Let’s talk about something really important in the world of metal detection: the frequency of a metal detector. It’s a topic that gets a lot of attention and is super significant.
The frequency of a metal detector tells us how many times the electromagnetic field goes back and forth each second. We measure it in hertz (Hz), which means the number of cycles per second. The average metal detector operates at a frequency of 14 kHz. This means that the electromagnetic field generated by the detector oscillates back and forth 14.000 times per second.
Metal detectors come in a variety of frequencies. Each frequency level has its own detection depth and can uncover different objects. Are you ready to dive into the world of detector frequencies? If so, keep on reading!
Introduction to metal detector frequencies
Basically, the frequency of a metal detector is all about how many times the electromagnetic field is sent and received in just one second.
To make it even clearer, take a look at the image below. It shows that a low frequency doesn’t send and receive electromagnetic fields as fast as a high frequency does.
What’s really cool about this principle is that you can choose what kind of targets you want to find by adjusting the frequency level. Check this out:
When you set the frequency to low, the electromagnetic fields can go super deep into the ground, which is perfect for detecting objects that are buried really far down. But if you crank up the frequency to high, the electromagnetic fields won’t go as deep, making it easier to spot objects that are closer to the surface.
Now you might be thinking, “Why not just stick to a low frequency all the time then?” Well, here’s the catch: using a low frequency has its downsides too. You see, a metal detector set to a low frequency isn’t as good at picking up small objects.
Sure, the electromagnetic field can go deep into the ground, but it might miss those tiny treasures you’re hoping to find. On the flip side, a high frequency is like a pro at detecting small objects because it’s super sensitive.
But wait, there’s a trade-off! A high frequency might be great for small objects, but it can’t reach as far down into the ground. It’s like having pros and cons for each frequency.
So, it’s all about finding the right balance. Sometimes you need that deep-penetrating power of a low frequency, and other times you want the high sensitivity of a high frequency to uncover those little gems hiding just beneath the surface.
To make it easier for you to remember, here’s a quick summary of the advantages and disadvantages of high and low frequencies.
Pros and Cons of a LOW frequency
- Deep ground penetration
- Good for detecting large targets
- Less sensitive for mineralized soil
- Less sensitive for interference
- Detects high-conductive targets
- Less sensitive for small targets
- Larger search coil needed
- Harder to distinguish targets
- Hard to detect low-conductive targets
Pros and Cons of a HIGH frequency
- Detects small targets
- Detects low-conductive targets
- Good for distinguishing targets
- Smaller search coil needed
- Too sensitive for mineralized soil
- Too sensitive for interference
- Limited ground penetration
- Difficult to detect large objects
Single-Frequency vs Multi-Frequency Detectors
In essence, there are two types of frequency metal detectors to distinguish. These are:
- The Single-Frequency Metal Detector
- The Multi-Frequency Metal Detector
The difference between these metal detectors is actually quite simple: the single-frequency metal detector has one (non-adjustable) fixed frequency, while the multi-frequency metal detector has multiple adjustable frequencies.
Most hobby metal detectors, such as the Bounty Hunter Tracker IV and the Garrett Ace 300, are single-frequency metal detectors. Generally, single-frequency metal detectors are also cheaper than multi-frequency metal detectors. Simply because they have less advanced technology.
Many people are fans of a multi-frequency metal detector because they can adjust the frequency based on their needs. This way, a detectorist can choose to use a high frequency to search for small objects like coins and a low frequency for large objects like a horseshoe.
To provide an overview of the differences between a single and a multi-frequency metal detector, I have created the table below.
| Aspect | Single-frequency metal detector | Multi-frequency metal detector |
|---|---|---|
| Frequency | One fixed frequency | Multiple adjustable frequencies |
| Customizability | Not adjustable | Adjustable |
| Object Detection | Good for small targets | Good for small and large targets |
| Soil conditions | Works well in clean soils | Works well in all types of soils |
| Price | Relatively cheap | Relatively expensive |
Single-frequency metal detectors comparison
Most metal detectors available on the current metal detector market are single-frequency metal detectors. However, there are numerous differences among these single-frequency metal detectors. Some of them are excellent options at a very attractive price.
In the table below, I have compared several popular single-frequency metal detectors. So, if you’re considering purchasing a single-frequency metal detector, I highly recommend taking a look at this.
Multi-frequency metal detectors comparison
Multi-frequency metal detectors are becoming increasingly popular among many metal detectorists due to the numerous advantages they offer compared to single-frequency metal detectors.
When considering a multi-frequency metal detector, it’s essential to choose the right one since these detectors can be on the pricier side (often twice as expensive as a single-frequency metal detector).
Based on my knowledge of metal detectors, I have created the following comparison table. Here, you can find some popular multi-frequency metal detectors.
What is the best frequency for a metal detector?
It’s difficult to determine the best frequency to use. It mainly depends on two factors:
- The type of soil you want to detect
- The type of target you want to search for
Let’s start with the type of soil. When detecting in soils with mineralization, it’s wise to use a lower frequency. This reduces the detector’s sensitivity to soil mineralization, resulting in fewer false signals.
In soils where interference from other devices is present, it’s also advisable to use a lower frequency. Based on my knowledge, I have prepared the table below, which shows the type of soil and the corresponding frequency that works best.
| Type of soil | High/Medium/Low frequency | Frequency level |
|---|---|---|
| Clean grounds such as fields or forests | High frequency | 15 – 20 kHz |
| Average soil conditions such as parks, lawns, or moderately mineralized soils | Medium frequency | 10 – 15 kHz |
| Soils with high mineralization, such as salty beaches or areas with abundant mineral deposits | Low frequency | 5 – 10 kHz |
The other factor is the type of target you want to find. If you’re searching for small targets like coins or thimbles, it’s advisable to use a high frequency.
On the other hand, if you’re looking for larger targets like a horseshoe or an iron rod, it’s better to use a lower frequency. In the table below, I’ve indicated the recommended frequency for each type of target you want to find.
| Type of target | Optimal frequency |
|---|---|
| Coin | 6 – 20 kHz |
| Medieval Thimble | 10 – 15 kHz |
| Jewelry | 15 – 30 kHz |
| Buckle | 6 – 12 kHz |
| Ring | 10 – 15 kHz |
| Bullet | 6 – 12 kHz |
| Military Button | 10 – 15 kHz |
| Gold nugget | 20 – 60 kHz |
| Iron | 2 – 6 kHz |
| Pendant | 6 – 12 kHz |
Finally, there’s one last factor to consider when determining the optimal metal detector frequency. And that’s the conductivity of a target.
In the table below, you can find the ideal frequency for various types of metals with different electrical conductivity.
| Type of metal | Optimal frequency |
|---|---|
| Iron | 5 – 10 kHz |
| Silver | 8 – 12 kHz |
| Gold | 20 – 60 kHz |
| Lead | 2 – 5 kHz |
| Stainless Steel | 15 – 30 kHz |
Metal Detecting Frequency vs Ground Mineralization
It’s quite common to encounter highly mineralized soils during metal detecting. It’s a real nightmare for most detectorists because the soil mineralization can result in false signals.
So, it’s extremely important to not only have the right sensitivity and discrimination settings but also use the appropriate frequency. In general, it’s highly recommended to use a lower frequency in these types of soils.
Using a low frequency will ensure that your metal detector won’t react as quickly to ground mineralization, reducing the production of false signals.
In general, it is recommended to use a frequency between 3 and 10 kHz. At this frequency range, most metal detectors are capable of distinguishing genuine targets from ground mineralization effectively.
Metal Detecting Frequency vs Electromagnetic Interference
In addition to ground mineralization, there may be situations where you have to detect in areas with electromagnetic interference. This simply means that there are other devices emitting an electromagnetic field, causing your detector to pick up those fields and produce false signals.
Just like in highly mineralized soils, it is advisable to use a low frequency in these situations as well. Try to use a frequency below 10 kHz.
You can often identify areas with high electromagnetic interference by the presence of power lines or antennas. These are frequently the devices that generate electromagnetic fields.
Does the size of the search coil affect the frequency?
There are many different types of search coils that can be used for a metal detector. They vary in size, shape, and design. Each type of search coil also has a different frequency.
Large search coils often have a low frequency, allowing them to detect deep objects. On the other hand, small search coils typically have a high frequency, making them more suitable for finding shallow objects.
In the table below, you can find various types of search coils along with their corresponding frequencies (disclaimer: there may be slight variations in frequency among search coils, but these are the most common values):
| Search Coil Size | Frequency range |
|---|---|
| Large search coil (11-15 inches) | 1 – 5 kHz |
| Medium search coil (7-10 inches) | 5 – 15 kHz |
| Small search coil (3-6 inches) | 10 – 60 kHz |
| Extra small search coil (1-2 inches) | 60 – 100 kHz |
How do I know the frequency of my metal detector?
If you already have a metal detector, it can be useful to know what frequency it uses. However, in most detectors, you can’t directly read the frequency from the display screen.
My advice is to consult the manual of the specific metal detector. It will state the frequency used by the metal detector. The manual can often be found online as well.
Additionally, you can also check the platform where you purchased the detector. Often, the product description will mention the corresponding frequency of the detector.
If none of these mentioned tips work well, I recommend visiting online metal detector forums and asking your question there. These forums usually have knowledgeable metal detectorists who can certainly help you out.
How to adjust the frequency of a metal detector?
Based on all the information you’ve gained from this blog, you may want to adjust the frequency of your metal detector (if you’re using a multi-frequency metal detector).
This varies, of course, depending on the metal detector, but as an example, I’ll use the Minelab Equinox 900. In general, you can easily adjust the frequency in the control panel (display screen) of the metal detector.
For the Minelab Equinox 900, you need to hold down the frequency button, which allows you to scroll through all the frequencies (4, 5, 10, 15, 20, 40 kHz). Based on this, you can choose your desired frequency.
The frequency button can be found on the control panel of the Minelab Equinox 900. It is located at the bottom right and looks like a symbol with two waves.
What is the best metal detector frequency for detecting gold?
Since gold prospecting is a popular activity among many detectorists, let me provide some additional attention to it. The main focus is often on finding small gold flakes, which can be quite challenging and requires a lot of patience, as well as the right metal detector settings.
Therefore, selecting the appropriate frequency is crucial to increase your chances of finding gold. Gold flakes are typically small and have poor electrical conductivity. This means that you need to use a relatively high frequency to detect them effectively.
It is recommended to use a frequency between 20 and 60 kHz for detecting gold nuggets with a metal detector. However, keep in mind that for larger gold pieces, you can also use a slightly lower frequency.
What frequency do pulse induction (PI) metal detectors use?
In addition to single-frequency and multi-frequency metal detectors, there is another type called a pulse induction (PI) metal detector. A pulse induction detector operates using a different technique compared to other detectors.
Instead of continuous wave transmission, it emits pulses and measures the time between those pulses upon receiving the signals. Generally, pulse induction metal detectors utilize an extremely low frequency, typically ranging between 1 and 5 kHz.
Due to this low frequency, pulse induction detectors often have significant detection depth and are suitable for finding gold in mineralized soils. However, one drawback of pulse induction metal detectors is that they tend to be more expensive compared to other types of detectors.
What is the average frequency of a very low frequency (VLF) detector?
Most metal detectorists prefer using a very low frequency metal detector (VLF) instead of a pulse induction (PI) detector. The VLF metal detector operates at an average frequency of around 15 kHz.
This makes the VLF detector an ideal choice for the average metal detectorist, as it can detect a wide range of targets, from coins and jewelry to horseshoes. It’s great because you can find all sorts of treasures with it!
What is the frequency range of the average multi-frequency metal detector?
In general, a multi-frequency metal detector operates within the range of 5 to 40 kHz. This means that the detector’s frequency range spans from 5 kHz to 40 kHz. However, it’s worth noting that there are detectors available with both lower and higher frequency capabilities.
Taking into account the wide variety of detectors available, I would say that the frequency range for metal detectors typically falls between 1 kHz and 100 kHz. Keep in mind that this range is not definitive and can vary depending on the specific make and model of the metal detector.
Frequently Asked Questions
The frequency of a metal detector impacts its sensitivity as it determines the detector’s capability to detect and react to various sizes and types of metal targets. Higher frequencies tend to be more sensitive to smaller targets, whereas lower frequencies excel at detecting larger and highly conductive targets.
The frequency of a metal detector influences its capability to distinguish between different metals based on their conductive properties. Higher frequencies are effective for detecting low-conductive metals like gold, while lower frequencies excel at detecting high-conductive metals such as copper or silver. Discrimination settings further aid in metal differentiation.
As a beginner metal detectorist, you want to maximize your chances of finding objects and also learn how to use the detector effectively. Therefore, it’s advisable to stick with an average frequency. Aim for a frequency of around 15 kHz.
Is the frequency of a metal detector indicated on the display?
This depends on the type of metal detector you’re using. With single-frequency metal detectors, you often can’t read the frequency directly on the display. On the other hand, with multi-frequency metal detectors, you can usually see the frequency displayed on the screen.