What Does Discrimination Mean on a Metal Detector?

 

Understanding the Concept of Discrimination in Metal Detection

In metal detecting, discrimination means the ability of a metal detector to distinguish between desirable and undesirable metals. For instance, metal detectors work by sending an electromagnetic field into the ground and analyzing the returned signals, which vary based on the conductivity of metals.

Discrimination settings allow detectorists to ignore some metals, like aluminum pull tabs, while focusing on targets with high conductivity, such as gold or silver.

The Importance of Discrimination in Metal Detecting

Using the discrimination setting enhances efficiency during metal detecting by reducing the chances of digging up unwanted items.

For those new to the hobby, understanding how discrimination works can improve their success rates by helping them set discrimination to find desirable targets.

This setting is particularly useful when metal detecting in areas with lots of trash, as it enables detectorists to focus on higher-value targets based on their conductivity and other distinguishing features.

Using Discrimination Charts to Identify Gold vs. Iron

Discrimination charts categorize common metal types by their target ID range and conductivity, helping detectorists set their discrimination accurately for efficient metal detecting.

For instance, valuable metals like gold nuggets often appear in higher conductivity ranges, while ferrous metals like iron are lower. By consulting a discrimination chart, users can set their detectors to focus on good targets without missing desirable finds.

A Guide of signals chart

Gold and iron produce different responses on a metal detector, thanks to their contrasting conductivity levels.

Gold has high conductivity, resulting in a more consistent and clear signal. Iron, however, is a ferrous metal that can create erratic signals due to its lower conductivity and variable response in mineralized soil.

Metal detectorists can leverage discrimination settings to prioritize gold nuggets and ignore certain types of iron items, thereby focusing on targets worth digging.

How Do Metal Detectors Discriminate? Mechanism and Settings

Metal detectors use advanced technology to identify and filter specific types of objects based on their conductivity. The discrimination setting on a metal detector, often labeled as “disc,” helps detectorists control how much discrimination to apply to different targets, enabling the detector to "accept or reject" metals based on their conductive properties.

There are four main types of discrimination in professional Metal detectors:

• Variable discrimination – The simplest type of discrimination that uses a control knob to adjust the level of discrimination.

• Iron Mask/Iron Reject – Used mostly with gold prospecting detectors to ignore iron junk.

• Notch discrimination – Allows specific target types to be accepted or rejected.

• Smartfind – The most advanced form of discrimination. Target IDs are plotted based on both ferrous and conductive properties on a two-dimensional (2D) display. Individual segments or larger areas of the display can be shaded to reject unwanted targets.

Mechanism of Discrimination in Detectors

The mechanism of discrimination relies on the metal detector’s ability to recognize the electromagnetic properties of various metals. As the transmit coil sends an electromagnetic field into the ground, the detector measures the strength of the signal returned by each metal target.

Certain metals produce unique responses, allowing the detector to identify the metal type in the ground. For example, ferrous metals like iron create a distinct response compared to more conductive metals like gold or silver.

Adjusting Discrimination for Optimal Detection

Adjusting the discrimination settings on a metal detector affects how the detector can pick up different targets. Higher discrimination will ignore certain types of metals, such as trash or iron, while lower discrimination increases the chances of detecting a wider range of objects. When setting discrimination levels, users should consider the conductivity of metals they want to detect.

For instance, setting discrimination too high may cause the detector to miss certain valuable targets, like small gold nuggets with lower conductivity. Minelab detectors, for example, offer discrimination settings that are easy to adjust for both beginners and seasoned detectorists, helping them locate the most desirable target types.

Adjusting Sensitivity Based on Discrimination Levels

When adjusting sensitivity based on discrimination, it’s essential to find a balance between the two settings. For instance, ground mineralization can interfere with sensitivity, causing detectors to produce false signals if set too high.

By adjusting both sensitivity and discrimination levels, detectorists can better focus on metal objects worth digging. VLF (Very Low Frequency) detectors are known for their adjustable sensitivity, making them suitable for wet beach sand and mineral-rich soils.

Difference Between Metal Detector Discrimination and Sensitivity?

Discrimination and sensitivity are essential yet distinct features on a metal detector. While discrimination helps users ignore certain metals based on their conductivity, sensitivity refers to the detector’s capacity to detect metals at greater depths or of smaller sizes.

Understanding the difference can significantly improve a detectorist’s experience in targeting desired metal objects.

Discrimination vs. Sensitivity: Key Differences

Discrimination and sensitivity differ in how they impact the detection process. 

Sensitivity stricly relates to the strength of the signal a detector emits, which influences how deep the metal detector can detect. High sensitivity allows users to identify deeper targets, but it can also lead to more false signals in areas with high ground mineralization.

 Let's see an example with the signal theory.

How Discrimination Affects Detection

Adjusting discrimination can change what a detector recognizes. For instance, zero discrimination allows the detector to find all types of objects, while higher levels of discrimination will ignore metals with low conductivity.

Some types of discrimination, such as notch discrimination, let detectorists specifically reject certain metals, like aluminum, without affecting the detection of other targets. Notch discrimination can be especially helpful in areas where certain target types, like aluminum pull tabs, are common and unwanted.

Why Discrimination Chart is Important for Metal Detectors

A discrimination chart helps detectorists differentiate between high-value targets like gold and less desirable metals like iron. These charts display the typical responses of different metals based on conductivity and target ID ranges, guiding users on the optimal discrimination settings to use when targeting specific metals.

Our recommendations

Discrimination in metal detecting enables users to focus on specific metals, filtering out unwanted items and improving search efficiency.

By adjusting discrimination and sensitivity settings, detectorists can optimize for their environment and targets, like prioritizing gold over iron.

Understanding conductivity and using discrimination charts further enhance detection, making searches more precise and rewarding for both hobbyists and professionals.