Want to Maximize Your Metal Detecting Finds? “Do the Math!”

Garrett ATpro Metal Detector

I realize going in that some parts of this article will be considered “controversial” by some detectorists who let their emotions rule their head when it comes to how they metal detect.  I think we all start out that way when we first begin detecting but, in my case, I now have had nearly 50 years of metal detecting experience that has taught me to get past that obstacle and increase my finds by “Doing the math.”

What do I mean by “Doing the math?”  The simple answer is… the more high-value targets you dig per hour of detecting, the better finds you are going to have.  Tied tightly to that piece of math is another mathematical equation…  the more square feet of ground you cover per hour of detecting, the more high-value targets you are going to find over the long haul.  Now, add to that another piece of math…  the quicker you recover a target from the soil, the more ground you will cover per hour of detecting which means you will find and recover more high-value targets.

There is actually all kinds of math involved in being a very successful metal detectorist so let’s continue to explore more of it.  Here is another example of what I am talking about…  the more gear that you carry when you metal detect, the sooner you will tire out which means the less time you will spend detecting in a day (especially true for senior citizen detectorists)… which means… the less high-value targets you will find and recover.   Also… if you are someone who believes in routinely digging everything, you will dig a lot of low-value targets… per hour of detecting which means, overall… you will dig considerably LESS high-value targets. The flawed logic used to justify digging everything is, I might miss something good.  The truth is… you will miss “something good” if you dig everything… a lot of “somethings good,” in fact.  You will spend most of your time digging low-value targets when, if you ignored them, you would find more high-value targets by the end of the hunt than you would have.

Here is another way math controls the amount of your detecting finds…  The bigger the hole you dig when recovering a target, the longer it will take you to recover the target and… fill your holes.  And that means… you will find and dig less total number of targets per hour… and that means… you will find less high-value targets.

The math of time is always a factor in how many finds you make in a day.  If you are a late starter, like a hunting buddy of mine, who can’t get himself out of bed for an early start and shows up around noon, you lose a lot of hours in a day that you could have been detecting and digging targets.  This means, again, that you will find fewer targets of high value over the long haul.

The math of distance traveled to a hunt site is also a big factor in how many good finds you make.  In this case, the math can either work for you or against you.  Example:  You can be at a local park near you in just a few minutes of driving and for a day’s hunt might come back with a handful of new money and maybe a silver coin or ring or another old coin or two.  Or… you could drive a hundred miles to hunt, say, an old reunion/picnic ground, long abandoned, that you found by research and though you lost two hours of daylight getting there, it contains a lot more high-value targets so in the time left you make no new money finds but come up with say three dozen old and silver coins for the day’s hunt.   Distance traveled to reach a detecting site has to be balanced against the potential of good finds… in other words… you put the odds in your favor… and that… is more math!

And speaking of research… the traditional average of research versus “in the field” metal detecting has been for a lot of years… and still is… a ratio of 3 to 1… three hours of research for every hour spent swinging your metal detector.  Most detectorists these days spend less than an hour of research for every hour spent detecting, so… their odds of finding an un-worked site full of great finds are much lower than those who do put in the time researching mentioned above.  Again… the math is in your favor when you properly research for sites.  When you use days of inclement weather or hours of darkness to do your research, you don’t waste any good weather detecting days and that also helps put the math in your favor. 

Another way that many metal detectorists fail to “do the math” is in how they swing their detector.  Three common errors that rob them of finds are as follows: 

Metal Detecting Pendulum Swing
Do the math… waste 2/3rds of your swing with the “pendulum” and anyway you add it up, it means fewer good finds.
Metal Detecting Tips
Here you see the principle illustrated of how a flat swing can increase your good finds by as much as a factor of 3.
  1. The “pendulum swing. This is where the coil moves like the pendulum on a grandfather clock.  It is only near the ground right directly in front of the detectorist and comes way off the ground at the end of the swing on both the left and right sides.  By not keeping the coil flat on the ground and moving it in a half-circle from left to right.  Most of the swing is wasted as far as covering ground.  Do the math… the less ground covered with each swing… the fewer good finds at the end of the day.  
  2. Holding the coil several inches above the ground while swinging it.  For every inch of height above the ground the coil is swung an inch of detection depth is lost.  If you swing your coil 3” above the ground you will lose 3” in depth detection on high-value targets, which means… you will find less good targets during the time you detect. It also means you will lose a lot of older coins and artifacts that were in that three inches you could have detected by keeping your search coil barely touching the ground as you swung it. 
  3. Having the front of your coil tilted upward as you swing, thus having only the rear of the coil detecting metal at maximum depth possible.  Again, this error robs you of good finds by limiting the amount of ground you could be covering at maximum depth as you swing your detector.  
  4. Not considering the magnetic field pattern of your search coil will result in your not overlapping your swing enough and causing you to miss many deep targets right on the bottom point of your detection ability. Naturally, factors like soil mineralization, how hard it is compacted, and the amount of moisture in the ground will also affect the depth you get on coins but failing to realize that the shape of the coil’s magnetic field means that while you may detect a target across the entire width of the coil at shallow depths, you are only scanning a very narrow area of the soil beneath you at the tip of your detection capability… only an inch or two wide with each swing.  So… if you do not advance only an inch or two with each swing on good sites, you will miss detecting a high percentage of the deep coins and other high-value small targets present (See accompanying diagram showing the shape of the magnetic detection fields of both 2-D and Concentric search coils).   
Understanding Search Coils Metal Detecting
The deeper targets are usually the better targets and the older ones. Without a close overlap of your detector swings you will miss a number of them… the math does not lie!
Searchcoil Tips Metal Detecting
The angle of tilt here on the search coil on the left is exaggerated for effect. No amount of tilt on the search coil is an effective way to detect as it will cause you to miss good targets.

Also… do not hunt with your elbow bent. This will eventually result in a painful condition in your elbow joint we call “detecting elbow.”   Again… do the math… if it becomes too painful to swing your detector, you will detect less and that… will result in fewer good finds.

Improve Metal Detecting Swing

Don’t make any of these mistakes when you swing your search coil… it just doesn’t “add up.”

I was surprised at a recent metal detecting event I sponsored for my social media group to see veteran detectorists with several years of detecting experience still making these mistakes and robbing themselves of a lot of good finds. So… even veteran metal detectorists can end up failing to “do the math” and robbing themselves overtime of a lot of good finds.

Now, let’s tackle the “controversial” part of this article where my comments will likely stir up strong emotions in some reading this.  Please know that I am not doing this just to be controversial… far from it.  It is just that sometimes we need to hear the things we don’t want to hear because, even though they make us uncomfortable and we disagree, they are nonetheless true.  I would be remiss if I did not address this important issue involving the pinpointing of targets that hardly anyone ever writes about.   

Most detectorists these days are “addicted” to hand-held pin-pointers… so much so, that a number of them even try to use them to dig their finds out of the holes they open with them.  Those so addicted, never… and I do mean never… learn how to accurately pinpoint a target with their metal detector search coil using a process called “de-tuning.”   I have watched various metal detectorists root around in their holes or the too-large dirt piles from the holes with their hand-held pin-pointers for as long as 10 minutes trying to locate their targets.  Do the math… if it takes 5 to 10 minutes to recover a target that means when you factor in the time spent swinging your detector… even in a target-rich environment…  no more than maybe 3 or 4 high-value targets an hour can be located and recovered by the detectorist which means they will usually find and dig no more than maybe 25 to 35 targets for a full day of detecting.  My average locating and digging of targets without using a hand-held pinpointer is from 10 to 15 per hour.  Do the math.     

Have you ever timed yourself on how many targets you locate and dig per hour in a target-rich environment?  If your answer is no, then you are not aware of how many good finds you could be cheating yourself out of by taking too long to make a target recovery.

When it comes to pinpointing, this is another way that I “do the math…” I do not use a hand-held pinpointer because I do not need one.  I learned to pinpoint a small target dead-on with just my detector coil way back in the ’70s using a technique we call “de-tuning” and even now, in my mid-seventies in age, it still only takes me 45 seconds to a minute and one half to pin-point, dig and recover a high-value target.  That means I spend a lot more time swinging my detector in a day and that… means more high-value target finds over the long haul.  I also save the expense of having to buy and/or replace a handheld-pinpointer which means it costs me less to go metal detecting… another example of how doing the math pays off.

Civil War Metal Detecting Advice

The author points to an early 1800’s brass button located and recovered in less than 2 minutes without a hand-held pinpointer.  Note the small size of the hole dug to recover it.  The depth on the target was about 7”.

Let me give you a real-life example of how the math I have mentioned already in this article came into play on one of my recent Civil War relic hunts.

The site was on the famous Civil War battlefield of Perryville, KY… one of the 20 largest battles of the entire Civil War.   It was a cow-pasture that had seen bitter fighting during the battle that went on nearly all day.  Charges were made across that ground by both sides and hundreds of thousands of bullets and scores of cannonballs and shells had been fired there.

When we arrived to hunt it for the first time, my hunt-buddy, whose permission it was, informed me…  “Don’t think you are going to find a lot of relics… this place has been hunted by a lot of good hunters for 35 years.  You will be lucky to find a bullet or two.”  I informed him that I would not be happy with that result and had the goal of finding at least 20 Civil War artifacts that day.  He laughed at me and told me I was crazy.  He was using an XP Deus metal detector that he had paid over $2000.00 for while I was using a considerably less expensive Garrett AT Pro.  He had been detecting with the Deus for over two years and this was my first time to have the Pro on a Civil War relic hunt, although I had been metal detecting several decades longer than he had. 

We selected opposite sides of this sloping pasture with a big valley in its center and high ground on both sides and started detecting.  At noon we met in the middle and he told me he had found nothing.  I had 8 artifacts from the battle.  He could not believe it and got really upset and said that I was “very lucky” and that he was going to follow me around for the afternoon part of our hunt. 

Well, at the end of the day, even following me around and intruding into my detecting space whenever I found an artifact, he still only had managed to find four artifacts and I had 18.  It just about drove him crazy and he accused me of having the artifacts on me when we got there.  I explained that, no, that was not the case… his problem was that he was taking so long to pin-point his targets and was then digging holes much bigger than necessary to recover his targets and then… spending more time chasing the target around in the big piles of dirt he excavated with his hand-held pinpointer, instead of first narrowing down which part of the big dirt piles his target was in with his metal detector.  You should always check the dirt dug out of the hole first with your detector before you go rooting around in it with a hand-held pinpointer if you insist on using one.

The process of “de-tuning” a search coil, I mentioned above, involves using a certain technique with the pin-pointing button on your detector that effectively shrinks the coil down to the size of about a quarter with the hot spot being right in front of where the shaft connects to it.  You can then, not only pinpoint the location of the target with extreme accuracy, you can actually determine the size of your target and trace the shape of the bigger ones before you even start digging them. This process is easier to demonstrate than it is to describe but once it is mastered with a little practice you just can’t beat it for giving you more info on your targets before you dig.   

Here is now “de-tuning” related to my relic hunting buddy’s not doing the math… his holes were averaging 16” in diameter and at least a foot deep while mine was 6” in diameter and 8” to 10” deep on average.  I usually got the target out of the ground in the first plug that I dug.  I would check the plug with my detector to make sure the target was in it and then lay the detector coil down by the hole. I then divided the plug and ran half in front of the top of my search coil to see if the target was in it.  If not, I knew it was in the other half of the plug and divided that in half and checked for a signal again.  This way, I soon had the small piece of dirt with the target in my hand and could quickly locate it and get it in my pouch… and… get back to swinging my detector. The smaller dig hole also meant less time to fill it back in… plus… where I had dug a target was much harder to see when I was finished than his… which looked like someone had filled in a foxhole.   My average recovery time on a target that day was a minute and a half… even on the deep targets. His was from 10 to 15 minutes per target.  The math defeated him that day… because… he did not consider it important.  I did… small wonder I got more artifacts. I was doing the math… he was not.   

Metal Detecting Civil War Tips
Doing the math results in more great finds like these.

Another way the math gave me more success that day… and the next three hunts we did there as well, was that I had done extensive research on what happened on that piece of ground during the battle and I knew that there had been so many artifacts lost there that even with all the previous detecting that had gone on in that pasture, there would still be hundreds of artifacts… if not thousands… still awaiting discovery.  In the four hunts we did before the owner died and we lost the permission, I found over 100 Civil War artifacts, upping my totals to well over 25 per hunt after that first one.  So having done the math on how much battle activity had taken place there while my hunting buddy had not, kept me from being “psyched out” by the fact that it had already been hard hunted by the time we got there. 

People, in general, are not comfortable with change but the great metal detectorists of the ’70s and 80’s all got over letting their emotions guide their detecting and learned math… which will always increase the odds of your finding more high-value targets.

I keep the math in my favor by carrying a minimum of gear weight and using my search coil to pinpoint my targets, carefully choosing my sites and weighing the distance traveled to get to them against the potential for making great finds.

I also use the math to help compensate for advancing old age and the problems it inevitably brings in kneeling down on the ground and then getting back up again using “high-mileage” knee joints.  I do not get down on the ground… I remain standing and just bend over to recover my targets from the dirt… this is much easier on my old knees and much quicker in terms of target recovery for me.  So… don’t let your emotions rule your metal detecting technique… do the math and you too will find and recover more high-value targets.

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  1. Excellent article Dorian. IMHO you left out one part that I believe you have mentioned to me over time……you don’t spend a lot of time looking at the target, or spraying with water, and using a brass or tooth brush to admire whatever the target was. We can ALWAYS look at the prize later, after the trip. I wholeheartedly agree with all you have said in this article, and if people will take heed and practice what you shared here, they will become better at recovering history. Once again, Dorian has knocked it out of the park!

  2. I am the opposite. I do a good job of pinpointing with my coil. I usually use my pinpointer on deeper targets. I average a 45 to 60 second retrieval. I usually find good items deeper. I hunt a lot of farm fields. If the targets are 6 inches or less I can usually retrieve them in 30 seconds. I do agree, covering more ground and quicker retrieval are keys to finding more.

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