Just follow these steps.

Turn the stems lock nut clockwise until it loosens.

Lengthen or shorten.

If the detector is on, turn MODE Note: When you turn the mode switch to, the LOW BATT indicator flashes once.

Press the right battery compartment covers tab and slide the cover off in the direction of the arrow.

Extended high-volume listening can lead to permanent hearing loss.

You must move the object since you are not sweeping with the detector at this time.

If you cant, take the detector to your local RadioShack store for assistance.

The number of times that the currents direction switches each second establishes the frequency of the unit.

This wire acts as an antenna to pick up and amplify frequencies coming from target objects in the ground.

The polarity of the magnetic field is perpendicular to the coil of wire.

Each time the current changes direction, the polarity of the magnetic field changes.

This means that if the coil of wire is parallel to the ground, the magnetic field is constantly pushing down into the ground and then pulling back out of it.

The polarity of the objects magnetic field is directly opposite the transmitter coils magnetic field.

If the transmitter coils field is pulsing downward, the objects field is pulsing upward.

However, it is not shielded from magnetic fields coming from objects in the ground.

Therefore, when the receiver coil passes over an object giving off a magnetic field, a small electric current travels through the coil.

This current oscillates at the same frequency as the objects magnetic field.

The coil amplifies the frequency and sends it to the control box of the metal detector, where sensors analyze the signal.

The closer to the surface an object is, the stronger the magnetic field picked up by the receiver coil and the stronger the electric current generated.

Since most metals vary in both inductance and resistance, a VLF metal detector examines the amount of phase shift, using a pair of electronic circuits called phase demodulators, and compares it with the average for a particular type of metal.

The detector then notifies with an audible tone or visual indicator as to what range of metals the object is likely to be in.

Usually, you can set the level of phase shift that is filtered, generally by adjusting a knob that increases or decreases the threshold.

Radio Shack Metal Detector Instructions