Data Collection
© Radiodetection 2016
39
RD1100 Operation Manual
Figure 8-10: Varying the Gain
Soil Cal
Soil calibration (also known as velocity) is a parameter used to ensure that measured depths
are accurate. The best way to ensure this is by using the hyperbola-fitting method, since it is
based on data collected in the area.
Crossing linear targets like pipes or cables at a 90 degree angle produces a hyperbola suitable
for soil type calibration. The Soil Cal value obtained will be used to compute a depth estimate of
a target.
NOTE: These depths will be
incorrect
if the soil type is calibrated on a target hyperbola
produced at an oblique angle, rather than 90 degrees.
Once you have a hyperbola on the screen from a subsurface target, press
Soil Cal
. The menu
at the bottom of the screen will change, giving you the option of either specifying a Soil Type or
adjusting the Soil Cal using the hyperbola-fitting method (Figure 6-11). These options are
explained as follows:
Soil Types
– If there are no targets to calibrate to, and you know the type of soil, press
this button to vary between the following mediums, with the pre-set Soil Cal value shown
in brackets
o
very wet (60)
o
wet (80)
o
moist (100)
o
dry (120)
o
very dry soil (150)
o
air (300)
NOTE: you cannot “apply” and accept the
air
value. This is only to fit the hyperbola to
determine if it is an air wave (Section 7.5)
