SCINTREX ENVI-MAG, Manual

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Operating displays
ENVI-MAG Manual
A3-19
Instrument
Parameter Description
MODE
The mode is fixed to “search.” The text srch. is
displayed as a reminder only.
DUR
The measurement duration.
You have a choice of 0.5, 1 or 2 seconds. The selection
depends upon the accuracy you want and the speed at
which you will collect data.
The longest duration gives the highest precision, but you
will have to survey at a slower pace.
TUNE
FIELD
The value of the Earth's ambient magnetic field in the
survey area.
For best performance the tuning field should match the
ambient field as closely as possible, at least to within
+/- 1000 nT.
A map showing the approximate field intensity on the
Earth's surface can be found in Section B: Applications,
Figure B1-4: on page B-4. The values shown can be used
as a staring point, and applied equally to the Total-field
sensor or the Gradiometer sensor.
AUTO
TUNE
A “yes/no” toggle that controls the automatic tuning
function.
It is independent for the Total-field sensor and the
Gradiometer sensor.
The tuning value is updated after each reading in
preparation for the next one.
Auto tuning is particularly applicable if large variations of
the ambient field are encountered over longer distances.
Fixed tuning may be more appropriate in areas of large
cultural electrical noise, or very narrow, but large,
anomalies. These may pull the tuning away from the desired
frequency to that of the interfering frequency or to tuning
field values greatly different from the background values.
As the setting of this parameter depends upon your
particular survey conditions, it is not possible to suggest the
best setting. The mode should therefore be established by
experimenting. However, in general, it is more applicable to
use fixed tuning for the
site characterization
and
drum
location
configurations.