Did you ever experience that your metal detector beeped for no reason? There are a few reasons why your metal detector produces false signals. Electromagnetic Interference is one of them. What is Electromagnetic Interference actually in metal detecting?
Electromagnetic Interference happens when the electromagnetic field of the metal detector intersects with the electromagnetic field of another device. The effect of electromagnetic interference is that your metal detector gives false signals. The most common devices that cause electromagnetic interference are power lines, radio signals, a pinpointer and your mobile phone.
In this article, I will provide you with all the information you need to know about electromagnetic interference. By the end of this article, you will also learn how to prevent your metal detector from producing false signals caused by electromagnetic interference.
What is electromagnetic interference?
Electromagnetic interference occurs when the electromagnetic fields of two devices intersect, which can result in false signals from a metal detector. Common sources of interference include power lines, radio signals, pinpointer devices, and mobile phones.
You can identify electromagnetic interference with your metal detector when it emits irregular beeping sounds without a valid cause. Additionally, decreased sensitivity and background noise are signs of interference.
The level of interference can vary depending on the type of metal detector and the specific coil being used. Certain metal detectors may experience disruptions when detecting near power lines, while others may perform adequately under such conditions. We will delve deeper into this topic later in the article.
What kind of devices interfere with a metal detector?
Electromagnetic interference arises when two devices in close proximity generate electromagnetic fields. Consequently, numerous devices have the potential to cause such interference. However, there are several specific devices that commonly interfere with metal detectors.
The most common devices that interfere with your metal detector are electric power lines, other metal detectors, a pinpointer, cell phones, radar signals, electrical vehicles, a radio & tv broadcast signal and telephones lines.
The most common devices that interfere with your metal detector are electric power lines, other metal detectors, and pinpointers. It is crucial to be mindful of these factors during your detecting sessions.
Always remember to turn off your pinpointer after use, as many people tend to forget this step. Neglecting to do so can result in numerous false signals from your metal detector, causing unnecessary confusion.
Furthermore, maintaining a minimum distance of 4 meters between you and your detecting partner is essential to prevent mutual interference between the metal detectors. This ensures a smoother and more accurate detection process.
Even your cell phone can emit a minor electromagnetic field, which can potentially disrupt your metal detector’s operation. Consider switching it off if you notice continuous beeping or interference caused by your phone.
If you frequently find yourself detecting in areas with multiple interfering devices, it may be worth considering an anti-interference coil. In my blog about coils, I will provide comprehensive information about the different types available and guide you on selecting the most suitable one.
How do I know if my metal detector interferes with other devices?
There are two ways how you can check if your metal detector is interfering with other devices. The first way is to put your metal detector in the air and see if it beeps. The second way is to move your coil from the left to the right above a surface where no metal components are located beneath the coil and see if it beeps.
When you suspect that your metal detector is causing interference with other devices, there are several measures you can take to mitigate the issue. In the following subheading, I will explain these measures in detail.
How to prevent electromagnetic interference?
Luckily, there are some things that you can do to avoid electromagnetic interference. Firstly, you should use either a small coil or an anti-interference coil. Secondly, you should properly use the discrimination and sensitivity function. Last but not least, you should try to detect at the off-peak hours.
Use a small coil
If you experience that your metal detector interferes with other devices, you should consider to switch to a smaller coil. The reason for this is actually really simple. The larger the coil, the greater the emitted electromagnetic field.
This means that is it more likely that a larger coil reacts to the electromagnetic field of other devices. Therefore, you should choose a smaller coil!
Use an anti-interference coil
Besides the fact that it is a good idea to use a small coil, you can also choose to use an anti-interference coil. The main idea of this coil is that it reduces the amount of interference between your metal detector and other devices.
Adjust the sensitivity level
The sensitivity function of a metal detector is probably the most important setting that you have to adjust in order to avoid electromagnetic interference. The sensitivity level determines how strong your metal detector reacts to an electromagnetic field.
If you use a high sensitivity level, the metal detector will quickly respond to an electromagnetic field. If you use a low sensitivity level, the metal detector won’t quickly respond to an electromagnetic field.
If you experience that your metal detector reacts too quickly to other devices, you should consider to lower your sensitivity level. Try to choose the highest sensitivity level as possible, otherwise you will lose too much detection depth.
Use the discrimination function
There are some people that say that it is better to avoid the discrimination function when you want to detect in areas with a lot of electromagnetic interference. They claim that the metal detector is better able to distinguish the target’s electromagnetic field from the electromagnetic field of other devices without using this function.
This means that you should use the ‘’zero mode’’ on your metal detector. Keep in mind that this doesn’t work for all metal detectors. Therefore, you should figure out what works the best for your metal detector. You should also keep in mind that your metal detector reacts to all the metals when you use the zero mode.
Detect at the right time
To minimize electromagnetic interference, consider conducting your metal detecting activities during off-peak hours. During these times, such as late evening or early morning, many devices tend to generate less electromagnetic fields as they are not operating at their maximum capacity.
This can reduce the chances of interference and improve the performance of your metal detector.
Frequently Asked Questions
Yes, a mobile phone can interfere with a metal detector. This happens because a cell phone can emit a little electromagnetic field.
Basically, all devices that emit an electromagnetic field can cause electromagnetic interference. The most common devices are power lines, radar signals and telephone lines.
It is a good idea to use either a small coil or an anti-interference coil in areas with a lot of electromagnetic interference.