Various challenges for metal detectors including wet soil and buried power lines.

Why Understanding Detection Factors is Crucial

Whether you’re a seasoned professional or just starting your metal detecting journey, learning the various factors influencing detection can significantly improve your experience. These elements can make or break your detecting session, especially when you’re in a new terrain or seeking specific targets. By learning these nuances, you can understand when to adjust your settings, adapt your techniques, and as a result, significantly improving your chances of unearthing valuable finds. Let’s dive right in.

The Impacts of Target Size and Depth

As all metal detecting enthusiasts come to learn the hard way, not all targets are created equal. While the target’s material will impact our signal i.d., the size, and depth of a target can significantly influence its detection as well. In this segment, we’ll delve into the relationship between target size and depth, and how these factors play a pivotal role in our treasure-hunting efforts.

The Intricate Dance of Size and Depth

At the heart of metal detecting lies a simple truth: the size of a target and its depth in the ground are intertwined. Larger objects can generally be detected at greater depths than smaller ones. Conversely, smaller objects, while often closer to the surface, can be trickier to pick up due to their size.

Factors Influencing Target Detection

Several elements come into play when detecting objects of varying sizes and depths:

Metal Type and Conductivity

Different metals have distinct conductivity levels. For instance, a large iron relic will be easier to detect than a natural gold picker, even if the speck of gold is closer to the surface.

Detector Search Coil Size and Type

The search coil is your detector’s “eye,” and its size can influence what it sees. Larger coils can detect deeper targets but might miss smaller objects close to the surface. Smaller coils, on the other hand, offer precision but might not reach deeper targets.

The Frequency of Your Metal Detector

How Frequency Impacts Depth
Low Frequencies

These can penetrate deeper into the ground, making them ideal for detecting larger objects buried at significant depths. However, they might be less sensitive to surface-level small items.

High Frequencies

While they’re adept at detecting small objects on or near the surface, their depth penetration might be limited compared to low-frequency detectors.

How Frequency Impacts Detecting Based on Target Size
Low Frequencies (1-15 kHz)

Detectors operating at lower frequencies are more sensitive to larger objects. They can detect larger relics, coins, and jewelry at greater depths. However, they might not be as effective in detecting tiny objects, such as small gold nuggets.

High Frequencies (15-40 kHz and above) 

High-frequency detectors excel at finding small objects, especially gold nuggets. They offer better sensitivity for tiny items but might not penetrate as deeply as their low-frequency counterparts.

How to Adjust for Target Size and Depth Issues

With the challenges of size and depth in mind, here are some techniques to enhance your detecting prowess:

Using Different Coil Sizes

If you’re in an area where you suspect both deep, large objects and shallow, smaller ones, consider switching between large and small coils. This way, you can ensure a comprehensive search.


This technique involves moving your detector in a tight pattern over a suspected target to determine its exact location. It’s especially useful for locating smaller items.

Adjusting Frequency for Optimal Detection

Many modern metal detectors come with adjustable or multi-frequency options, allowing users to switch frequencies based on the terrain and the type of objects they’re seeking. By understanding the relationship between frequency, object size, and depth, detectorists can adjust their equipment to maximize their chances of making valuable finds.

Use a simultaneous multifrequency metal detector

Modern, advanced metal detectors are now leveraging simultaneous multifrequency. This technology ensures a broad range of coverage to better pick up small and large objects, regardless of their depth. By combining the depth advantages of low frequencies with the surface sensitivity of high frequencies, these detectors excel without advanced knowledge and manual adjustments.

Ground Mineralization: What is the soil or sand made of?

What is Ground Mineralization?

Ground mineralization refers to the natural minerals present in the ground, which can interfere with a metal detector’s ability to locate and identify buried metallic objects. These minerals can produce signals that the detector picks up, often leading to false positives or masking the presence of actual targets.

If you would like to learn more about ground mineralization, I’ve covered it in detail in the “Understanding Soil Mineralization” article.

How Mineralization Affects Metal Detection

Mineralized grounds can be a metal detectorist’s nightmare. Here’s why:

Inaccurate Target Identification

Ground mineralization can interfere with a detector’s ability to correctly identify the type and size of a buried object. This can cause inconsistencies in the target ID displayed by your metal detector.

False Signals

The minerals in the soil can produce signals that mimic those of actual metallic targets, leading to wasted time and energy.

Reduced Detection Depth

High mineralization can decrease the depth at which a detector can locate objects, making deeper targets harder to find.

Decreased Sensitivity

Mineralized grounds can reduce a detector’s sensitivity, making it harder to detect smaller or less conductive targets.

Increased Noise

The constant chatter or noise from mineralized ground can make it challenging to distinguish between genuine signals and ground feedback.

Techniques to Overcome Mineralized Ground

Fret not! With the right approach, you can still find success in mineralized terrains:

Ground Balancing

This feature, found in many modern detectors, allows the device to “ignore” the minerals in the soil, focusing solely on metallic objects. Regularly ground balancing your detector is crucial in highly mineralized areas.

Frequency Adjustments

Some detectors allow users to change frequencies. Opting for a lower frequency can help reduce the effects of mineralization, though it might also reduce sensitivity to smaller objects.

Use a Simultaneous Multifrequency Metal Detector

Not all detectors are created equal. Some are more susceptible to mineralization interference, while others come equipped with features to combat these challenges. A simultaneous multifrequency metal detector provides a wide range of coverage and deeper penetration in difficult soil conditions.

Noise Cancellation 

Noise cancellation in metal detectors is specifically designed to counteract the erratic signals and disturbances caused by mineralized soils. By filtering out the “noise” or unwanted signals from the ground, this feature helps the detectorist to better recognize true target signals. This results in a less headache-inducing detection experience, reducing the chances of being misled by the ground’s mineral content.

Iron Audio

Ground mineralization can sometimes amplify signals from ferrous (iron-containing) items, making them appear more valuable than they truly are. The iron audio feature becomes invaluable in such scenarios. It allows detectorists to audibly identify and differentiate iron targets from more valuable finds easily, even in mineralized soils. By providing a distinct audio tone for iron, users can quickly discern and potentially ignore unwanted iron signals, ensuring that their detecting efforts remain concentrated on more promising targets.

Electromagnetic Interference (EMI): The Man-Made Nuisance

In the world of metal detecting, not all signals lead to buried treasures. Sometimes, they’re just distractions caused by Electromagnetic Interference (EMI). But what is EMI, and how can you minimize its effects to ensure a successful hunt? Let’s dive deep into the world of electromagnetic disturbances and discover how to tackle them effectively.

Decoding EMI: The Unseen Disruptor

Electromagnetic Interference, commonly known as EMI, refers to external signals that can interfere with your metal detector’s operation. These signals can originate from various sources and can lead to false readings, making it challenging to distinguish between genuine finds and mere disturbances.

Common Culprits of EMI

The modern world is buzzing with electronic activity, and some of these can be sources of EMI:

Utility Lines

Utility lines, often seen crisscrossing our landscapes, are essential conduits for transmitting electricity across vast distances. These high-voltage lines are not just physical entities; they are also powerhouses of electromagnetic activity. As electricity flows through them, they emit strong electromagnetic fields that radiate outward. For the unsuspecting metal detectorist, these fields can be a significant source of interference, especially when detecting in close proximity to these lines.

Personal Electronic Devices

In our digitally connected age, we’re surrounded by a myriad of electronic devices, many of which we carry with us daily. However, these devices continuously transmit and receive signals, creating a web of electromagnetic activity. When metal detecting, the proximity of a smartphone can inadvertently introduce interference, leading to unclear or false signals on the detector. Being aware of these potential sources of interference and taking steps to minimize their impact, such as turning off unnecessary devices or maintaining distance from other detectors, can ensure a more accurate and fruitful detecting session.

Other Metal Detectors

It’s not just personal gadgets that pose a challenge. If you’re detecting in a group, other metal detectors operating nearby can interfere with each other, especially if they’re on the same frequency.

The Impact of EMI on Metal Detection

EMI can pose several challenges for detectorists:

False Signals

Electromagnetic Interference (EMI) can be a major culprit behind false signals in metal detecting. As external electromagnetic waves intersect with those of the detector, they can produce readings that mix in with the reading of genuine metallic targets. Unlike the false signals created by ground mineralization which often creates steady targets that are false signals, the false signals from EMI will fluctuate even when the metal detector is held steady or sitting stationary on the ground.

Reduced Sensitivity

EMI can also dampen a detector’s sensitivity, making it less responsive to genuine metallic objects. High levels of interference can overshadow weaker signals from smaller or deeper targets. This reduced sensitivity means that valuable finds might go unnoticed, even if they’re within the detector’s range.

Difficulty in Ground Balancing

Ground balancing is a crucial function that adjusts the detector to the mineral content of the soil, ensuring accurate readings. EMI can interfere with this process, making it challenging to achieve a proper balance. As I noted in my ground mineralization article, when a detector isn’t correctly balanced to the ground, it can produce erratic signals, further complicating the detecting process.

Unreliable Target Identification

Most modern metal detectors come equipped with target identification features, categorizing detected objects based on their conductivity. EMI can skew these readings, causing the detector to misidentify targets. A piece of aluminum might be mistakenly identified as a gold ring, leading to misplaced excitement and potentially unnecessary digging.

Inconsistent Depth Reading

Depth indicators on metal detectors provide an estimate of how deep a target lies. EMI can disrupt this feature, leading to inconsistent or inaccurate depth readings. As a result, detectorists might dig too shallow or too deep, missing the target or expending more effort than necessary.

Combatting the Effects of EMI

While EMI sounds daunting, with the right strategies, you can minimize its impact:

Adjusting Frequency

Some advanced metal detectors allow users to switch frequencies. If you’re experiencing interference, changing to a different frequency can help.

Maintaining Distance from Developed Areas

If possible, try to keep a safe distance from known sources of EMI, such as power lines or radio towers. If you’re metal detecting near new developments or inside city limits you’re more likely to encounter this issue.

Dig Every Target

Sometimes the best solution is often the simplest. If the area you’re hunting on has EMI issues, it might be best to adopt the tried and true “Dig Everything” mantra many detectorists always adhere to anyway. Since the EMI might have caused previous detectorists to miss targets or avoid the area entirely, you might end up finding some hidden gems with accidental assistance from our typical noisy nemesis.

Other Factors Impacting Metal Detection

While ground mineralization, target size, depth, and electromagnetic interference are common metal detecting challenges, there are other factors that can influence your detecting experience. In this section, we’ll briefly shine a light on these additional elements.

Environmental Conditions

Mother Nature can play a significant role in your detecting sessions:

Rain and Wet Ground

Wet ground can enhance conductivity, making some targets more detectable. However, it can also amplify ground mineralization. This is a common issue for detectorists that frequent saltwater beaches.

Swing Technique

An inconsistent or improper swing technique can result in missed targets or false readings. If you’re not maintaining a consistent height and swing speed you could be missing targets that might have been detectable.

Magnetic Anomalies

Natural magnetic anomalies, often caused by variations in the Earth’s crust or specific mineral deposits, are rare but can create unique challenges for metal detecting. These anomalies can amplify the effects of ground mineralization, increasing the electromagnetic interference (EMI) experienced by the detector. The result is a heightened sensitivity to false signals and a potential reduction in detection depth. Furthermore, magnetic anomalies can interfere with a detector’s internal components, skewing readings and making target identification unreliable.


Regions with a history of heavy industrial activity often bear the scars of pollution, even long after the industries have ceased operations. Over time, metallic residues from factories, mines, and other industrial sites can leach into the soil. These residues, whether from discarded waste or atmospheric deposition, can introduce a myriad of metallic particles into the ground. For metal detectorists, this means an increased likelihood of false signals and difficulty in distinguishing valuable targets from industrial remnants. The legacy of industrial activity can thus pose a significant challenge, requiring more discerning techniques and equipment to navigate effectively.

Recommendations to Improve Your Metal Detecting Experience

Metal detecting is a blend of persistence and patience, and while we’ve delved deep into the factors that influence it, there are always ways to refine and improve your detecting sessions. Based on our comprehensive exploration, here are some expert recommendations to elevate your next metal detecting expedition.

Research Location History for Past Human Activity and Weather Events

The more your research, the more likely you will be to find something. The hunt doesn’t begin when you’re out in the field, it begins when you chose a location and dig into its history.

The history of a location can provide invaluable insights for metal detecting. Areas that have witnessed historical events, such as battles, trade routes, or old settlements, provide a higher likelihood of possible pocket change escaping an old merchant’s coin purse. 

However, they might also have been subjected to disturbances like trench digging, building constructions, natural resource extraction, or floods. 

Researching a location’s past can give detectorists an idea of where to search and what to expect. For instance, a site of a former trade route might yield coins, while a battlefield might offer relics like bullets or military badges. A flooded area or an area that has suffered a landslide might produce more trash debris, but it could also turn up deeper buried items too. Being informed about a location’s history can guide the search, making it more targeted and potentially rewarding.

Invest in Quality Equipment

Upgrade to a Modern Metal Detector

While starting with a basic single-frequency model is fine for beginners, as you gain experience, consider investing in a more advanced detector with features like ground balancing, frequency adjustments, and discrimination settings

In my opinion, you should at least start out with a simultaneous multifrequency device like the Minelab Vanquish series which will help reduce potential sources of user error while you gain experience and a better understanding of the device,

Try Multiple Coils

Having a variety of coil sizes and shapes can help you better adapt to terrain and ground conditions. Larger coils can help in covering vast areas and detecting deeper targets, while smaller coils are easier to use in rocky terrain, are excellent for pinpointing, and excel when working trash-heavy sites.

Respect the Environment

Practice ‘Leave No Trace

Always fill in your holes and ensure that the area looks as it did before you started detecting. If you’re digging in public parks this should be your highest priority. Cities and counties are quick to ban metal detecting when issues with poor digging techniques become persistent.

Dispose of Trash Properly

Even if it’s not a valuable find, always take trash with you. This not only cleans the environment but also makes it easier for your next detecting session in the same area. I can’t count how many times I’ve found a relic or coin on my third or fourth trip to the same location. If you find a reliable spot you can consistently access, treat it like a long-term project. The more trash you take out, the less interference you will have as other targets shift around and make their way back to a detectable depth.

Document Your Finds With Basic Details

Maintain a Journal

Documenting the details of your finds, including location, depth, and item description, can help you identify patterns and improve future hunts. This information can help you track high-density areas for future visits, lead you to new areas that might have been a previous settlement or camp, and even provide historical provenance making your finds and the property more valuable.

Photograph Your Treasures

A visual record can be invaluable, especially if you’re considering showcasing or selling your finds. I personally have both my journal and photos on my phone. When I record the items I always snap a photo and save it directly in the note for clear context and easier recording when I get back home.

Understanding Common Issues Goes a Long Way

From the intricacies of ground mineralization to the nuances of target size and depth, from the invisible hurdles of electromagnetic interference to the subtle influences of environmental conditions and operator skill, every aspect plays a role in shaping our detecting adventures.

But with challenges come solutions. By understanding these factors, equipping ourselves with the right knowledge, tools, and techniques, and approaching each hunt with patience and persistence, we can navigate our unique challenges and uncover the stories that lie beneath our feet.