Coil Shape
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Round (Concentric) |
Elliptical (Concentric or DD) |
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Reliable technology
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Less expensive
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Broader sweep pattern over the ground
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Narrower target response for better pinpointing
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Let you search closer against things like trees, fences, etc.
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Internal Coil Structure
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Concentric |
DD |
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Large transmitter coil/smaller receiver coil in the same plane
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Searches deep in the center of the coil diameter; the outside of the coil doesn't search at full depth
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Symmetry helps to minimize electrical drift due to time and temperature
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Better discrimination on shallow targets and flat iron objects
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Overlapping D-shaped transmitter and receiver coils of approximately the same size
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Searches almost the whole diameter of the coil at full depth
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Greater depth in mineralized soil
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Broad sweep pattern
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Narrower target response
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Coil Size (8" round or 10" elliptical are standard size)
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Smaller |
Larger |
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Lighter
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Easier to pinpoint with
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Superior target separation (important in trashy areas)
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More sensitive to smaller targets (important in gold prospecting)
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Allow covering more ground with each sweep
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Increased depth on medium and large size targets
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Coil Size by Activity
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Activity |
Size |
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Coin Shooting |
Smaller coils offer greater precision. |
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Relic Hunting |
Larger coils' extra depth is important for older objects (usually found deeper). Relic hunters usually hunt in more remote areas with less trash, so advanced target separation isn't as necessary. |
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Beach Hunting |
Larger coils deliver best ground coverage for large areas. |
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Gold Prospecting |
Smaller, elliptical coils are precise and very sensitive. |
