Ground Balancing - Fisher F19 Owner's Manual

GROUND BALANCING

What is Ground Balancing?
Why do I need to Ground Balance?
All soils contain minerals. Signals from ground minerals are
often tens or hundreds of times stronger than a buried metal object.
The magnetism of iron minerals, found in nearly all soils, causes one
type of interfering signal. Dissolved mineral salts, found in some soils
are electrically conductive, causing another type of interfering signal.
The mathematical term for describing these differences is Phase.
Phase varies with the types of minerals present in the
soil.
Ground Balancing is the process by which the metal
detector cancels the unwanted signals coming from the
ground minerals while still detecting the signals from
buried metal objects. This is accomplished by
matching the detector's ground balance setting to
the phase of the ground signal.
When the detector is calibrated to the soil, the
result will be deeper target detection, quieter
operation, and more accurate target identification.
How to Ground Balance your detector:
Ground Balancing procedure with the Ground Grab
BALANCING (GG) touchpad.
1. Turn the detector on and set GAIN at the 12:00 position.
2. Click on the right knob to the ALL METAL Mode.
3. Rotate the THRESHOLD control knob to the point where you hear a slight
background hum.
4. Sweep searchcoil across the ground to find a clear patch of ground with no
metal present.
5. Press and hold the Ground Grab
(GG) touch pad, and pump searchcoil over the clean ground. See illustration
above.
Pump searchcoil from within 1" of ground to 6"- 8" above ground.
6. When the GND PHASE settles down to only 1 or 2 numbers in variation,
release the GND GRAB button while still pumping the searchcoil. Note that
the audio response to the ground changed and "Evened Out" when you
released the button. Also note that the GND BAL value changed. After
balancing, you can hunt in ALL METAL... or return to Disc Mode.
The most accurate GND PHASE value is the value displayed when "pumping" the
searchcoil over the ground in an area free of metal.
® COMPUTERIZED GROUND
® COMPUTERIZED GROUND BALANCING
Ground Balancing continued on next page
Pumping coil
to ground
balance with
COMPUTER-
IZED
GROUND
BALANCING
button.
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