Electromagnetic Interference (Emi) - Teknetics G2+ Owner's Manual

ELECTROMAGNETIC INTERFERENCE (EMI)

You are likely to encounter electromagnetic interference (EMI) when using your G
2+
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.
EMI can cause a metal detector to chatter spontaneously, to lose sensitivity for no apparent
Symptoms of Electromagnetic Interference
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 EMI include: overhead electric power lines, underground power lines,
Common sources of Electromagnetic Interference
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 G is
2+
specifically designed to enable you to workintothenoise. 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
Theprimaryreasonmetaldetectorsprovideasensitivity(gainand/orthreshold)control,
interference. Some users are reluctant to reduce sensitivity out of fear of losing depth.
is so that users can reduce sensitivity in order to eliminate response to electrical
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. TheThresholdcontrolonlyappliestotheAllMetalMode.
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