Metal Detector Types

Waterproof, coin hunting, prospecting and other types of metal detectors...

Metal detectors are available in various types, from the most basic to very sophisticated models. While all metal detectors use electromagnetic induction, they can vary in their capabilities and specialties. The basic models are the easiest to use, but limited in their technological features. The sophisticated metal detectors have more features and buttons which increases their capabilities, but is also makes them more complicated to operate and requires more practice to use them proficiently.

Choosing A Metal Detector

Before buying a metal detector, you should decide what type of metal detecting you want to do. Metal detectors have different features, technologies, and performance capabilities based on their intended use. There are hobby metal detectors, industrial metal detectors, and security metal detectors (walk thru and handheld scanners).

For those interested in metal detectors for treasure hunting and recreational use there are basically four categories of use:

• General Use Metal Detecting - looking for coins, relics, and other buried treasures
• Gold Prospecting - looking for gold and gold nuggets
• Underwater Metal Detecting and Beaches/Salty Water - use waterproof metal detectors
• Cache Hunting and Deep Searching - looking for larger treasures that were buried and hidden and not just lost or misplaced, treasure caches are usually deeply buried

While some metal detectors are good choices for all around general searching for coins, relics, and other hidden treasures, some metal detectors are designed for specialized uses. Metal detectors designed for gold prospecting are capable of detecting small pieces of gold, but do not discriminate (ignore junk metal) as well as general purpose metal detectors. And while metal detectors used for general types of treasure hunting are superior in their discriminating capabilities, they are not designed to detect very small pieces of metal like gold prospecting metal detectors. Some metal detectors are specialized for deep searching and others are designed for underwater use.

Because of the varying capabilities of metal detectors, there are many things to consider before buying one. It is important to consider the type of metal detecting you want to do, what features are important to you, how much money you want to spend, and what type of terrain and/or water areas you will be searching. It is also important to find a metal detector that is comfortable to use for long periods of time - not too heavy and a comfortable position for your hand.

Using a Metal Detector

Operating a metal detector is as simple as turning it on and slowly moving the search coil back and forth over the search area about two to three inches off the ground. When the metal detector passes over a metal object, it makes an audible signal. The more sophisticated metal detectors have displays which identifies the type of metal and how deep it is buried. Many metal detectors are also capable of discrimination, the ability to selectively reject specific metal or junk items.

Metal detectors may vary in features and capabilities, but most of them have the same four basic parts:

• Stabilizer - helps stabilize the metal detector as you sweep it back and forth by supporting the forearm, usually a oval or half circle near the hand grip area
• System Control Box - the part of the metal detector that holds the circuitry, control knobs, batteries, microprocessor, and other system controls
• Shaft - the long tube that attaches the system control pack to the search coil, usually adjustable to accommodate a persons height
• Search Coil - the flat circular part that is used to scan directly above the search area and detects the metal, also called loop, antenna, or search head

Some metal detectors also have LCD display screens and most have a jack for connecting headphones. While using a metal detector is fairly simple, it takes practice to become proficient, especially on the more sophisticated models.

Metal Detectors and Depth of Search Area

Metal detectors are helpful in finding buried metal objects, but they can usually only detect items within eight to twelve inches from the surface. The exact depth that items can be detected varies on several factors, including the type of metal detector, the type of metal in the item, the size of the item, the type of soil, and interference from other objects.

There are basically three types of metal detector technologies:

• VLF-Very Low Frequency - a high-end technology and the most widely used technology for metal detectors, effective at discrimination (able to differentiate between various types of metal), good for treasure hunting of items such as coins, relics, and jewelry
• PI-Pulse Induction - similar to radar technology, not very effective in differentiating between various metals, widely used in industrial applications, such as construction to locate hidden pipes and wires, also effective in salt-water and for scuba diving and for deep searching and cache hunting
• BFO-Beat Frequency Oscillation - basic technology that works like radar, is the cheapest and easiest technology to make, but also not as effective as PI or VLF technology

The benefits of VLF metal detectors are their ability to discriminate and ignore junk metal. The benefits of PI metal detectors are their effectiveness in salt water and for detecting metal at deeper depths. The benefit of BFO metal detectors is simply that they are cheap to buy and easy to make.