Instruction manual
Coil Options
The X-TERRA range is a unique series of metal detectors in that they can
literally switch operational frequencies by simply changing to a dierent
frequency coil. In the previous model series, the X-TERRA 30 was capable
of using the 7.5 kHz coils. The X-TERRA 50 could utilize either the 7.5 kHz
or the 18.75 kHz coils. And the X-TERRA 70 could utilize the 7.5 kHz,
18.75 kHz or the 3 kHz coils. The newer released 305 can utilize the
7.5 kHz or the 18.75 kHz coils. And both the 505 and 705 can use all three
frequencies.
Currently there are eight coils available for the X-TERRA. Five are
waterproof and three are water resistant.
Water resistant: May be splashed, washed, used in drizzling rain, or
moved through wet grass. Must not be submersed under water.
Waterproof: Submersible to one meter. Ideal for shallow water wading
and gold prospecting in shallow streams .
• The stock coil (except for the 705 Gold Pack) is a waterproof 9-inch
Concentric, at 7.5 kHz. Also available in the waterproof 9-inch
Concentric is a high frequency 18.75 kHz and low frequency 3 kHz.
• There are two waterproof 6-inch coils available. A small Concentric
at 7.5 kHz and a small Double-D at 18.75 kHz.
• The stock coil in the 705 Gold Pack, is the 18.75 kHz water resistant
elliptical Double-D, measuring 5” x 10”.
• And there are two water resistant 10.5-inch Double-D coils. One at
7.5 kHz and the other at 18.75 kHz.
In a nutshell, larger coils will detect larger targets deeper than a
smaller coil, but smaller coils are more sensitive to small objects.
Higher frequencies are better suited for lower conductive targets, such
as gold. And lower frequencies are better suited for higher conductive
targets such as silver and copper. A Concentric coil will hunt deeper
than a comparably sized Double-D coil, in moderately mineralized
soil. But due to the design characteristics, Double-D coils are the best
application for highly mineralized soil. And, a Double-D coil separates
targets better than a comparably sized Concentric.
44Understanding your X-TERRA - Coils