Metal Detectors Depth – Facts Rumors and Falsehoods
More false information has clouded the issue of detection depth than any other topic since the first beeper and there are some good reasons why. The depth that a metal detector will find a metal object will change drastically due to the differences in soil moisture and type. Benchmark field tests are just not possible because of the wide number of variables. You can start an argument faster over this topic than any other thing in metal detecting. Differences in mineralization, hot rocks, iron ore, or other environmental factors will always affect the outcome of a test but the one thing that we want our detector to do is detect deeper, ever deeper.
Probably over 80% of all objects we want to dig are only a few inches deep but many believe that just a little deeper and they can find the “really old” coins. In some areas its true but many areas just don’t have many old targets to find anywhere or any depth. If we take a hard look at deeper coins then we should ask ourselves do we really want to dig holes over a foot deep in the nice lawn? Do we desire greater bragging rights or are we really ready to dedicate ourselves to the effort of extracting deep finds? If we are wanting a deeper detector just because we are not finding much then it will be a disappointment because what we really need is more experience with the detector we are using. More whistles and bells cannot replace detecting experience. The Metal detector manufacturers could get rich fast if that were true.
Deep targets are often not identified by the detector because target ID detectors generally drop out of target identification range at about 7-9 inches. Better detectors may give “some” indication of depth but this feature needs to be improved if it is to be useful. If you are walking through a moderately trashy park and picking up several objects every step, will you take the time to test each one to see how deep it is? You might, but I won’t. My experience has told me that I look at the depth after I have a coin acquired on the meter and when I am walking through many targets I just don’t take the time to measure each one because the most effective use of my time is to move fast and collect the shallow coins. If your meter will not identify a deep object will you dig all of them? The answer is only if you are detecting in an area with a high expectation of valuable finds like relic hunters or hunting where very old coins are found regularly. Other than that you may do it for a while out of curiosity but you will tire of it when your targets turn out to be rusty nails and tin cans.
Most of the time if you are searching clean areas for deep signals you can use a no motion detector set on maximum sensitivity and using a large coil and quality wired or wireless headphones. Digging everything is quite a job if you are digging deeper objects but all part of the game. Some detectors claim different tone ID’s or meter recognition but most of the really deep objects in my experience are just a whisper of a tone. I find that sometimes I find objects deeper in wet sand than heavy clay or dry sand. The gold prospector who uses a detector certainly needs all available depth and sensitivity to tiny nuggets he can get, and many of the areas that he will want to prospect are highly mineralized which reduce the depth on most detectors. New technologies appear to improve the detection depth in heavy mineralization and as always it depends on where you want to hunt for the choice of detector.
Controversy continues over air tests for depth comparison, and obviously mineralization is not a factor but benchmark air tests provide a quick comparison of metal detectors that you can perform at the store, in the field, or at the club. There is also another air test that I do and that is to determine what the detector is tuned for, gold or silver. I take my gold ring and check the depth on it and then checkout silver coins. It is obvious that it will be stronger at one end of the spectrum or the other. I have discovered it means something to me when I can lay down my detector and air test it compared to the hot new beeper with chrome bumpers and my old box wins! I can understand that under certain conditions like heavy mineralization the air test may not show true, however it is the ONLY fair benchmark that I can use to get an idea of a units depth capability other than field tests on my hunting grounds using different detectors. So far my old air tests have proved fairly accurate for my test purposes and when the new chrome beeper really beats mine then I will consider it for an upgrade someday
What you want is true information about different detectors in “your backyard”. Who cares if it works well in Alaska if you are in South Florida? What you need to do is get together with others from your local club and ask them to bring their detectors to the club meeting where you have a test plot ready to test each one for depth. Your test plot can be in in any signal free spot around the yard somewhere where you have buried several deep coins. This is a simple comparison can provide valuable information if you have determined to upgrade to a deeper beeper.
It isn’t long before the first complaint we hear from the new detectorist is “I need a deeper metal detector“. That is often a symptom of something else entirely, perhaps they have selected a poor site to detect, or their lack of experience is preventing them from finding good targets. Recently I had a very old detector to tune and set it up correctly and I was shocked to observe how very deep it would find targets. True it lacked the whistles and bells of todays high end detectors but it would do the job admirably. One problem with todays detectors is that manufacturers are greedy and realize that many detectorists will pay high prices for new metal detectors. This practice generally ends up with detectors that are so loaded down with add-on features that the detector becomes heavy and eats a full charge of batteries almost every hunting trip. In my estimation the best features of a detector are: lightweight, easy on batteries, weather-proof, stable, requires little interaction for mode switches and adjustments, and a durable detector, one that can take a few bumps now and then. I also like a good user interface that gets the message across without trying to impress me with how sophisticated it looks. One direction that I think the industry should go is to provide only a LCD that will indicate the accurate VDI or, in other words the numeric value of the target. The industry should remember that a large, clearly readable display, should be preferred over small readouts that are hard to see even in good light and with good vision. This should be accomplished without adding weight to the detector such as heavy, bulky, old fashioned meters. I think unless the depth readings can be improved that they should consider a sound feedback instead of meter as indication because when you are swinging and walking you rarely have time to check the depth on objects but if you had a “ping” that indicated deep object, you might reconsider digging it.
The adolescent arguments over deep metal detectors will continue forever, but it takes time and experience to begin to realize which features are really worth the expense of a new detector. Some folks go at new detectors like a kid at a pie eating contest and often suffer regret in the days to follow, so you might take some sage advise and take the time to discover what you really want and really need when you think you need to dig’em deeper.