Teknetics Gamma 6000 Owner's Manual page 18

OPERATION and CONTROLS
GROUND BALANCING
When manually ground balancing, try to "feel out" a spot on the ground
to make sure there is no metal present. In order to avoid locking onto
metal, the detector will not ground grab where the GROUND setting is
less than 40. Where the ground reads less than 40, the ground value is
displayed as "--", and manual ground balancing is required.
To perform the Manual Ground Balancing operation, do the following:
1. Select the GROUND GRAB mode
The legend GROUND appears near the top of the screen.
The present ground balance setting is displayed (0-99).
2. Physically pump the searchcoil and detector up and down over
the ground. Lift it about 6 inches above the ground and lower it
to within 1 inch of the ground, about once or twice a second. You
are trying to balance the sound as described on the top of page 19.
a. If the detector balances, use this setting as a starting point for
manual balancing.
b. If "--" is displayed press
3. While pumping the coil, press
balance setting.
The range of ground balance settings indicated on the display range
from 0 to 99; however, each displayed number spans about 10 pad
presses of the
settings change with each step; there are a total of 1000 different settings.
The scale at the upper-right of the screen indicates the AMOUNT
of magnetic mineralization. The searchcoil must be in motion to
measure this. The most accurate measurement is obtained by
pumping the searchcoil, as in the Ground Grab procedure.
The indicators are as follows:
VL = Very Low Mineralization
L = Low Mineralization
M = Moderate Mineralization
H = High Mineralization
The two-digit GROUND setting number displayed at the center of the
LCD indicates the TYPE of ground mineralization.
Some typical ground mineralization types are:
0 -10 Wet salt and alkalis
5 - 25 Metallic iron. Very few soils in this range. You are probably
over metal.
26-39 Very few soils in this range -occasionally some saltwater beaches
40-75 Red, yellow, and brown iron-bearing clay minerals
75-95 Magnetite and other black iron minerals
18
continued
and buttons. The actual internal ground balance
until you find the desired setting.
or to change the ground
cont.