Emi (Electromagnetic Interference); Headphones; Basic Of Metal Detecting - Teknetics Delta 4000 Owner's Manual

THE BASICS OF METAL DETECTING (continued)
The searchcoil produces a magnetic field and then detects changes in that

5. EMI (Electromagnetic Interference)

magnetic field caused by the presence of metal objects. This magnetic field
that the detector creates is also 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 SENSITIVITY control lets you reduce the strength of this magnetic field,
and therefore lessen its susceptibility to EMI. You may want to operate at
maximum strength, but the presence of EMI may make this impossible, so if
you experience erratic behavior or "false" signals, reduce the sensitivity.
HEADPHONE JACKS
The detector has a 1/4" headphone jack on the left side of the housing.
When the headphone jack is connected, speaker audio is disabled.
USING HEADPHONES
Using a detector with headphones facilitates detection of the weakest sig-
nals and also extends the battery life.
It also allows you to hear subtle changes in the sound more clearly, particular-
ly 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
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