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QUICK-START DEMONSTRATION
I. Supplies Needed
• a Nail • a Zinc Penny (dated after 1982)
• a Nickel • a Quarter
II. Position the Detector
a. Place the detector on a table,
with the searchcoil hanging over
the edge.
Or better, have a friend hold the
detector, with the searchcoil off
the ground.
b. Keep the searchcoil away from
walls, floors and metal objects.
c. Remove watches, rings and
jewelry.
d. Turn off lights or appliances,
whose electromagnetic emissions may cause interference.
e. Pivot the searchcoil back.
III. Click on detector with the left knob. Set the Gain at the
12:00 position for this demonstration.
IV. Click the right knob to the left to the DISC setting.
V. a. Wave the nail over the searchcoil.
b. Press
+
repeatedly, while continuing to wave the nail.
• Notice the change in sound.
• Sound changes from a HIGH tone to V.C.O. tones (see
page 25).
VI. Wave each object over the searchcoil.
Sweep coin flat and parallel to the searchcoil. This is how
you will usually find them buried.
a. Notice the tones and 2-digit target IDs for each object.
b. Motion is required.
Objects must be in motion over the searchcoil to be
detected in this mode.
VII. Press the
+
button several more times until the Disc value on the
display
=
60.
VIII. Wave the nail over the searchcoil.
a. The nail will not be detected
b. The nail has been “discriminated out.”
Quick-Start Demo continued on next page
ELECTROMAGNETIC INTERFERENCE (EMI)
You are likely to encounter electromagnetic interference (EMI) when using your Gold
Bug DP metal detector. It is important that you recognize EMI and take appropriate
measures to deal with it. This will prevent you from giving up on a worthwhile search
site, or from returning a properly functioning detector for repair.
Symptoms of Electromagnetic Interference
EMI can cause a metal detector to chatter spontaneously, to lose sensitivity for no apparent
reason, or to cause a periodic wobbly audio sound. What you hear will depend on what
operating mode you are using, the detector’s settings, and the source of the electrical
interference. The most common manifestation is spontaneous chatter.
All metal detectors are susceptible to EMI, but they vary in what kinds of interference
affect them. In a given environment some metal detectors may be affected by EMI
whereas others may not.
Common sources of Electromagnetic Interference
Common sources of EMI include: overhead electric power lines, underground power lines,
other metal detectors, telephone lines carrying electronic data, computer systems, electric
fences, old CRT-based televisions, cell phones, CB and emergency communication
radios, thunderstorms, fluorescent lights, metal vapor lamps, military aircraft with electronic
warfare countermeasures turned on, electric motors, VLF military communications systems
and automobile ignition systems. At home, in a store, or in an urban environment, there
may be several different sources of interference present simultaneously.
All metal detectors generate a certain amount of internal electronic noise. The Gold Bug
DP is specifically designed to enable you to work into the noise. Experienced users,
striving for maximum depth, often adjust the machine to search with a constant audible
background sound, and then listen through that noise for the sound of real targets.
Stricter regulations in recent years have cut down on interference from electric light
dimmers and auto ignition systems. However there has also been a proliferation of
VLF-UHF wireless communication systems (cell phones, Bluetooth, wi-fi, etc.), which
often affect metal detectors. Overall, the potential for electromagnetic interference is
greater than it was just a few years ago.
Modern high-end metal detectors are a lot more sensitive than older units; this also
increases your detector’s vulnerability to EMI beyond what you may be accustomed to
with an older detector. Metal detectors are by their nature designed to detect magnetic
fields, and electric current always produces magnetic fields.
Coping with Electromagnetic Interference
The primary reason metal detectors provide a sensitivity (gain and/or threshold) control,
is so that users can reduce sensitivity in order to eliminate response to electrical
interference. Some users are reluctant to reduce sensitivity out of fear of losing depth.
At reduced sensitivity settings, you may lose some depth, but at least you can still
search. The Gain and Threshold knobs control the sensitivity and are your first
line of defense against EMI.
The Threshold control only applies to the All-Metal mode.
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