Ground Balance - Whites TDI SL Owner's Manual

Ground Balance

This control is used to balance out
the signal from ground mineralization.
There is an
OFF
runs in straight PI mode with no
ground balance.
To ground balance TDI the
control must be set to
Conductivity
in order to hear both conductivity tones. Set the
mid-point or until the audio just begins to chatter. Pump the
search coil up and down from about one inch off the ground up to
6-8 inches above the ground while listening for a change in the
audio. If the GB is too low, the audio will have a high tone when
the coil is lowered to the ground; if the GB is too high, the audio
will have a low tone. Adjust the
imal audio changes. For most moderate mineralization, this will
be around "8". A simple technique is to start with the GB set
intentionally too low (say, 5), then pump the coil and increase the
GB until the high tone begins to transition to a low tone.
If the
Pulse Delay
need to re-adjust the
begin to hear ground noises (false signals) as you sweep the coil
you should check the ground balance.
There are some cases where a particular target will fall
exactly on top of the ground balance point and TDI will not be
able to detect it at all. Targets that are close to the ground bal-
ance point may have their response shifted if the
control is adjusted. For example, a given target may have a
ance
low conductor response with GB=9 but a high conductor
response at GB=5.
Turning the Ground Balance to the
the ground balance and TDI will run as a straight PI detector.
This gives a slight improvement in depth but, of course, will
respond to mineralization and eliminates the ability to discern
conductivities.
TDI SL
Owner's Manual
position for which TDI
control is changed, you will probably
Ground Balance
Page 12
Target
ALL
Ground Balance
setting. In addition, if you
OFF
to about the
Gain
control for min-
Ground Bal-
position disables