10
THE BASICS OF METAL DETECTING (continued)
5. EMI (Electromagnetic Interference)
The searchcoil produces a magnetic field and then detects changes in that
magnetic field caused by the presence of metal objects. This magnetic field
is susceptible to the electromagnetic energy produced by other electronic
devices. Power lines, microwave ovens, lighting fixtures, TVs, computers,
motors, etc., all produce EMI which can interfere with the detector and
cause it to beep when no metal is present, and sometimes to beep
erratically.
The GAIN control lets you reduce the strength of the magnetic field, and
thereby lessen susceptibility to EMI. You may want to operate at maximum
Gain, but the presence of EMI may make this impossible, so if you
experience erratic behavior or “false” signals,
reduce the sensitivity,
by
adjusting your GAIN and THRESHOLD controls.
HEADPHONE JACK
The detector has a 1/4” headphone jack on the left side of the housing.
When a headphone is connected, speaker audio is disabled. The
headphone jack has a rubber plug that will keep dirt and moisture from
entering the control box.
USING HEADPHONES
Using a detector with headphones facilitates
detection of the weakest signals and also extends
the battery life.
It also allows you to hear subtle changes in
the sound more clearly, particularly if
searching in a noisy location. For safety
reasons, do not use headphones near
traffic or where other dangers are
present. This device is to be used with
interconnecting cables/headphone
cables shorter than
three meters.
Headphone
Jack with
plug installed
