Metal Detector Frequencies: A Beginner’s Guide from a Technical Perspective

by Chad Eicher

METAL DETECTING FREQUENCIES GUIDE

Welcome to the ultimate. detector frequency guide, a must-read for beginners.

The metal detecting hobby, is an enthralling blend of scientific understanding and the excitement of uncovering hidden treasures. At the heart of this intriguing activity lies the mastery of metal detector frequencies, which determines the success of every treasure hunt. 

As an experienced detectorist, I’ve witnessed firsthand how a deep understanding of these frequencies can turn a leisurely pastime into a fruitful endeavor.

This guide is crafted to demystify the technical aspects of metal detector frequencies, making them accessible to enthusiasts embarking on their metal detecting journey. 

Understanding the frequency it produces is key to successful detecting. Whether it’s unearthing historical relics or finding lost jewelry, the right frequency can make all the difference.

Understanding Frequencies

First of all, what is a metal detector frequency? The frequency of a metal detector refers to the rate at which its search coil emits electromagnetic waves into the ground.

Measured in kilohertz (kHz), these waves interact with metallic objects, causing the detector to signal their presence. This interaction is crucial in determining what the detector finds and how deep it can search.

frequencies wave

Frequency and Target Detection

The choice of metal detecting frequencies is pivotal, as different targets respond better to different frequencies. For instance:

Low Frequencies (Below 10 kHz): Ideal for detecting large objects and achieving greater depth, making them suitable for items like coins and large relics.

High Frequencies (Above 15 kHz): These frequencies are sensitive to smaller, low conductivity targets such as gold nuggets or fine jewelry. Pulse induction technology, often operating in the kHz range, excels in detecting these types of targets.

Balanced Frequencies: A mid-range frequency can provide a versatile detecting experience, suitable for a variety of targets.

Understanding these fundamentals is the first step towards harnessing the full potential of your metal detector, and equipping you to make informed choices on your detecting adventures.

Low vs High Frequencies: A Practical Guide

Low Frequencies Explained

  • Depth Penetration: Low-frequency waves, typically below 10 kHz, have the ability to penetrate deeper into the ground. This makes them ideal for detecting large objects like old coins and relics.
  • Target Types: They are particularly effective in finding high conductivity metals such as copper and silver.

I recall a time when I was using my old Ace 250 in a park, where its low frequency unearthed an old, deeply buried coin that was missed by higher frequencies.

Recent developments in metal detector technology, such as very low frequency (VLF) metal detectors, enable discrimination between different metal types (copper, iron, aluminum) and improve detection depth and accuracy (Sharawi & Sharawi, 2007)

High Frequencies and Their Advantages

  • Sensitivity to Small Targets: Frequencies above 15 kHz are more sensitive to small, low conductivity metals, perfect for hunting gold nuggets or delicate jewelry.The Fisher Gold Bug Pro is a notable detector in this range, favored by gold prospectors for its extraordinary sensitivity.
  • Ground Mineralization Handling: They perform better in highly mineralized soils, where lower frequencies might struggle.
Metal detector frequencies comparison

A few years ago, while searching on a  beach in Florida, switching to a higher frequency revealed a small gold ring, invisible to lower frequencies.

Embracing Advanced Metal Detecting

Multi-Frequency Systems

These detectors use multiple concurrent frequencies, offering the best of both worlds.  The depth capability of low frequencies and the sensitivity of high frequencies. The Minelab Equinox series, for example, uses multiple concurrent frequencies, allowing it to perform well in different soils and for various target types, from coins to relics.

Versatility in Detection

They are adaptable to various ground conditions and target types, making them suitable for diverse environments.

Pulse Induction Technology

Powerful and Deep Seeking: Pulse induction (PI) detectors, like the Minelab GPX 7000, send powerful, short bursts (kHz pulse induction) into the ground, utilizing a full band spectrum for comprehensive metal detection.

This type of technology is particularly effective for hobby metal detector enthusiasts seeking to locate deep treasures. They are less affected by ground mineralization, making them ideal for challenging terrains like saltwater beaches.

Different Coil Pulse Induction

PI systems can use various coil designs, each offering unique detecting benefits, from broad coverage to focused detection.

Full Band Spectrum Utilization

By covering a wide range of metal detecting frequencies, PI detectors offer comprehensive detection capabilities, especially useful for deeply buried or highly conductive targets.

The evolution of metal detecting technology, from single-frequency to sophisticated multi-frequency and PI systems, has revolutionized our ability to uncover hidden treasures in the most challenging conditions. This technological leap has opened new possibilities, making metal detecting an even more exciting and rewarding hobby.

Metal Detector Frequencies for Different Environments

Influence of Soil Composition

The performance of your detector is heavily influenced by the ground you’re searching in. For instance, wet beach sand with high salt content can cause false signals in standard detectors. However, models like the Minelab CTX 3030 (read review), with their ground balancing features, can adapt to such conditions, for more accurate detection.

Mineralization Challenges

Highly mineralized soils, like in a beach, can hinder detector performance. Detectors like the Garrett AT Pro, with adjustable frequency settings, can counteract this by reducing interference from mineralization.

Adapting to Your Environment

As a beginner, start by understanding the type of ground you’ll be searching. If you’re near beaches, consider a detector with ground balancing and waterproof features. For inland, less mineralized areas, a general-purpose detector could be your go-to choice.

Practical Tips for Beginners: Choosing the Right Frequency Settings

So, ‘which metal detecting frequency should I use?’ you may ask.

For starters, begin with a mid-range frequency setting to get a feel for your detector’s response in your local area. Use your detector in various environments and note how different settings affect your findings.

Best Metal Detecting Frequencies for Different Types of Metals

For gold, high frequencies, typically in the range of 18-71 kHz, are ideal. Specifically for small gold nuggets, frequencies around 45-71 kHz are highly sensitive.

For silver, lower frequencies, usually between 6-15 kHz, are effective. Around 10 kHz is a sweet spot for silver as it offers a good balance between sensitivity and depth. Garrett AT Pro, with a frequency of 15 kHz, is excellent for silver items.

For coins and coin shooting, mid-range frequencies, about 8-12 kHz, work well for most coins. Garrett Ace 250, operating at 6.5 kHz, is a popular choice for general coin shooting.

If you’re into finding relics, which are usually deeper, lower frequencies, typically between 5-10 kHz, are recommended. Minelab CTX 3030, with its multi-frequency technology including lower ranges, is great for relic hunting.

On the other hand if you like hunting for jewelry on beaches, mid to high frequencies, around 10-20 kHz, are effective. The Fisher F75, with its adjustable frequency up to 81 kHz, can be tuned for different types of jewelry.

Experimentation is Key

Don’t hesitate to experiment with different settings. For instance, try low frequencies in areas with deep coins or relics and switch to higher frequencies in gold-rich regions.

Learn from Experience

Over time, you’ll develop a sense for which frequency settings work best for specific targets and conditions. Remember, each outing is a learning opportunity, and your skills will improve with practice.

With practice and experimentation, you’ll learn to optimize your detector’s settings for any situation, enhancing your chances of making exciting discoveries.

Conclusion

To get a thorough understanding of frequencies is like unlocking a treasure chest of possibilities. Each frequency you choose is a key, opening doors to different types of finds, from ancient relics to modern lost items. 

As you grow in this hobby, you’ll discover that the right frequency not only enhances your detecting efficiency but also deepens your appreciation for the science behind this fascinating pursuit.

And don’t forget: education is key. If you are keen to delve deeper into the technical aspects of metal detecting, a wealth of resources is available. Books, online forums, and metal detecting clubs offer invaluable insights.

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Article by

Chad Eicher

Detectorist Chad is passionate about metal detecting since he got his first metal detector as a gift when he was 12 years old. He created Metal Pursuits to share his knowledge and create the ultimate metal detecting resource on the web.

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