How Do Metal Detectors Work?

how do metal detectors work

Are you wondering how do metal detectors work? This question is one that many people are asking. Indeed, even we can’t help but wonder how a device can locate metals and other valuables like gold and silver.

Metal detectors may look simple devices at first glance, but the inside mechanism is extremely complicated. Today, we’ll talk about this awesome innovation and its main purpose in the industry.

What Is a Metal Detector?

When you hear “metal detector,” what is the first thing that comes to your mind? Most people would say that they think of it as a device used to look for buried coins, jewelry, or treasures. Others would think of the device used by security personnel to check our bodies and our belongings when entering malls or airports.

Basically, both are true; the devices described above are both metal detectors. You may use a metal detector to look for lost jewelry or coins around the house, or you can use it to locate metals buried underground. And, yes; those things used by security guards to scan our body are also considered metal detectors.

Parts of a Metal Detector

In order to understand how a metal detector works, we first need to get to know the basic parts that make up one. Below, we would be focusing on regular metal detectors used for treasure hunting.


Some metal detectors have stabilizers; others don’t. The main function of this part is to keep the unit steady while you are sweeping it back and forth, trying to look for coins and other metals.

Control Box

The control box is the part of a metal detector that holds the controls, circuitry, batteries, speakers, and, of course, the microprocessor.


The shaft is the part that would connect the control box and the coil. This can be adjusted to the height that you want; you can lengthen or shorten the shaft depending on your preference.

Search Coil

This is more like the antenna of the metal detector, and it is responsible for detecting the metal on the ground.

How Do Metal Detectors Work?

Metal detectors are very complicated. Although they are very easy to use, the processes that are happening inside that small device are actually very intricate. Before we find how it works, how do you use a metal detector, anyway?

Of course, the first thing you need to do is to turn the unit on. Then, move the detector slowly while walking. You can slowly bring it to a certain location, and you can sweep the coil back and forth on the ground.

An audible signal will happen if you pass it over a target object. Advanced metal detectors can actually pinpoint the metal that it has detected, and it would indicate the depth of the targeted object as well.

Pretty simple, right? This is just the basic method of using a metal detector, and it contains so many features that you would need to spend a lot of time learning about. Now, let’s proceed with the process of how these metal detectors work.

  • After turning the metal detector on, the battery would activate the transmitter circuit inside. It will then pass down the electricity through the cable from the handle towards the transmitter coil at the bottom.
  • Once the transmitter coil receives the electricity, it will then create a magnetic field around the coil. The magnetic field will serve as the antenna; it would search for metals on the ground.
  • If you try to sweep the metal detector to a certain metal, the magnetic field from the coil will seep through it. It will then create an electric flow current in the metal object that you targeted.
  • The flowing current will then create another magnetic field around the object. The signal will then be sent through the receiver coil, and it will move it up to the receiver circuit.
  • When this happens, a buzzing sound will be released by the metal detector, indicating that you found a certain metal.
how do metal detectors work

Important Features of Metal Detectors

Metal detectors have certain features that you would need when you are hunting for treasure. Your metal detector should have all these features to make sure that you won’t have a hard time searching for specific metals on the ground.

Here are some of the features that your metal detector should have:

1. Discrimination

This is one of the most important features that you want in your metal detector. The main function of this feature is to help your device to distinguish if a target is a piece of trash or a valuable metal.

You have to remember that there are so many metals that you can find buried in the ground, like bottle caps, screws, and more. You cannot simply dig continuously just because your metal detector managed to find a metal on the ground.

There are metal detectors that would auto-adjust, or you can just do this manually. The thing is that you should always check this feature on a metal detector. Although most models have this, it is better to be sure.

2. Ground Balancing

The level of mineralization in the soil can mask valuable items. This is a very important thing to know because your metal detector won’t be able to detect any valuable items if the level of mineralization in the soil is very high.

The soil contains a minute level of metal, and this will interfere with the ability of your detector to find jewelry, coins, and more. By having a ground balance feature, the detector will be able to bypass all these unnecessary items.

There are also different variations of this feature for metal detectors, such as:

  • Automatic: This type of ground balancing will automatically detect and adjust depending on the soil.
  • Preset: The manufacturer will set the ground balance on a level that would work on different types of environments.
  • Manual: This will require you to make the adjustment yourself. This is the best choice if you are looking for gold because of the changes in ground conditions.
  • Multiple: This type of ground balancing feature allows you to choose automatic or manual balancing. It means that you can balance the ground manually, or you can choose to let the metal detector do it automatically.

3. Target Identification Feature

This is the feature that you need to determine if the metal detector is detecting a valuable or trash item. Basically, this feature will produce an audible tone that would indicate if the targeted metal is valuable or not. This may differ depending on the metal detector, but usually, high-pitched tones indicate valuable items while low grunts are trash items.

There is also a certain feature that would indicate the type of metal directly on the LCD screen. An arrow will appear on the screen, indicating the type of metal that you are presently targeting.

4. Operating Frequency

Metal detectors differ depending on their operating frequency. Most of the regular metal detectors, including the ones that are made for kids, are usually operating at a lower frequency. It can scan deeper into the ground, so they provide a much better detection depth.

Higher-frequency detectors are sensitive to smaller objects and gold. This means that if you are serious with gold hunting and looking for other valuable minerals, using a higher-frequency model will help you greatly. The only problem is that they won’t be able to penetrate deep into the ground compared to lower-frequency detectors.

5. Sensitivity

Another important feature of a metal detector is sensitivity. This will determine the ability of the detector to locate metal objects from far away. If you put the sensitivity too low, you won’t be able to detect any metal at all, and if you put it too high, what you’ll find are trash metals.

Therefore, you need to have the right value for the sensitivity level. Most manufacturers will suggest a good level for certain situations. If you want to know how do metal detectors work, you will have to understand their features.

Technologies Used in Metal Detectors

To further understand how metal detectors work, you should also know the different technologies that are being used in these devices. In this way, you’d have a better understanding of how it functions the way it does.

1. Very Low Frequency (VLF)

It is commonly known as induction balance, and it is the most popular technology used on most metal detectors right now. There are two types of coils in a VLF metal detector:

  • Receiver Coil: This is the inner coil loop that has another coil of wire. It will serve as the antenna, and it will receive and amplify the frequencies coming from the target in the ground.
  • Transmitter Coil: This is the coil loop on the outside. Inside is another coil of wire, and electricity will be sent to this wire.

The transmitter coil will create an electromagnetic field. Every time the current changes its direction, the polarity will change as well. If the coil of wire is parallel in the ground, the magnetic field will push down and pull it back up to send the pulses to the receiver coil.

2. Pulse Induction (PI) Technology

This is not a common form of metal detector. PI systems use a single coil as the transmitter and the receiver, or they may also have two or three coils that work together.

If you put the metal detector over a metal target, the pulse will start creating an opposite magnetic field on the targeted object. Once the magnetic field collapses, the magnetic field from the object will make sure that the reflected pulse will take longer to disappear.

3. Beat-Frequency Oscillator (BFO) Technology

This is the most basic method of detecting metal. In this kind of system, there are also two coils of wire used. There is a large coil located in the search head, while the smaller coil is in the control box. The coils are connected to an oscillator, which would generate thousands of pulses every second.

The coil will create radio waves as the pulses actually travel through each coil. The receiver will pick up these radio waves, and it will create a series of tones. If you hear a series of tones, that just means that the metal detector found metal in the ground.

Finding Metals on the Ground

Finding metals on the ground is not as simple as you think because these metal detectors are not capable of detecting metals on the deepest parts of the ground. Most models can only detect materials eight to 12 inches below the ground, but it is affected by different factors, such as:

1. The Type of Metal Detector

The depth of the metal detector will depend on the type of technology being used. VLF detectors use higher frequencies than the others, and there are other technologies that use small and large coils.

2. Type of Metal in the Object

You should know that some metals, like iron, can create a stronger magnetic field compared to others, and it can affect the depth of your metal detector.

3. Soil

There are minerals in the soil that can actually interfere with your metal detector in that it can affect the depth that your metal detector can reach.

All these factors will affect the depth of your metal detector, so if you are disappointed with the model that you bought, you should check the area where you are trying to look for valuable metals.


Knowing how a metal detector works can help you analyze the device if it is not doing its job properly. Alternatively, how it works will also depend on what type of metal detector it is and the features that it has.

If you’re planning to buy a metal detector for yourself, make sure that you know what features you prefer and the type of technology that you need. There are some metal detectors made for leisure activities, and there are others that were created for the purpose of finding gold and other valuable minerals. You need to determine your goal and choose a metal detector based on that.

Metal Detecting Accessories

metal detecting accessories

With more and more people finding the hobby of metal detecting fascinating and fun, they need to know what would make their hobby the most fruitful and fun. For anyone who is metal detecting for a hobby, there are some must haves to make their hobby successful and fun.

A person who goes out metal detecting without all the proper tools and accessories can find their time hard and not very fun experience. If they are prepared with the proper tools, they will have a better time with being able to carry their finds as well as dig up anything that they find with their metal detector.

Some of these accessories for metal detecting include pinpointers, headphones, digging tools, sand-scoop, pouches, and an excellent backpack. While this is a list of the most important items that a person should have with them, it is not all that they can have with them.

Metal Detecting Pinpointers

A pinpointer is a very handy tool for a hobbyist because it is a smaller version of a metal detector.

Once the person has found their item with their normal metal detector, they can then use the pinpointer in order to narrow down where the item is while they are digging it out of the ground by pointing a laser light at the location of the object, which shows them right where to dig.

There are pinpointers that can be attached to the person's finger or wrist, but there are also larger scale ones that have to be carried around like a flashlight. Now, a person does not have to have a pinpointer with them when they are metal detecting, but having one with them will help them find their objects much faster because a large scale metal detector can only show the general area.

A pinpointer can narrow down the area into a fine and precise location so that the hole that has to be dug is much smaller, which means that the item found can be dug out much quicker and more efficient. There are also special types of pinpointers that can be used when metal detecting under water.

Metal Detecting Headphones

While there are a lot of hobbyist that do not believe they need to use headphones while they are metal detecting, there are a large number of them that would also highly recommend using them.

Not only do headphones help a person to better hear their metal detecting machine when it finds something, but they also help block out any sound that there might be around them.

If someone were to metal detect at a beach or park, there would be a lot of sounds of the other people that would also be at that location, such as screaming kids. An excellent pair of noise canceling headphones would help them to block out all other sounds in order to better focus on their task, which means they would have a more productive and fun time.

While there are simple headphones that can be used just to make it easier to hear their metal detector, which would mean they would still be able to hear the sounds around them, there are also much nicer pairs that would block out everything but the machine. The headphones that block out more sounds are larger, so the type of headphone would depend on the size the hobbyist is willing to carry.

Metal Detecting Gloves

Gloves are one of the those things that a metal detecting hobbyist must have with them in order to make their time fruitful and fun.

Without a pair of gloves, they would get hurt when they are trying to dig out what ever they may find, plus it would help to keep their hands clean. A person who tries to clear away dirt or rocks without a pair of gloves can cut their hands or hurt their nails.

While a thin pair of gloves would be easier to carry and would work fine to shift through a little bit of dirt, a thicker pair of gloves would be better at protecting the persons' hands. The main things that would play into what pair of gloves would be perfect for the hobbyist is if they want something thinner and easier to carrier or something thicker and more protective.

Thicker gloves would also retain heat, so the hobbyist would have to be ok with their hands being warm as they do what they need to until they can take them off again. There are some gloves that can be made out of material such as leather they protect well but also allow air flow.

Metal Detecting Digging Tools

metal detecting accessories

While there are many different types of digging tools that someone can use when they are metal detecting for a hobby, it is important to keep in mind that some kind of digging tool will be needed in order to retrieve what ever was found with the detector.

While things that are found close to the surface can be dug out using your fingers, many things are actually some distance under the ground, which means they are harder to reach. The location in which the hobbyist is metal detecting will play key into what type of digging tool will be needed and needs to be kept in mind.

Metal Detecting Trowel

As stated, the location of the metal detecting places a large roll into what type of digging tool is needed, but a trowel is a handing digging tool that would be handy in just about every location.

While a trowel is just a small, handheld shoveling tool, which means it is not good for digging large holes, it is perfect for something that is not very far under the ground.

The small size makes it much easier to carry then many other digging tools, and it makes it easier to move in order to shift through a pile of dirt that has already been dug out to find the item that they person has found.

If the trowel is made of hard metal as many of them are, they would be good for digging through many different types of material, such as dirt, clay, and sand. While most trowels are made of metal, there are some that can be bought that are made of hard plastic, which means they would be more limited in what they would dig through.

Now, while trowels are very easy to carry and use, they by no means will get the whole job, which needs to be kept in mind.

Metal Detecting Shovel

Shovels are the number one digging tool that most hobbyist need with them no matter where they are metal detecting.

While most people do not like to carry a shovel with them when they are metal detecting because of their size, they are very key to any outing be fruitful and fun. A person does not want to spend a long amount of time digging in one spot, and a shovel would help them to dig that area at a much quicker pace.

For the hobbyist that does not want to carry around a large shovel, there is the option of a small handheld shovel, but they are small and about the size of a trowel. The small size would mean the digging would take a longer time, which can take the fun out of finding the item.

Plus, the longer it takes to dig the item, the more time is taken from finding other items. If a person plans to metal detecting close to their vehicle, they can always leave their shovel in their car and just mark where they find the items that take a little more digging then other items would take.

Metal Detecting Sandscoop

A sandscoop is one of those tools that can make a metal detecting hobbyists time very easy and fruitful.

It is often a tool that is overlooked by many people because the task that this tool accomplishes can be done with a persons hand. A sandscoop takes a load of dirt, sand, or other ground material and shifts out larger pieces from the smaller, finer material.

While this tool is often called a digging tool, it is actually not wise to use this tool for digging because a majority of the minerals will fall through the holes and back down into the hole that is being dug. This tool can be bought as a small handheld tool or a much large tool.

The smaller tool would be easier to carry around, but the larger tool can shift through the minerals much faster and more at one time. While this tool does help shift through the material being dug through, it does not shift everything.

If there are rocks or larger clumps of dirt, the scoop will not shift through them, so the hobbyist will still have a little shifting that needs to be done in order to find the item.

Metal Detecting Pouch

Some perfect metal detecting accessories are pouches. Pouches make it easy for a metal detecting hobbyist to carry anything and everything that they might find while they are walking around and trying to find things.

Pouches can also be helpful for carrying anything that they may want or need to carry with them, such as medical supplies or personal items. Pouches can be handy to keep personal items separate from items that are being found and dug by the hobbyist.

While a hobbyist can find many different items, some of the items may be the same type, such as money or clothing items, so pouches can be used to keep these items sorted out to make looking at them further later on easier.

Pouches can be bought in many different sizes, colors, and materials. The size and material of the pouch would all depend on what might be going into them.

Personal items can be kept in pouches that are thin, but things that are dug up might be sharp and would need a thicker pouch to carry them in. The color on the other hand would not be as important unless the person likes to color code the items that they are carrying and find.

Metal Detecting Backpacks

Backpacks are another one of metal detecting accessories that are very important in order to make the metal detecting hobby fruitful and fun.

A person does not want to have to carry everything that they need and find while they are metal detecting, so a backpack is essential to them having a good time.

There are many different types of backpacks that can be bought and used for metal detecting, and it would just depend on what level of metal detecting they are planning on doing.

Someone who is just doing a quick search would not need anything that is too large or has a large amount of pockets, but someone who does a lot of metal detecting, has a lot of tools, and plans to be out for a while would need something larger in order to carry everything that they might need, such as their tools, water, food, and medical supplies.

For people who plan to do a lot of hiking while the are metal detecting, they would need to be able to carry a lot more things, such as extra clothing and possibly a sleeping bag.

Final Thoughts

In conclusion, while someone is metal detecting, there are many things that they should know.

Something that is extremely important that a hobby metal detector needs to keep in mind is having all the proper equipment with them in order for their experience to be successful and fun.

Some of these accessories for metal detecting include pinpointers, headphones, digging tools, sand-scoop, pouches, and a backpack.

While these are a few of the most essential and important tools that a hobby metal detector needs in order to have a fun and fruitful time, it is not everything that they could find handy the them during their hobby practice.

What Do Metal Detectors Detect?

what do metal detectors detect

If you've been wondering what do metal detectors detect, we've got all the answers for you below!

When the topic of metal detecting as a hobby comes up, many often picture a strange old man finding bottle caps on a local beach side. However, in reality, metal detecting can bring lots of joy, possible treasure and even a great form of exercise for us! The thrill of metal detecting is similar to that we get when hunting for Pokémon on Pokémon Go. But instead of virtual creatures, we can hunt for real tangible items!

The more our community begins to spark interest in metal detecting as a hobby, the more we are able to learn about differing kinds of metals and objects, Additionally, we gain a general interest in local history as ancient treasure is discovered.

How Metal Detectors Work

You might be wondering just how metal detectors are able to find and uncover buried goods that might have been in a specific location for so long. The science of it all is actually a lot simpler than you might think!

A metal detector is essentially composed of a battery, a control box, and a search coil. It works by transmitting an electromagnetic field from the coil in the detector to the ground. All metal objects in this field become energized and resend or retransmit an electromagnetic field back to the coil. Once the search coil on the detector receives the transmitted field, it alerts us by producing a specific response signal or sound.

When asking, what do metal detectors detect? Rather obviously, the answer is in the name, metal!

Interestingly though, different kinds of metals transmit distinct electromagnetic fields. Depending on the type of metal detector you have or select, settings can be set to only scan for targeted or desired metals.

This allows users to easily ignore unwanted products, such as bottle caps (depending on our interests, some of us seek these for unique and really vast collections!). We do this by adjusting the setting on the metal detector to not transmit a field that would detect aluminum, a common element in bottle caps.

How Deep Can Metal Detectors Detect

The quick answer, anywhere from 7 inches to 20 feet! There are many factors that effect how deep metal detectors are able to detect. Some of those factors include the soil type, the size of the object, the wetness of the ground, and the type of metal detector purchased.

Mineralized soil tends to give us fake or mixed signals. The size of the object matters as larger metal objects are more easily detected, even though the object may be deeper into the ground. Wet ground tends to uncover newly buried coins especially after a rainstorm.

There are many brands of metal detectors at different price points and different weights. Because of this, the depth of the detecting field is varied.

Kinds of Metals

More commonly, metal detectors are able to and do detect iron, copper, aluminum, tin, nickel, brass, and lead. However, excitingly, these detectors are also able to locate bronze, silver, and especially gold!

We can set our devices to only emit a specific electromagnetic field to find target metals. However, many metals often have similar identifiable features and transmissions. With this in mind, we cannot set the detector to only search for gold, although larger pieces maybe slightly more readable.

Kinds of Objects

General objects that can be found using metal detectors include jewelry and coins. Some have found unique items including a bronze axe head dating back to 1800 BC. Others have found a gigantic chalice made of gold and studded with amber. These kinds of finds are not commonly found and take patience and huge amount of luck. However, such potential treasures make the hunt an ever more enticing encouragement to continue metal detecting!

Enthusiasts have found coins that date back to 155 BC and meteors that have been buried for more than 10,000 years. You can see that the kind of objects that can be found using metal detectors can offer a unique insight into our world’s and people’s history.

what do metal detectors detect

Can Metal Detectors Find Gold

The short answer to this question is…yes. Metal detectors can find gold, but with large variance.

While all metal detectors can detect gold, not all are created equally. Several kinds of detectors are made that are more specific and sensitive to gold and are therefore made for those of us solely interested in finding gold jewelry.

Metal detectors designed specifically for gold hunting are made to cancel out mineralization. It is therefore important to understand the geography of the targeted region first.

There are typically two kinds of detectors for gold-hunting. A very low frequency (VLF) detector and a pulse induction (PI). VLF detectors offer a higher sensitivity to small gold nuggets, while PI detectors are able to detect larger nuggets found deeper in the soil.

Pulse Impulse detectors can even function in mineralized soil. They are, of course, pricier as a result and are the newer current technology.

Can Metal Detectors Find Aluminum

Did you know that there have been instances in which the aluminum foil wrapper found commonly in chewing gum set off alert signals at airport security? Strange to think about but this has actually happened before.

Metal detectors are able to find aluminum because as a non-ferrous metal it is naturally non-magnetic. But it is a pretty good conductor of electricity. When it comes to metal detectors, objects made of/or containing aluminum are easily and very commonly detected.

Unfortunately, many aluminum finds are pretty useless. Who wants to find a ring-pull anyway? 🙂

Can Metal Detectors Find Titanium

Titanium is a type of metal that is difficult for us to find as it is not easily detectable by a metal detector. A newer metal detector can be used to find titanium. But Titanium is neither a good conductor of electricity nor magnetic. This means it is super hard to find and requires lots of patience!

First, we have to set our metal detectors to a lower frequency. We also have to be conscious of the type of soil we are searching in. Highly mineralized soil is more difficult to work with unless you have great experience in it.

What is Discrimination in Metal Detecting

After turning on your metal detector and beginning to hunt, you will notice that everything that is detectable will be detected. This includes metallic pieces of trash and mineralized ground too. Discrimination in metal detecting is when we slowly begin to add a differentiator so that only a specific range is detectable.

To learn how to discriminate, you slowly begin by trying to search for coins or foil on the ground and then gradually increase the differentiation. With regular practice, you can begin to determine what type of signals you are picking up and whether you feel its worth the hunt!

Bottom Line

So, what can you find with a metal detector? Lots of things!

From non-valuable mineralized soil, pieces of trash to large gold nuggets. Metal detectors are for those of us who are patient but eager to go on a hunt for treasure!

With time and practice, we can all learn how to search for objects that spark our interests. We also learn about our historical surroundings and often can cash in some of our enticing finds!

Finding Coins With a Metal Detector

finding coins with a metal detector

Below we have some great tips for finding coins with a metal detector. Coins are by far the most common items of value that most people find when out treasure hunting. It is a little known fact that there are more coins that have been lost than there actually are in circulation!

Coins can and do turn up just about anywhere. If you have the time to detect and a place to go, then go ahead and give it a try. Though the location may not be the best, you are still more likely to find coins while metal detecting in a poor area than just sitting at home doing nothing. In addition, anytime that you spend metal detecting will help you to build skill and become better with the detector.

While it is not often that a person finds gold coins, silver coins are found somewhat regularly. However, even finding a dime or even a penny is better than a day detecting and finding nothing.


In many areas of the country, fairgrounds have been used for decades. Over the years, many coins have been dropped and are just waiting to be found. Though getting permission can be difficult, these areas are great producers and are generally peaceful places to detect. Racetracks and athletic fields provide similarly productive places to detect for coins, especially in the off-season when no one else is around.


Beaches are one of the most productive areas to metal detect for the simple reason that it is easy to dig in sand. From the ocean to the local river's swimming hole, any area where people sunbathe, swim or relax by the water can produce coins. By going in the off-season these areas will likely be abandoned and you can detect without working around or bothering other people. Metal detecting on beaches can be especially productive in periods of low water when fresh ground is exposed.

Old Home Sites

Places where homes once stood can be a productive place to find coins with a metal detector. This is especially true on private property where few people have ever metal detected. Coins can often be found near the edges of old homes, presumably near porches or steps where pocket change was dropped. Always watch for cornerstones or other indicators of where a home or other building once stood when detecting in a new area. Though these old home and buildings may be gone and forgotten, there are likely to be some coins waiting to be found. Even modern homes can be a great source for coins, both new and old.

Underwater Metal Detectors

underwater metal detectors

There are a variety of underwater metal detectors available on the market today.

When choosing a model you'll need to decide whether you will be underwater metal detecting fully submerged while scuba diving, or whether you will use the detector at the waters edge.

Obviously, if you intend to fully submerge the metal detector you'll need to ensure that all of its components are fully waterproof. Remember also to check the depth to which they are rated. Most fully underwater metal detectors are rated to 100 or 200 ft. These will suit all but the most experienced of scuba divers and professional treasure hunters.

If you are intending to use the machine at the waters edge where only the coil will be underwater, detectors classed as 'waterproof' will be sufficient.

Once you've decided upon the use of the detector you'll then to need to decide on the type.

Types of Underwater Metal Detectors

In general, these are the four main types of underwater metal detectors are currently sold online and in stores.

1. Pulse Induction (PI)

Pulse induction metal detectors function by emitting a series of electronic pulses into the ground beneath them. The pulse circuit goes deeply into the ground through the water.

The pulses, which are short and quick, are quite sensitive to precious metals. However, they are not affected by ground minerals or wet sand. This makes them ideal for saltwater environments such as beaches.

The drawback is that this type of detector does not discriminate well between trash and treasure. This may lead to just as many poor finds as valuable discoveries. Pulse induction metal detectors perform well no matter what type of ground condition exists.

PI metal detectors do tend to be more expensive than their VLF brothers. However, heir increased effectiveness in marine environments is often regarded as outweighing their extra cost.

2. Very Low Frequency (VLF)

Very low frequency metal detectors function using a low frequency range of 3 to 30 kHz. This style of detector has good discriminating capability and can determine coins relics and jewelry from trash. Unfortunately, this style of detector can be affected by minerals contained in the ground or sand.

To overcome this, many of these models offer a sensitivity adjustment as well as a ground-balance adjustment. This provides an opportunity to tweak your settings based on your findings. If you do decide on a VLF style detector, be sure that it offers a salt water mode.

3. Beat Frequency Oscillation (BFO)

This is a very basic system and are generally used for very cheap or budget metal detectors. Essentially they are two rings of copper around iron or steel with a current passing between the two. The current is sent into the ground and if the signal is broken an audible beep is sent to the user.

The main thing to remember is that they have no way of discriminating between trash and a good find. They might be useful for those on a very tight budget or as a starter but for the serious metal detecting enthusiast I'd generally recommend they be avoided.

4. Broad Band Spectrum (BBS)

Broad band spectrum metal detectors function using a broad band of signals, emitted in more than one frequency. Capable of emitting up to 17 different frequencies, broad band spectrum metal detectors offer good discriminating capabilities. Since they use a range of frequencies they can identify a target more accurately. They can detect at varying depths better than a single frequency detector.

Additionally, false signals from salt water beaches and ground minerals are reduced. BBS metal detector technology has now been phased out, but I've included it in the case of anyone buying an older second hand metal detector.

underwater metal detectors

What Can You Find With Underwater Metal Detectors?

Wherever people gather they lose things! People gather on beaches they lie on the sand and things fall out of their pocket and get buried by sand quickly.

The most common item of 'treasure' to be found will be coins. In beach environment these are most likely to be present day coins, old silver or gold coins will be an exceptional find on a beach.

Folks also swim in the ocean and a mixture of sunscreen and the cool water causing finger shrinkage means that rings can often slip off and be lost. Until found by you!

Of course, if the ring has any identifying marks that may identify their owner such as a name then all efforts should be made to return the ring to its rightful owner. However, in practice this is going to be rarely possible.

Underwater Metal Detecting Accessories

In addition to your detector there are a few basic accessories you should have.


These are essential to filter out background noise and hear the subtle signals that may otherwise be drowned out by ambient noise. Most detectors will come with a standard set of headphones, but of course you might want to upgrade from the basic set.


You'll need something to dig the sand around your target in order to locate your find.

Sand Scoop

A sand scoop will greatly assist you locate your discovery and speed up the process. A sand scoop is a simple sieve, fine enough to allow sand to pass but coarse enough to securely hold on to your find.


A simple pouch or utility belt is a useful accessory to hold your finds. You'd probably rather not fill your pockets with sandy finds.

Recahrge4able Batteries

There's nothing worse than your batteries running out of charge halfway through your session. Remember to carry some fully charged spares.


A pinpointer is an optional extra. Some people prefer them others prefer the sand scoop method. You'll certainly need a pin pointer when treasure hunting in soil so you may already own one. But for beach and ocean hunting a sand scoop is quicker and just as effective.

Metal Detector Bag or Cover

Since you'll have several items it makes sense to also purchase a metal detector bag or cover. This will keep all your things together and keep them protected.