Finding desirable objects while metal detecting can be difficult and is mostly up to chance and luck, but there are some things you can do to increase your likelihood of making an exciting discovery. One thing you can do is consistently and correctly calibrate your metal detector.
You should calibrate your metal detector at least once a year, although more frequently is better. Anytime you change terrain or your target object changes, you should recalibrate your metal detector to increase your chances of success.
In this article, I’ll discuss everything you need to know about metal detector calibration, including what it is, how often you should do it, and various factors that influence the calibration settings.
The Ideal Metal Detector Calibration Frequency: What is it and Why Does it Matter?
Calibrating your metal detector with the right frequency and correctly is one of the best ways to set yourself up for success when searching for objects. Calibrating a metal detector mostly involves checking your detector’s sensitivity or frequency, which allows you to detect what you’re looking for without wasting time and energy digging up trash or listening to constant chatter from your metal detector. Calibration also involves checking the discrimination.
You should calibrate your metal detector at least once a year, although I recommend doing a calibration every six months. You may want to calibrate even more frequently than biannually if you notice your metal detector frequently chatters or gives false signals.
I also suggest calibrating your detector if you’re changing terrains. Often, your metal detector needs adjusting if you’re switching from the beach to the forest, so you’ll need to calibrate.
Here’s how to calibrate your metal detector:
- Turn on the detector.
- Give the detector some time to warm up.
- Adjust your sensitivity according to your desired material.
- Change the discrimination according to your desired material.
- Pass a small piece of iron in front of the metal detector.
- Adjust the signal by turning the ground trimmer. Keep turning until the signal is clear and consistent.
A metal detector’s sensitivity controls its ability to pick up on specific types and sizes of metal. The higher and better the frequency, the more objects the metal detector can pick up, and the objects can be smaller.
The following table outlines the ideal frequency settings for various materials you’re likely to search for:
| Material | Sensitivity |
| Silver | 7 kHz |
| Copper | 7 kHz |
| Brass | 7 kHz |
| Gold | 15 kHz |
| Iron | 10 kHz |
| Nickel | 8 kHz |
| Aluminum | 8 kHz |
| Zinc | 10 kHz |
Various factors influence a metal detector’s ability to pick up on an object. These factors influence how high or low your frequency needs to be.
- The type of metal. Most metal detectors can find all kinds of metals, but some metals are easier than others for detectors to sense, especially if the sensitivity is turned down. Metals that are not good electrical conductors, such as lead, are harder for a metal detector to pick up on than good electrical conductors, such as aluminum and iron.
- How deeply buried the object is. The deeper the item, the harder it will be for the metal detector to sense it, and therefore the higher sensitivity the metal detector needs to be set at.
- The shape of the object. Smaller objects are more difficult to find unless the sensitivity is high. At some point, objects are simply too small for a metal detector to find them, even if they are made with metal with good electrical conductivity.
- The temperature of the environment. Environmental temperature can influence a metal detector’s performance and sensitivity setting. Therefore, if your climate experiences an extreme change, you should recalibrate your metal detector to ensure the sensitivity is still where it needs to be.
The other part of a metal detector’s calibration is its discrimination. Discrimination is a feature on newer metal detectors that allows you to set which metals you want the detector to look for and which metals you’d like to ignore. For example, you can set your metal detector up to look for silver and gold but ignore iron metal, tin foil, and steel, so you aren’t wasting time digging up bottle caps and pull tabs.
Most Pulse Induction metal detectors don’t have the discrimination feature, but most VLF (Very Low Frequency) metal detectors do. VLF metal detectors send alternating currents through the coil, which creates a transmit frequency that the machine sends into the ground. This frequency will send a signal to the machine if it reaches a metal.
Calibrating the discrimination differently empowers the machine to intervene with the signals and tells the alert system whether or not it should ignore the signal. Most metal detectors have the following modes:
- All metal. The all metal mode is essentially letting your metal detector give a signal for every bit of metal it picks up. If you’re a beginner, I suggest using this setting to get a better idea of what your detector sounds like when it finds certain metals, so you don’t miss out on some exciting finds.
- Coin mode. This discrimination setting is pretty self-explanatory. This is the best mode for you if you’re looking for coins. If you’d like more advice on finding coins, I recommend reading my article on the best metal detector settings for coins: These are the Best Metal Detector Settings for Coins
- Relic mode. Not all metal detectors have this option, but if you’re looking for jewelry or relics, this mode is a good bet. A relic is a broad term that includes most items from the past, including old coins and artifacts. If you’re lucky enough to find one of these objects, you might be unable to keep it.
- Prospecting mode. If you are exclusively looking for gold, this is the discrimination setting you’ll want to use. Many metal detectors don’t have this feature, but if you have an advanced detector or one that’s specifically designed to find gold, using this setting will increase your chances of finding treasure.
Calibrating your metal detector may seem like a hassle, but you’ll get better at it with practice, and it’s a small step that can greatly influence your metal detecting experience. Even cheap metal detectors with fewer settings benefit from regular calibration.
When You Should Use Discrimination
Altering the discrimination settings on your metal detector can be a huge help. Here are some scenarios in which you might want to calibrate your metal detector to alter the discrimination:
- You’re detecting an area with ferrous soil. Some soil has more ferrous material in it than other soil, which can overload your metal detector’s coil and cause lots of chattering. However, if you calibrate your metal detector and adjust the settings to ignore iron, the chattering will go down. If this doesn’t change how much chattering you get, you may have a faulty coil.
- You’re looking for something specific. If you have just one item you’d like to find, adjust your discrimination settings so you’ll only get signals for that type of material. You may miss out on other finds, but you’ll probably locate what you’re looking for much quicker. The discrimination setting is especially helpful if you’re looking for gold.
- You’re detecting an area with lots of trash. Public areas, such as playgrounds or carnival grounds, usually have plenty of treasures you can discover, but they also have lots of trash. You’ll probably want to calibrate your detector to seek out more desirable metals instead of iron, so you can avoid digging up nails and other bits of trash.
- You don’t have a lot of time. As mentioned above, not using the discrimination setting may result in you spending a lot of time digging up unwanted objects, including lots of trash. If you only have an hour or so in a specific area, you don’t want to waste any of your time and should adjust the discrimination setting.
- You’re an advanced detectorist. Beginner metal detectorists may benefit from hearing the different tones that indicate various metals, but if you’re advanced, you’ve moved beyond that need.
In these scenarios, it will save you time and energy to take the time to adjust your calibration settings before heading out to your detection spot.
Conclusion
Metal detectors should be calibrated at least once a year. Still, you’ll probably want to calibrate your metal detector more frequently than that, especially if you’re changing your terrain or your goals for what you’d like to discover have changed. Calibrating your metal detector involves adjusting the sensitivity and discrimination settings and the signal to give a clear and consistent sign when the machine detects something.
