How deep do metal detectors go?
Here's a question we get asked all the time and the usual response is "it all depends on the metal detector being used and the type of ground being detected."
However, there is a good rule of thumb when it comes to most off the shelf metal detectors: a typical metal detector can usually detect an object in ideal conditions like the size of a small coin at the depth of the size of the search coil being used, ie: a detector with a 6" search coil would typically detect a small coin-sized object to around 6" in depth.
There are a lot of variables when it comes to determining the possible depth capability of metal detectors. One of the biggest factors determining depth is the size of the object. while a small coin, nail or pull tab may not even register at deeper depths, things like buried pipes/sprinkler heads, soda cans, or old metal toys can often be detected at much deeper depths than the size of the coil being used as larger metal objects are much easier to detect than smaller objects using the right configuration on your metal detector.
Using a bigger coil usually offers more depth, many brands like minilab, Garrett, and Nokta Makro offer much larger coils than what's usually included in the box as after purchase upgrades, but remember, bigger isn't always better and it depends on the locations you usually hunt to determine the size of the search coil used. A large search coil is actually a nightmare to use in high trash areas where cans, pull tabs and other metal litters are prevalent.
Other determining factors for a metal detectors depth include:
Believe it or not, the weather often plays a huge role in metal detector depth capabilities. Usually, slightly damp or moist soil will often provide substantially more depth than dry and dusty soil in the middle of summer. You should expect maximum depth from your metal detector in spring and fall, as summer usually presents more challenges to metal detectorists, like hard, undiggable soil, and swinging heavy machines can become quite tiring in warmer/humid weather.
Metal detector frequency options and configuration:
Another factor that's unique to each metal detector is its operating frequency, a good rule of thumb is the lower the frequency the better depth the metal detector can achieve whereas the higher frequency the better the machine will perform at finding smaller objects at shallower depths. Most modern metal detectors operate between 12 kHz and 18 kHz, a good all-around setting that offers the ability to detect a broad range of depths and sizes.
Metal detector's sensitivity options and configuration:
getting the maximum depth out of a metal detector usually includes a combination of frequency and sensitivity settings. to achieve the maximum depth you would want to use the high sensitivity option however this will be a fine balance depending on the machine, max sensitivity can sometimes cause erratic behavior so dialing in the sensitivity to where you achieve stability and depth will be unique to the metal detector you are using. Start on high and adjust down in small increments and find the combination of settings that work best for you.
At BigBoysHobbies we sell metal detectors for all types of detecting, from extreme depth nugget hunting like the Minelab GPZ 7000 to waterproof multi-frequency machines and jack of all trades like the Minelab Equinox 800, if you have any questions please don't hesitate to contact us and as always, happy hunting!