kilohertz) to 40 kHz, with 5 to 15 kHz considered the sweet spot for consumer models. Most machines are fixed, though some offer multiple settings. The latter allows sensitivity to be adjusted to suit conditions, and the materials or items being searched for.
A low frequency is good for finding conductive metals like silver (and thus some jewelry), and has good depth penetration. However, because not many electromagnetic waves are transmitted it isn’t so good for small items. Higher frequencies are better for gold, iron, and coins, but the waves often don’t go as deep.
There can also be problems with interference from minerals in the ground. A feature called Ground Balance is often incorporated to solve this problem. Many metal detectors also offer multiple modes like beach, park, or field, for example, to help compensate for ground conditions.
It’s nice to be able to tell the difference between junk and treasure before going through the effort of digging it up. When metal detecting, this is called discrimination. All metal detectors try to help with identification to some extent and provide controls to narrow down the type of target. This is often called “notch discrimination” or “notching out,” which tells the metal detector not to look for items within certain frequency ranges.
There is always a visual display of some kind, and usually an audio signal (called threshold or threshold pitch). The best metal detectors also offer a target ID and estimate target volume (size).
Weight and Ergonomics
Handheld metal detectors are all reasonably light, but most people will notice a big difference between a 2-pound model and a 4-pound machine if it’s being used all day.
Some handles are padded, some not. A forearm/elbow support is usually provided. Shaft length is often adjustable to accommodate people of different heights, but for those who fall outside the ‘average,’ this is another feature worth checking.
All metal detectors use batteries. They can be as simple as a couple of AA or 9-volt cells (often not included), or they can be sealed rechargeable units. While the latter will usually last several years, replacement may mean returning it to the manufacturer to avoid damaging waterproof seals. When you’re ready to upgrade, find out how to recycle electronics.