Discovery3 Metal Detector
(630-3008)                 Fine Tuning                Faxback Doc. # 17727

Once you become familiar with how your metal detector works, you can fine 
turn it to make it less sensitive to interference and more selective in
what it finds. For example, you can make it tune out undesirable objects
and tune in precious metals, such as having it distinguish between iron and
gold.

ADJUSTING SENSITIVITY

Use SENSITIVITY to adjust the detector's sensitivity to conditions that can
cause it to respond erratically. For example, broadcasting antennas and 
power lines can cause false signals.

Although SENSITIVITY does not affect the detector's sensitivity when the 
toggle switch is set to ALL METAL, the target ID and depth readings might
be erratic if the sensitivity is set too high when the toggle switch is set
to DISC.

Rotate SENSITIVITY clockwise to increase, or counterclockwise to decrease
the detector's sensitivity. Always set SENSITIVITY as high as possible
while minimizing "ghost" signals.

ADJUSTING DISC/NOTCH

You can set DISC/NOTCH so the detector distinguishes between junk and 
valuable metal objects, and only detects the types of objects that you want
to search for.

Using DISC

With POWER/mode set to DISC and the toggle switch in the left (DISC)
position, the control functions as a standard variable discriminator. As
you rotate DISC/NOTCH clockwise from its full counterclockwise position, it
rejects iron, foil, nickels, pull tabs, and screw caps (in that order).

Using NOTCH

When you set POWER/mode to NOTCH with the toggle switch in the left (DISC)
position, DISC/NOTCH functions as a variable notch rejection window. Then
you can adjust DISC/NOTCH to reject (or "notch out") selected types of pull
tabs or other trash.

For example, many types of gold rings are rejected along with nickels, but 
you can eliminate some pull tabs without rejecting nickels.

NOTE:  Some pull tabs or tab pieces cannot be distinguished from nickels
       and gold rings.

To set the DISC/NOTCH position, use a pull tab or other object of the type
you want to reject.

1.  Adjust DISC/NOTCH to FOIL.

2.  Slowly turn DISC/NOTCH clockwise until the detector emits no sound.

NOTE:  Check a nickel to be sure the Discovery3 still detects it.

With DISC/NOTCH properly adjusted, the Discovery3 detects nickels while 
rejecting pull tabs.

Using AUTO NOTCH

With the toggle switch in the left (DISC) position and POWER/mode set to
AUTO NOTCH, the detector rejects most trash items and emits a low tone (for
gold and nickel) or a high tone (for copper, silver, and brass).

Expect some targets to be junk items, even if the detector emits a tone. 
Besides nickel, other items that might emit a low tone include foil, some 
pull tabs, and small gold rings. Besides copper and silver, other items
that might emit a high tone include brass and medals.

You can use DISC/NOTCH to widen the spectrum of discrimination. For
example, as you turn DISC/NOTCH clockwise, the detector rejects zinc
pennies.


(JC/all-11/02/95)