The hand-held GEM-3 uses the same electronics and firmware as our GEM-2
ski, so its features and options are comparable. Because it is comfortable
to carry and has a field-swappable battery, extended surveys are no
It is available with 3 different diameters of sensing head: 30, 40 and
65 cm. The larger diameters provide more moment for greater depth
penetration, while the smaller diameters are better for localization and
Depending on the model, it can use up to 10 simultaneous frequencies from
30 Hz to
The GEM-3 produces inphase and quadrature
data at each frequency. Inphase data is sensitive to earth's electrical
conductivity and magnetic susceptibility. Therefore, over highly
conductive and/or magnetic soil, the inphase data is often too sensitive
to sensor height to be a stable detection indicator.
The quadrature data, however, are insensitive to the height variations
and, thus, provide reliable detection. The sum of all quadrature data is
an excellent detection indicator in magnetic and/or conductive geology.
Frequency programmability allows you to tailor detection to your
intended targets and environmental conditions. The frequencies can also be
programmed to mimic the response of other fixed-frequency instruments.