Depth tests on the bottom of a freshly dug hole does not represent real search conditions and therefore are not accurate and also misleading.
These demonstrations exaggerate the result, making the metal detector appear far deeper than it is in reality, due to enhanced signal produced from the disturbed soil and hole.
The most accurate way to determine depth of a metal detector is by using a hand held drill and drilling a hole in the soil, keeping the hole size to a minimum and then compacting the soil as much as possible as demonstrated in the video below.
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Nexus Metal Detectors
