Choosing The Right Coil For The Job - Minelab GPX 5000 Instruction Manual

Choosing the Right Coil for the Job

There are five main things you should consider
when deciding which coil is best for your
terrain and target:
Coil Size and Depth
A larger coil will typically find targets buried
deeper in the ground but they can be less
sensitive to smaller targets. A smaller coil is
typically more sensitive to small targets, but
does not go as deep as a larger coil.
Mineralisation
A Monoloop coil will often have improved
performance over a Double D coil but can be
more difficult to Ground Balance and therefore
possibly more noisy. A Double D coil is often
more stable in heavily mineralised areas.
Terrain and Vegetation
A small coil can be easier to manoeuvre
through thick scrub or rough terrain. A smaller
coil is also a lighter weight than a larger coil.
Discrimination
In areas where discrimination is required a
Double D coil is necessary for Iron Reject to
work. In high trash concentrations a smaller
coil is preferable.
Search Pattern
A Double D coil will typically provide a 'blade-
like' detection pattern from the toe to the
heel of the coil, which gives excellent ground
coverage. A Monoloop coil has a detection
field that is typically cone shaped, which
requires overlapping of sweeps to ensure
thorough ground coverage.
Note: Third party coils and accessories are
also available. These are not manufactured,
warranted or supported by Minelab. Please
note that after market coils used with a GPX
Series detector in some Soil/Timings settings
such as "Fine Gold" and "Enhanced" are likely
to either not work or produce significant levels
of spurious signals from mineralised soils.
85