Metal detecting can be divided into two main areas: - gold prospecting and coin, jewellery & relic hunting, with a subdivision of this being underwater detecting. There are also a couple of models that are intentionally designed to be very versatile and can be used for either purpose. To get the best detector for your needs, you need to determine which area most appeals to you. If you are able to decide on one type or the other, you will be able to buy a highly specialised detector, designed with the features you specifically require.

Gold prospecting detectors tend to have excellent ground balancing abilities and are often stronger in depth and sensitivity than the coin hunting models, but they generally lack discrimination. Coin & treasure hunting detectors feature advanced and accurate discrimination and target identification abilities, but may not cope well in heavily mineralised ground. Therefore, there is a trade off in performance and features and your detector should have the abilities that you'll find useful for the area of detecting you intend to spend most of your time in.

When comparing different metal detector models to determine which to buy, there are four main characteristics that can be used to categorise how one detector compares with another. These are: - Depth; Sensitivity; Discrimination and Ground Balance. Other factors that should be considered are the size and types of coils available, what batteries are used and how long they last, and of course, the price of the detector.

We have prepared this short explanation in an attempt to simplify some of the differences, so you can better understand which detector will suit your needs.

Depth

This refers to the distance that a metal detector can penetrate and detect metal objects into the ground. Often, some detectors produce extraordinary distances when demonstrated in the air but are quite disappointing when the target is buried in the ground.

The depth attained can be influenced by factors such as the frequency of the detector's electro-magnetic field, how sophisticated its circuitry is, how well it will cope with mineralised soils, how stable and quiet the detector operates, how large the target is, etc.

Depth is often affected by the frequency of the detector. Low frequencies will tend to provide improved depths and high frequencies will normally improve sensitivity, but at less depth. Since its inception, Minelab has made tremendous advances in metal detecting technology. With the use of microprocessors, high-tech surface mount circuitry and innovative technology, Minelab has evolved to give greater depth, improved sensitivity and superior performance. A huge advantage was the invention of MPS (Multi-period sensing) technology and then DVT (Dual-voltage technology), which combined, can search far deeper than any other conventional detector, while still having the sensitivity to equal the best of the single high frequency detectors.

Sensitivity

Often, especially when gold prospecting, it can be desirable to find very small size objects. Sensitivity to find small targets is determined by the detector's frequency. Models like the Explorer SE, Quattro and Sovereign GT operate in a wide range of frequencies at the same time and the X-Terra series can change frequency by swapping coils.

Discrimination

This is the function of some detectors to determine what type of metal has been detected before digging it up. This is a great time saver for treasure hunters with some discrimination systems being highly accurate. Detectors with Notch discrimination enable the operator to cancel out unwanted metals while still accepting desirable items. Most discrimination systems operate by testing the target's conductivity level and producing an estimate of the target's identity. Notch discrimination segments the full conductivity range of metals, allowing the operator to accept only those segments that are desirable. The more notches available in the detector, the more accurate the discrimination will be.
The Explorer SE has the ultimate in discrimination systems, which tests the metal target for not one, but two characteristics. By testing for two factors, even targets that have similar conductivities can be separated.

Discrimination is not advisable when searching for native gold nuggets, as impurities in gold, as well as concentrated minerals in the soil around the nugget may confuse the discriminator, resulting in a false reading. For this reason, most metal detectors designed for gold prospecting have limited discrimination ability.

Ground Balance

For gold prospecting, this is probably the most important function on the metal detector and is often the one overlooked when comparing capabilities of each detector. Ground balancing is setting the detector so it can compensate for the effect minerals in the ground will have on the machine. This allows it to scan the ground and only provide a signal when it passes over a target. If this is not done properly, the detector will produce false noises from the ground itself and you will find it very difficult to tell the difference between ground noise and a metal target.

All metal detectors come with ground balance of some sort, some can be manually adjusted, some are factory pre-set and others are a true automatic tracking where the detector is testing the ground effect continuously and alters the ground balance setting to suit. Metal detectors with true automatic tracking excel in highly mineralised soil areas, as their ability to compensate every few seconds makes them so much easier to use and more efficient.

In conclusion, we would recommend that you consider the main purpose you wish to use the metal detector for (ie. Gold prospecting, hunting coins in parks or around old buildings, or looking for lost jewellery on the beach), then consider what each machine has to offer to suit that purpose and the functions that will be important to you.

Ultimately the choice is yours and we hope this information assists you in choosing the right detector for your needs. Please feel free to contact us for advice or visit your local detector shop to see what they suggest for the local area.