Metal Detectors FAQ

What do we mean by Motion and Non-Motion?

Motion detectors first started to arrive on the market in the early 1980's. Before this, all metal detectors were 'non-motion'. If you think of tuning a radio to your favourite radio station, you may occasionally have to re-tune it because it may have drifted off the station. This applies to non-motion detectors. As you scan the ground, the tuning may slightly drift from where originally set, but very easily brought back to the correct level. Motion metal detectors are self-tuning; once switched ON, they are continuously re-adjusting themselves for optimum operation. The metal detector search head has to be kept moving or scanning the ground in order to detect metal, the moment movement is stopped, metal detection stops, hence the word MOTION. The big advantage with this principle is that they are extremely simple to use and operate. Secondly, because of their sophisticated electronics, they are not affected as greatly by mineralised ground as non-motion metal detectors and therefore the penetratin is greater. Also better discrimination is achieved without significant loss of depth.

What Does The Discrimination Control Do?

The Discrimination control allows iron, silver paper and other rubbish items to be ignored by the metal detector, while still detecting gold, silver, copper and other non-ferrous metals. The higher the control is set, the more objects will be ignored. Be careful not to set it too high though, as you may find yourself rejecting good targets. For example when the control is set at maximum only the most conductive targets, copper and silver, will be detected. As gold jewellery is usually alloyed with a lower quality metal it would be rejected in this case. With experience you will learn the best place to set your discrimination control. When starting out we recommend you set it reasonably low, as it is better to dig a few trash items than to risk ignoring potentially valuable targets.

Why Is It Not Possible To Only Find Good Items?
Unfortunately a metal detector is not able to distinguish items as being 'worthless' or 'valuable'. It can however determine the conductivity of an object. Objects of low conductivity, such as iron, can easily be distinguished from a silver or copper object, which has high conductivity. The problem occurs in the so-called 'grey' area in-between. For example a 9-carat gold ring and a ring pull can appear very similar to a metal detector as they have a very similar conductivity.

What is Target ID?
Target ID is the metal detectors way of displaying the identity of a target in the form of a number. This complements the discrimination control by giving you the information the metal detector uses when it makes the decision whether or not an object should be detected. This allows you to determine accurately an objects conductivity, giving a strong clue as to its identity. On metal detectors with a discrimination control it was only possible to determine whether an object was more or less conductive than a chosen value. For example, if the discrimination control was set half way and an object was found, it would not be possible to tell whether it were a pound coin or a silver shilling. Target ID will give you this information as the shilling would be more conductive so a higher number would be displayed. This information is presented in two ways. Firstly a bar is shown when an object is detected. If the object is of low quality, iron or steel, only one or two segments will be shown. For a very good object, for example a silver shilling, the bar will fill up completely. This provides a very quick way of identifying the object. For more accurate identification, the Target ID number shows the point on the discrimination control at which each target would be rejected. As an example, a modern 5 pence piece would only just be rejected when the discrimination control is set somewhere between 50 and 60. When detected, the bar will fill up half way and the number '55' is shown.

How Deep Will A Viking Metal Detector Detect?
An obvious question, but one that can be difficult to answer. Firstly the larger the metal object is, then the deeper it will be detected, e.g. an old pre-decimal penny will be detected deeper than a new decimal penny, simply because it is a larger metal object. Secondly, the length of time the object has been in the ground the shape of the item and how it lies in the ground can have an effect. Rings or loop shaped objects lying parallel to the search head produce excellent results for detection. Thirdly, heavy mineralised ground can reduce the penetration of your detector. Taking all this into account and dependent on which VIKING model is used, single coins will be found anywhere between 10cm (4 inch) to 22.5cm (9 inch) with larger objects up to 1 metre (39 inch).

What Is The Purpose Of The Sensitivity Control?
The sensitivity control increases or decreases the metal detectors depth penetration in the Motion mode. Obviously, one wants to detect as deep as possible, but there may be times when the metal detector gives false signals or behaves in an erratic manner. This could be due to bad ground or some electrical interference from power lines or transmitters etc. In these circumstances, backing off the sensitivity level should help to achieve reliable operation.

Is A Viking Metal Detector Difficult To Operate?
Simple answer, NO. Our lower priced Non-Motion Metal Detectors are easily set or tuned to the correct level for correct operation. Our top of the range motion detectors are even easier, because of the more sophisticated electronics, automatically tunes the detector for you. Obviously all our metal detectors come with full operating instructions and remember our customer services are only a phone call away or email.

What Is Meant By Mineralisation Or Ground Effect?
The ground contains quantities of iron oxides of which some soils are more prolific than others. These oxides have built up over many centuries on land mainly worked and farmed by humans. Other land can contain magnetic iron oxides, which are naturally present in the ground. Metal detectors are affected by this ground mineralisation which is referred to as ground effect. Beaches also have an effect on the detector caused by the electrical conductivity of salt water.

Can You Use A Viking On The Beach As Well As Inland?

Using your metal detector on dry sand is exactly the same as using it on an inland site. However, wet sand is different, being known as conductive. Many thousands of non-motion metal detectors, like our Viking 1, 5 or 6DX2, have been used continuously on beaches with fantastic success. Some makes of powerful motion metal detectors are rendered useless on wet sand, because they give false signals or indications of metal, when there is nothing there. Our VK20 & 30 both feature a beach mode providing reliable performance on the beach.

What Does The Membrane Keypad Operate?
Featured on the VK40 the membrane keypad provides an alternative method of setting up the detector to the traditional rotary controls and switches. All the functions are controlled from the 5 keys provided. A single key press allows the detection mode to be selected, and the Discrimination, Sensitivity and Ground settings can be adjusted using a simple menu system.

What Does The Detector Display Show?

The Liquid Crystal Display provides a wealth of useful features. Target ID provides a visual indication of the target identity, and the display also shows at a glance which mode the detector is operating in. On the VK20 and VK30 the display shows the control setting as they are adjusted, and the VK40 features a larger display allowing the detector set-up menu to be used. The display also provides a continuous battery check.