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Depending on the type of soil and other environmental factors, coins lost 200 years ago won’t sink on the ground more than 8 inches. So, coins don’t sink as deep as many people think. A mid-level affordable metal detector like the Garrett ACE 300 could easily detect coins at this depth. You do not need any fancy expensive model to do that.
The Garrett ACE 300 has a coin depth indicator that will tell you whether the coin is 2”, 4”, 6” or 8” deep. This depth indicator can work with other objects as well but it is designed for coins: a large object will appear shallower than it really is and vice versa.
In addition to that, the screen of the Garrett can identify the object before you even dig. It can tell you to except finding: a Penny, a Nickel, a Dime, a Quarter, a Half Dollar or a dollar along with other items (pull-tabs, rings, bottle caps…)
The sensitivity is adjustable. This is important because the higher the sensitivity the deeper you can hunt coins. But if you start hearing some chattering, lower it a little bit to avoid false signals.
The Garrett Ace 300 has different modes; one of them is the coin mode. But this not really important. Because to be able to go deeper, generally, you should pick the zero-disc mode. And you can see it on the screen too.
With such type of detectors, you can find civil war relics and coins before this date easily. Trying to find coins deeper isn’t worthwhile.
However, I will give you a guide to help you buy the best one for you and a second guide to get the most depth from the detector you have.
Which one can go deeper?
A metal detector with a larger search coil can go deeper, but the sensitivity may decline and pinpointing may become harder depending on the model.
When using low frequencies the coil could detect objects deeper. So pick a model with selectable frequency or multi-frequency.
The first one allows you to select a frequency to work with. And since you are looking for deep coins, choose low frequency. The second one uses many frequencies (low and high) at once.
The ground may contain some minerals and other stuff. The deeper you go, the more impurities will be in the way of the search coil. This stuff will create more noise and below a certain depth, you won’t be able to detect anything.
This is why ground balancing is crucial. If you’re a beginner you should stick with a metal detector with a preset ground balancing like the model mentioned above.
But, if you are an expert and you know what you are doing, you can adjust the balancing to fit the type of soil you are looking in.
This way video will compare the depth that could be reached by 3 classes of metal detectors when detecting objects with different sizes and compositions including coins. But, the test in video doesn’t take into account ground balancing.
How can you metal detect at a greater depth ?
The metal detector has a certain depth that it can’t go beyond. But, you still can push it to its limits by applying few tips.
In some cases, using headphones with good sound quality may help you to hear weaker beeps that you may have missed previously.
This depends on the sound quality of the onboard speakers of your metal detector and the noise in the surrounding area.
Walk slowly and make sure that you the swings overlap so that you do not miss any coin. The metal detector is a motion detector.
Which means that it cannot detect anything if is stationary. And, if you swing it too fast you may miss metal objects too. So it is up to you to find the optimum swinging speed which enables you to find items at a greater depth.
You can test this by laying the detector on a wooden table with the search coil over the edge. Then swing a coin at different speeds and different distances from the coil to find out which swinging speed allows you to go deeper.
Keep your search coil as a close as possible to the ground, about a half an inch is good. You don’t want to stick the coil to the ground to avoid damaging it. But, if your coil is protected by a cover, go ahead. This way you can detect coins a little bit deeper.
Adjust the discrimination to the minimum. That way the detector will be able to work deeper but you may end up finding a lot of trash. So increase the discrimination a little bit at your convenience.
It is a compromise to do in order to find the best discrimination for maximum depth and minimum junk.
Adjust the sensitivity as high as possible. The higher the sensitivity the deeper you can go. However, this means more noise. So you have to keep tuning it until you find the best one.
The depth a metal detector could reach depends on the size of the search coil. The larger the coil, the deeper you can detect.
If you want to extend the depth range of your metal detector, you can try NEL coils. They are super large and they can go really deep.
However, large coils are less sensitive to small objects. They aren’t the best choice for trashy areas.
They are heavier than the stock coils. Your arm will hurt you after swing it for a few hours.
There are also some external factors, which affect the depth that a metal detector can reach like the soil composition (contains or not minerals) and structure (compacted or aerated…).
Objects with higher conductivity are easier to detect even if they are deep. It depends also on the size of the coin. The larger, the deeper you can detect it.
The target’s shape and orientation have an impact over the depth it can be detected.
Circular metal objects like coins and rings could be detected deeper than thin and long objects like nails.
A coin that is laying flat could be detected deeper than a coin that is vertical.
If the target is buried in a soil with low mineralization, it can be detected deeper than a metal object buried in a highly mineralized ground.
Go coin hunting when the soil is wet. That way, you will be able to find objects deeper than what you use used to when the soil was dry. The wetter the better. If the ground is too wet, you may get some noise. Adjust the sensitivity until it fades out.
(I couldn’t find any reliable experimental data confirming the impact of the soil’s humidity on the depth range, this is something that many detectorists reported)
Conclusion
If you are looking to hunt deep coins. A metal detector like the Garrett ACE 300 can do the job easily. Since coins, left for a long period of time won’t sink more than 8 inches deep.
You can follow the tips that I mentioned above to able to find coins a little bit deeper (if there is any). And, if you want a better and more expensive detector, I hope the guide about the coil size, the frequency, the ground balancing… helps you.