How far can a metal detector detect is always a question for many. Most people who are not familiar with this device think it can detect very high depths regardless of the ground condition. However, several factors affect how deep a metal detector can sense metal in the ground.
The accepted depth a metal detector can detect is a relationship to the size of the metal detector coil diameter. So, a 12 inch diameter coil can detect 12 inches deep. Other factors such as: size of object, type of soil and the detectors sensitivity also contribute to depth of detection.
The detector’s frequency and discrimination also affect its ability to detect metal buried deep.
If you are new to using metal detectors, there are some tips that you can check out so you can use your device correctly. However, you need to remember that laws cover this practice, which you need to know before you start detecting and digging.
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A metal detector has a search coil that transmits an electromagnetic field into the ground to detect buried metals. Any targets reached by that electromagnetic field are energized, causing them to send their electromagnetic fields. Then, the detector’s search coil will then receive the retransmitted field and produce noise to inform you that it detected a target.
However, how far a metal detector can detect is always a question.
The truth is that there are no exact figures to answer this question. But several factors can affect the depth that your device can reach when detecting metals.
- The size of the target detected
If your metal target is large, the metal detector can detect it deeper than the smaller ones. The reason is that larger metals have more surface area. For this reason, it causes more disruption in the electromagnetic field created by the metal detector’s search coil.
Additionally, the device can detect circular targets buried deeper as they also possess more surface area.
- Type of soil
The type of soil you are detecting metal from can significantly affect the depth of detection. If you are detecting from mineralized soil, your metal detector will probably face some issues.
Soil mineralization happens when there is a high amount of metallic particles and minerals present in the soil.
So, if you are looking for metals buried in this type of soil, your detector will find it difficult to find what you seek. Such is because mineralized soil generates a magnetic response when metal detectors detect it.
One soil type leads to something called “Hot Rocks” which is highly mineralized soil.
Moreover, how far a metal detector can detect from mineralized soil will depend on the soil’s mineral level. The higher the mineral level there is, the shallower your metal detector will detect.
- The metal detector’s sensitivity
The sensitivity level of a metal detector depends on its manufacturer. For instance, the Garret Ace 250 has eight sensitivity settings. For this reason, it has better target precision and deeper reach.
Metal Detecting Tip: Selecting the correct sensitivity is critical. Learn more about what sensitivity is and how to set it. How to set the sensitivity on a metal detector
But generally speaking, the size of the search coil directly influences how deep your device can detect. If your detector has a large coil, the more detection depth it will have. But it will also have less sensitivity to small targets.
- The detector’s frequency
One thing that differentiates one metal detector from another is the frequency it operates at. The operating frequency is the number of ground-penetrating EM or electromagnetic waves the detector can transmit every second.
Metal Detecting Tip: I’m often asked about the best frequency for metal detectors so I wrote up this article – Best Frequency for Metal Detectors
Moreover, this factor also affects how far a metal detector can detect.
Manufacturers measure detector frequencies in kHz or kilohertz. So, if your metal detector states that it has a frequency of 7kHz, it can transmit 7,000 electromagnetic waves per second.
Many of the metal detectors on the market have frequencies ranging from 7kHz to 25kHz.
They also operate under either single-frequency or multi-frequency. Low-frequency detectors are ideal for detecting deeply buried, large, and highly conductive metals. Meanwhile, multi-frequency detectors are more sensitive to small and less conductive metals.
How far a metal detector can detect will also depend on its discrimination. This term describes the machine’s ability to differentiate metals accurately based on their magnetic properties and electrical conductivity.
Metal Detecting Tip: One of the biggest technology improvements is discrimination on metal detectors. Read all about it here – How to Set the Discrimination on Metal Detectors
If your detector discriminates against unwanted objects, it will detect metals buried deeper, such as coins. (source)
3 Tips to Using a Metal Detector Correctly
People often use metal detectors for two reasons — to find lost items or as a hobby. But if you want to find objects buried in the ground, you need to know how to use metal detectors the right way. Knowing how to use your device correctly will affect how far a metal detector can detect.
That said, here are three effective metal detecting techniques:
Apply Preset Search Modes
If you are not sure how to use your metal detector’s adjustable and advanced settings for maximum target detecting, the preset search modes are available for you. These presets have the right parameters to help you detect a particular object. You can also use them for metal detecting in a specific place.
You will often see these search modes labeled as:
- Relics or Artifacts
- Coin and Jewelry
Create Your Search Profile
There are times when presets will not work well. Of course, manufacturers cannot always predict the suitable search modes for your site. Fortunately, some detectors allow users to create their search mode and save it for future use.
In the long run, you will develop your knowledge and skills about metal detectors. Once you have enough knowledge, you can set the best sensitivity, discrimination, and ground balance settings to improve your detector’s performance. Knowing these advanced settings can also enhance how far a metal detector can detect.
The Right Way to Sweep
Sweeping your metal detector is the best skill you need to master if you want to use your device the right way. Sweeping or swinging is the act of moving the detector’s coil side to side when searching for targets.
Metal Detecting Tip: Use the right sweep technique – means OVERLAPPING.
Moreover, the best way to search objects using metal detectors is to sweep them slow and low. It would help if you overlapped your sweeping pattern to ensure that the detector is not missing any ground. Also, you should never tilt or lift the coil parallel to the ground as this action could affect how far a metal detector can detect. (source)
What You Need to Know Before Using a Metal Detector
While metal detecting is a mere hobby for many people, some laws cover it. These laws vary from one state to another. So, before you start digging, you need to ensure that the government allows metal detecting in the area you are in.
Moreover, Federal law does not allow metal detectors within the US federal properties and national parks. It is also important to note that you should never hunt for targets in historical and archeological areas.
Meanwhile, national forests allow metal detecting, rock collecting, and gold panning even if you don’t ask for permits. But the best thing to do is always to check and ask the office of the local park rangers to be sure.
In addition, the officials you need to contact to ask for permission before metal detecting will depend on the site. If you plan to hunt at a park, asking permission from local officials or park rangers will allow you to know your restrictions. Similarly, you need to get permission from landowners if you are planning to hunt on private property. (source)
Check Out These Spots for Your Next Metal Detecting Trip
- How Metal Detectors Work, Mine Lab, https://www.minelab.com/knowledge-base/getting-started/how-metal-detectors-work/ Accessed September 2, 2021.
- Simon Owen, How To Use A Metal Detector Like An Expert Detectorist, Tech Metals Research, https://www.techmetalsresearch.com/guide/how-to-use-a-metal-detector/ Accessed September 2, 2021.
- Simon Owen, Metal Detecting Laws You Need To Know Before You Go, Tech Metals Research, https://www.techmetalsresearch.com/guide/metal-detecting-laws/ Accessed September 2, 2021.