Metal detectors are mechanical devices used to locate different types of metal that have been buried or discarded. They are also used for security purposes in airports and various institutes across the world. There are a number of features buyers should look for when searching for a metal detector, and the following guide shall examine the 7 most helpful. This guide will also detail on how to find a suitable metal detector on eBay, as the site has a large selection of new and used devices for sale at lower prices.
7 Metal Detector Features
1 – Sensitivity
The sensitivity of a metal detector determines what it should be used to detect. A detector with high operating frequencies is suitable to use to find light metal, or items located in the topsoil. Those with lower operating frequencies can penetrate deeper into the ground, and are used to locate bigger pieces. Buyers interested in metal detectors used for finding gold should search for those with a frequency of between 6.4kHz and 20kHz. The sensitivity control on a metal detector should be adjusted appropriately to varying conditions. Buyers should consider the density and mineral composition of the ground, the presence of power transformers and the metal they are searching for. Information regarding sensitivity control can be found in the operating manual, and buyers are advised to read this before using.
2 – Discrimination
This feature is found on the majority of modern metal detectors, and buyers should avoid models that do not have it. Discrimination is the ability to differentiate between metals, and is a very useful tool. Metals produce individual magnetic responses, and detectors with discrimination can identify these responses. The level of discrimination varies from model to model, and buyers should compare these levels when browsing for a device. This feature can raise the price of a detector.
3 – Calibration
This feature is also known as ground balance, and is responsible for accounting for the various metallic minerals present in all soil. Detectors with low calibration are more prone to interference from outside signals. However, the majority of modern devices have reasonably good calibration strength, and the levels are adjusted through the control box.
Buyers should find instructions regarding calibration in the detector’s operating manual, and the device should be properly calibrated every time it is used on a new soil. Smaller handheld detectors used for security screenings often have automatic calibration, and this helps the detector adjust to different materials.
4 – Radar
Metal detectors with ground penetrating radar are able to determine the size and density of a metallic object. This feature can really speed up the searching process, and is often used by expert treasure hunters. The detail of the reading and the sophistication of the technology will increase price, so this feature is only recommended for more experience users.
5 – Coil Size and Shape
The shape and size of a coil determines the depth and range the device’s electromagnetic waves can reach. Concentric coils are the standard shape, and have a penetrative depth of about twelve inches. Spider coils have a similar range to the concentric models, but are more sturdy and ideal for use in thick undergrowth. Elliptical coils also have a penetrative depth of twelve inches, but the oval design of the coils results in greater ground cover. Double D coils have the greatest range of all, but do not penetrate as deep as the others.
It’s important to think about where the detector will be used as the soil type and density will affect how well the coil works. For example, a double d coil would be ideal for use on a beach, as sand is loose and can be penetrated easier, whereas it will have a much shorter depth on dry and hard soil.
6 – Metal Detector Technology
There are three different types of technology used in metal detectors, and these are BFO, VLF, and PI.
· BFO stands for beat frequency oscillation, and is the simplest and least expensive option. BFO detectors use two coils and an oscillator to create a set frequency that changes in the presence of metal. Buyers should note that this technology is prone to outside interference, and this form of detector is more suitable for beginners.
· VLF stands for very low frequency, and is a common technology used in detectors today. VLF works by emitting a low frequency magnetic field into the ground and picking up reflections. VLF allows the user to tune the magnetic field, so only certain metals are picked up.
· PI stands for pulse induction, and treasure hunters looking for items deep below the surface use detectors with this technology. PI detectors use a single coil to send and receive a pulse, and can pinpoint how far below the surface an item is. These detectors are more expensive than those with VLF, but are far more advanced.
7 – Pinpoint Mode and Depth Indicator
These are two separate features but are often included together in the mid level detectors. Pinpoint mode automatically aligns the response point to the centre of the coil, resulting in a precise location of objects. Depth indicator informs the user how far down they have to dig to find the object. The information for both of these features is usually found on an LCD display in the control box.
Buying Metal Detectors on eBay
As previously mentioned eBay has a large selection of new and used metal detectors for sale at more affordable prices than those sold in DIY stores. To find a suitable device, take the following simple steps.
· This will load the Metal Detectors listing page, and from here buyers can begin to search for a desired model. The easiest way to do this is to type the name of a brand or feature into the search bar and press enter e.g. PI Metal Detector.
· The Condition filter allows buyers to list new or used detectors only. Buyers interested in browsing for used models should always check the ‘Description’ box on the item page for specific details about the device’s condition.
eBay Deals has a number of electronic products for sale at reduced prices, and it’s a good idea for buyers to check here for detectors before placing any bids. This section of the site can be accessed by clicking on the Deals link at the top of the page, followed by the Electronics title.
Metal detectors are used for a variety of purposes including archaeology, security, and amateur treasure hunting. Buyers should be aware of the above 7 features, and should try to purchase a detector with as many as possible. However, it’s important for buyers to consider the type of soil the detector will be used on, and what it is they are trying to locate. This should influence the type of coil used, and the technology the device employs to detect metal. Buyers will find that used detectors are sold at much lower prices, but it’s important to ensure that the device is in working order and has no damaged parts.