Fisher Labs Gold Bug Pro, Gold Bug Owner's Manual
OWNER’S MANUAL
If you do not have prior experience with a metal
detector, we strongly recommend that
you:
1) Adjust the Gain to a
low setting in the
event of false
signals. Always
begin use at a reduced
Gain level; increase Gain
only after you have
become familiar with the detector.
2) Do not use indoors. This detector is for
outdoor use only. Many household
appliances emit electromagnetic energy,
which can interfere with the detector. If
conducting an indoor demonstration, turn
the Gain down and keep the searchcoil
away from appliances such as computers,
televisions and microwave ovens. If your
detector beeps erratically, turn off
appliances and lights.
Also keep the searchcoil away from
objects containing metal, such as
floors and walls.
3) Use a 9-volt ALKALINE battery only.
Do not use Heavy Duty Batteries.
2
TABLE OF CONTENTS
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-6
Batteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Quick-Start Demo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-9
Headphones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Basics Of Metal Detecting . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-11
Ground Minerals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Trash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Identifying Buried Objects . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Size and Depth of Buried Objects . . . . . . . . . . . . . . . . . . . . .11
EMI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Operation and Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Control Knobs
Off / On / Gain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Disc / All-Metal / Threshold . . . . . . . . . . . . . . . . . . . . . . . . . .14
Touchpad Controls
GG / Pinpoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
+
and - . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Operating in All-Metal mode
Ground Grab (GG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Setting the Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Unwanted Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Sweeping the Searchcoil . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Reading the Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Target Scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Operating in Discrimination mode
Ground Grab (GG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Setting the Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Gain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Disc Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Unwanted Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Sweeping the Searchcoil . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Using Pinpoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Reading the Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Discrimination Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19-20
Ground Balancing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21-23
Ground Balancing Technical Info . . . . . . . . . . . . . . . . . . . . . . . . . .24
Target Display & Audio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25-26
Gold Prospecting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27-28
Hot Rocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
Electrical Interference (EMI) . . . . . . . . . . . . . . . . . . . . . . . . . . .30-31
Search Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
Target Pinpointing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
Optional 11”DD Searchcoil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
Treasure Hunter’s Code of Ethics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
Device Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Back Cover
DEVICE SPECIFICATIONS
Mechanical: S-rod with electronics housing on rod, 3-piece breakdown
construction, nonmetallic telescoping lower rod, adjustable position
arm rest
Weight: 2 lbs, 8 oz with battery installed
Standard searchcoil: 4.7 inch (12.3 cm) closed-frame round biaxial,
waterproof
Batteries: Single 9 volt rectangular alkaline
Operating principle: VLF induction balance
Operating frequency: 19 kHz, crystal controlled
Reactive overload: 10,000 micro-cgs (with standard searchcoil)
Resistive overload: 1,200 micro-cgs (with standard searchcoil)
Ground balance range: From ferrite to salt water inclusive
Discrimination ground suppression: Combination of 2
order methods
Target ID ground suppression: 3
Battery life: 15+ hours on good quality alkaline
Operating temp range: 14 to 122 degrees F (-10 to +50 C)
Operating humidity range: 0 - 90% noncondensing
TREASURE HUNTER’S CODE OF ETHICS
• Always check Federal, State, County and local laws before searching.
• Respect private property and do not enter private property without the
owner’s permission.
• Take care to refill all holes and do not leave any damage.
• Remove and dispose of any and all trash and litter found.
• Appreciate and protect our inheritance of natural resources, wildlife and
private property.
• Act as an ambassador for the hobby; use thoughtfulness, consideration and
courtesy at all times.
• Never destroy historical or archaeological treasures.
• All treasure hunters may be judged by the example you set; always conduct
yourself with courtesy and consideration of others.
Introduction to the Gold Bug Pro
The New Gold Bug Pro is unique among gold prospecting metal detectors for
its combination of high sensitivity to small gold nuggets and its versatile
function as an all-purpose treasure detector.
The controls and features are tailored to gold prospecting, including a
sophisticated ground balancing system, separate control over signal gain and
threshold, and a unique discrimination control system. These features also
make for a great relic-hunting detector, especially when the Gold Bug Pro is
outfitted with the optional 11” DD searchcoil. While the Gold Bug Pro makes
for a highly competent coin-shooting detector, its user interface and features
are not specifically designed for this purpose. As a coin-shooter, you will
notice that the Gold Bug Pro exhibits slightly lower sensitivity to highconductivity coins, like a U.S. quarter; this is a result of its specialized design
to emphasize sensitivity to small low conductivity metals like
gold nuggets.
The Gold Bug Pro is outfitted with a small 5” searchcoil as standard equipment
since this searchcoil construction is best-suited to finding gold nuggets. You
may be familiar with other metal detectors which have larger searchcoils,
generally in the range of 8 to 10 inches in diameter. Large coils are designed
to cover the maximum amount of ground efficiently and for the deepest ground
penetration. Small searchcoils, intended for gold prospecting, are designed for
precision. The Gold Bug Pro’s small DD searchcoil makes pinpointing easier,
fits into small spaces where gold is often hidden, is better suited to penetrate
highly mineralized soils where gold is frequently found, and has the highest
possible sensitivity to tiny gold nuggets.
Congratulations!
Congratulations on your purchase of the new Gold Bug Pro metal detector. The newly
designed Gold Bug Pro has been custom designed to find the smallest gold nuggets,
but unlike other specialized gold prospecting detectors, it can also be used for relic
hunting and coin shooting too.
Whether you use your Detector in the backyard, at the shoreline, in the mountains or
fields afar, your investment will let you experience the excitement of searching for yet
uncovered treasures and give you hours and years of outdoor enjoyment. Out on your
own or with a group, places to use your Gold Bug Pro are unlimited as buried treasures
can be as near as your doorstep or as far as you wish to travel.
This manual has been written to help you get optimal use of your detector, so we hope
you will read it thoroughly before your first outing and will also refer back to this manual
from time to time to reinforce features and methods as you become more proficient in
the field.
Happy Hunting from Fisher Research Labs!
3
4
TERMINOLOGY
After you have identified a target using Discrimination mode,
press-and-hold the PINPOINT button to identify the target’s exact
location. This technique can yield more information about the target’s
shape and size and also find its exact location to facilitate extraction.
Pinpoint as follows:
1.
Position the searchcoil just barely off the ground, and to the side of
the target.
2. Now move the searchcoil slowly across the target; you can locate
it by the sound. The target is located directly under where the
sound is loudest.
Narrow It Down:
1.
To narrow the response further, position the center of the searchcoil
near the center of the response pattern, but not directly over the
center.
2. Release the PINPOINT button.
3. Press-and-hold PINPOINT button again.
4. Repeat this narrowing procedure to narrow the field of detection
further.
Note: Depth indication is less accurate
SEARCHCOIL DRIFT
If you plan to use the PINPOINT mode for
continuous searching, realize that drift will
occur
over
time,
causing
the detector
to gain or lose
sensitivity. Periodic
retuning of the detector
is required to minimize
drift; release and press
PINPOINT again to retune.
The following terms are used throughout the manual, and are standard
terminology among treasure hunters.
ELIMINATION
Reference to a metal being "eliminated" means that the detector will not
emit a tone, nor light up an indicator, when a specified object passes
through the searchcoil’s detection field.
DISCRIMINATION
When the detector emits different tones for different types of metals, and
when the detector "eliminates" certain metals, we refer to this as the
detector "discriminating" among different types of metals.
Discrimination is an essential feature of professional metal detectors.
Discrimination allows the user to ignore trash and other undesirable
objects.
RELIC
A relic is an object of interest by reason of its age or its association with
the past. Many relics are made of iron, but can also be made of bronze
or precious metals.
IRON
Iron is a common, low-grade metal that is an undesirable target in certain
metal detecting applications. Examples of undesirable iron objects are
old cans, pipes, bolts and nails.
Sometimes, the desired target is made of iron. Property markers, for
instance, contain iron. Valuable relics can also be composed of iron;
cannon balls, old armaments, and parts of old structures and vehicles
can also be composed of iron.
FERROUS
Metals which are made of, or contain, iron.
PINPOINTING
Pinpointing is the process of finding the exact location of a buried object.
Long-buried metals can appear to the eye exactly like the surrounding
soil, and can therefore be very hard to isolate from the soil.
PULL-TABS
Discarded pull-tabs from beverage containers are an especially
bothersome trash item for treasure hunters. They come in many
different shapes and sizes. Pull-tabs can be eliminated from
detection, but some other valuable objects can have a magnetic
signature similar to pull-tabs, and will also be eliminated when
discriminating out pull-tabs.
GROUND BALANCE
Ground Balancing is the ability of the detector to ignore, or "see through" the
earth’s naturally occurring minerals, and only sound a tone when a metal
object is detected. The Gold Bug Pro incorporates proprietary circuitry and
programming to eliminate false signals from severe ground conditions.
TARGET PINPOINTING
ASSEMBLY
Assembly is easy and requires
no tools.
●
1 Loosen both Locking Collars by rotating 100%
counterclockwise.
●
2 Insert the Middle Stem into the S-Rod and
click Silver Button into hole.
●
3 Position the lower stem with the silver button
toward the back.
Using the bolt, one rubber washer, and
knurled knob, attach the searchcoil to the
lower stem.
●
4 Press the button on the upper end of the
lower stem, and slide the lower stem into the
middle stem.
Adjust the stem to a length that lets you maintain a
comfortable upright posture, with your arm relaxed at
your side, and the searchcoil parallel to the ground in
front of you.
●
5 Wind the cable securely around the stems.
A loose or moving cable can cause false signals.
●
6 Connect cable plug to housing.
Do not twist the cable or plug. Turn knurled locking
ring only. Use minimal finger pressure to start the
threads. Do not cross-thread. When the locking ring is
fully engaged over the threaded connector,
give it a firm turn to make sure that it is very
tight. When the locking ring is fully engaged
over the threaded connector, the locking ring
may not cover all of the threads.
●
7 Tighten both locking collars.
●
8 Secure the cable with the 2 velcro straps
provided, one on the lower stem close to the
searchcoil, and one on the upper stem, close
to the housing. Leave just enough slack in the
cable, at the searchcoil end, to be able to
rotate the searchcoil a small amount about the
bolt. After full assembly and upon first use in
the field, check this adjustment. It is very
important to keep the cable secure against the
stem, especially at high Gain, as movement in
the cable may cause false signals.
Loc
kin
g
Col
lar
Loc
kin
g
Col
lar
S-R
od
Vel
cro
Str
ap
Vel
cro
Str
ap
Knurled
Kno
b
Bolt
Single
Rubber
Was
her
Sea
rch
coi
l
Hand-grip
Sea
rch
Coi
l Cable
Low
er
Stem
Middle
Stem
Cable
Plug
6
ASSEMBLY
Adjusting the Arm Rest
The Arm Rest may be moved
forward or backward by removing
the single screw and nut, and then
repositioning the 2-piece Arm Rest.
Users with shorter arms may find
the Arm Rest more comfortable in
the forward position. In order to
move the Arm Rest backward, the
plastic plug must be removed from
the aluminum tube.
Arm Rest Strap
(optional accessory)
The Arm Rest Strap accessory can
be purchased separately. Some
users prefer to use the strap when
swinging the detector vigorously, in
order to hold the detector securely
against the arm.
The detector can always be used
without the strap, with no
compromise to detector balance
and stability under most conditions.
Hand-grip
Nut
Screw
Search
Coil
Cable
Cable
Plug
Sea
rch
oil
S-Rod
armrest
Velcro
Strap
Middle
Stem
Velcro
Strap
Locking
Collar
Locking
Collar
Headphone Jacks
Single
Rubber
Was
her
Optional Arm Strap
line of defense against electrical interference. The Threshold control only applies to
the All-Metal mode.
Electrical interference is usually more controllable in the All-Metals mode than in the
Discrimination mode.
On the Gold Bug, setting the discrimination level between 60 and 70 will usually reduce
electrical interference. In the Discrimination mode, the detector may chatter if the
searchcoil is not in motion, but once you start sweeping it over the ground, the signal
from the ground will usually suppress the electrical interference chatter, except for an
occasional pop or click which will not sound like a real target.
If you are conducting an indoor demonstration, you may find that changing the
orientation of the searchcoil will reduce the pickup of electrical interference.
If you carry a cell phone or other high-tech electronic equipment while metal detecting
and you encounter electrical interference, try turning the device off and see if that solves
the problem. Turn such devices completely off, not just into standby mode.
When working near overhead power lines, you may get the best results right under the
power line and the worst results when standing at a 30° to 45° angle to the power line.
Many sources of electrical interference are intermittent. You may find that an area which
is difficult to search at one time of day may be easier after 5 PM, or on weekends.
Power lines are usually quietest late at night, and early on weekend mornings.
Small searchcoils usually pick up less electrical interference than larger searchcoils. On
a site with severe electrical interference, a small searchcoil is often a better choice than
a large one.
Distinguishing electrical interference from other problems
Electrical interference will often vary as you walk around from place to place, and it will
also vary with changes in the orientation of the searchcoil. This is almost never the
case if there is a functional problem with the metal detector itself.
The most common cause of a noisy metal detector, where the problem is not electrical
interference, is a defective searchcoil. If striking the searchcoil with your hand causes
the noise to start or stop, the problem could be a defective searchcoil. Also, a defective
searchcoil often causes noise of a more intermittent nature than electrical interference.
The second most common cause is a loose searchcoil connector. The noise from a
loose connector will usually be very erratic or intermittent in nature. Try unplugging the
searchcoil and then reconnecting it to ensure the connector is firmly installed.
If you use a searchcoil cover, dirt or water can accumulate inside it, and movement of
those materials can cause false signals while sweeping the searchcoil. Searchcoil
covers must be periodically removed and cleaned.
ELECTRICAL INTERFERENCE
7
A 3-segment battery indicator at the bottom of the display indicates the
battery condition.
The detector requires a single 9-volt ALKALINE battery.
Do not use ordinary zinc carbon batteries.
Do not use “Heavy Duty” batteries.
Rechargeable batteries can also be used.
If you wish to use rechargeable batteries, we recommend using a
Nickel Metal Hydride rechargeable battery.
The battery compartment is located on the back side of the housing.
Slide the battery door to the side and remove it to expose the battery
compartment.
BATTERY LIFE
Expect about 15 to 20 hours of life from a 9-volt alkaline battery.
Rechargeable batteries can provide up to 8 hours of usage per charge.
SPEAKER VOLUME AND BATTERY CHARGE
You may notice the speaker volume drop when only one battery segment is
illuminated.
With one segment flashing, low speaker volume will be very apparent.
BATTERY INDICATOR
The 3-segment battery indicator has 3 stages of indication.
These indications are accurate for a 9-volt alkaline battery.
Segments Illuminated Battery Voltage
3 -segments more than 8.5 volts
2 -segments more than 7.5 volts
1 -segment flashing more than 6.8 volts
After the 1st segment begins flashing, expect the detector to shut off within 10
minutes.
A rechargeable battery will usually illuminate two to three segments
throughout most of its useful charge. But as soon as it drains to the 1-segment
level, it will then lose its charge very rapidly.
BATTERIES
8
QUICK-START DEMONSTRATION
HOT ROCKS
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 a LOW tone.
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
A hot rock is a rock which causes the metal detector to sound off because the
rock contains iron minerals. They come in two basic types.
Negative hot rocks (also called cold rocks) are usually magnetite or
contain magnetite, and give a negative response because their ground
balance value is a higher number than the soil they are found in. They
tend to be dark in color, usually black, and usually heavy. In some cases
they will have rust stains. They are usually attracted to a magnet, and for
this reason gold prospectors always carry a magnet -- the ultimate
ferrous/nonferrous discriminator. In All Metal mode, negative hot rocks
produce a
recognize the difference and you will learn to ignore them. As the
searchcoil passes over a hot rock, this
is quite distinctive. To hear this response, you must be properly Ground
Balanced and in All-Metal mode with an audible threshold hum. First, as
the center of the searchcoil passes over the negative hot rock, the
detector will go quite; the threshold hum momentarily silences. Then,
passing beyond the negative hot rock, you hear the
pass the searchcoil back and forth over a negative hot rock, it will be
impossible to pinpioint and will seem as if it
Positive hot rocks are iron-bearing rocks which have been oxidized by
natural weathering processes so that their GRND BAL value is a number
lower than the soil they are found in. They are often small, right on the
surface, sound just like a gold nugget, and are common in many gold
prospecting areas. They are usually, but not always, drawn to a magnet.
They are most often reddish in color but are often black, brown, or yellow.
On relic hunting sites, red clay bricks and rocks which have lined a fireplace
or a campfire will often be
them without difficulty if widely scattered, but if there is a large concentration
of them, the discriminator may not quiet them all. In that case, you can
revert to the rule of thumb -- “don’t dig non-repeatable signals.”
Remember to always carry a magnet to help discriminate gold from hot rocks
and iron.
• Gold will not
• Pieces of iron will always
• Negative hot rocks will almost always
• Positive hot rocks will usually
9
X. Click the MODE knob to the right.
The detector is now in the ALL-METAL Mode
QUICK-START
continued
a. Keep GAIN set at the 12:00 position
b. Rotate the THRESHOLD knob slowly from the far counterclockwise
position to the full clockwise position.
Notice these attributes of the THRESHOLD control, with no metal
over the searchcoil.
i. at low settings you will hear no sound
ii. at mid-scale, there will be a transition point from no sound to
a barely audible, choppy sound.
iii. at full scale you will hear a loud, constant tone. It may also have
an irregular or choppy sound, as a result of electromagnetic
interference emitted from other electrical devices.
Use with headphones
(not included)
The Gold Bug Pro is equipped with both a 1/8” and 1/4” headphone jack. Any
headphones with a stereo plug will work; headphones with a mono plug will not
work. Using headphones extends battery life, and also prevents the sounds from
annoying bystanders. It also allows you to hear subtle changes in the sound more
clearly, particularly if searching in a noisy location. Gold nuggets are often very
small, so closely monitoring changes in sound using headphones will improve your
gold prospecting results. For safety reasons, do not use headphones near traffic
or where other dangers, like rattle snakes, are present. This device is to be used
with interconnecting cables/headphone cables shorter than three meters.
IX. Press-and-hold and hold the nickel over the searchcoil
a. Notice that motion is not required.
A motionless object induces a hum.
b. Notice the single monotone hum. The PINPOINT mode produces
only this single sound, regardless of the type of metal detected.
c. Move the nickel closer to and farther away from the searchcoil.
Notice the changing “depth” values.
10
THE BASICS OF METAL DETECTING
GOLD PROSPECTING
A hobby metal detector is intended for locating buried metal objects. When
searching for metals, underground or on the surface, you have the following
challenges and objectives:
1. Ignoring signals caused by ground minerals.
2.
Ignoring signals caused by metal objects that you do not want to find,
like pull-tabs.
3. Identifying a buried metal object before you dig it up.
4. Estimating the size and depth of objects to facilitate digging them up.
5. Eliminating the effects of electromagnetic interference from other
electronic devices.
Your Gold Bug Pro metal detector is designed with these things in mind.
1. Ground Minerals
All soils contain minerals. Signals from ground minerals can interfere with
the signals from metal objects you want to find. All soils differ, and can
differ greatly, in the type and amount of ground minerals present. You
therefore want to calibrate the detector to the specific ground conditions
where you are hunting. The detector incorporates both automated and
manual ground balancing features which will eliminate false signals from
most types of soils. To maximize the detector’s target identification
accuracy and depth of detection, use the GROUND GRAB (GG) function
to calibrate the detector to the ground where you are searching. See the
section on GROUND BALANCING for details.
The Basics continued on next page
practice, bits of rusted barbed wire, chips off shovels and other mining tools,
rusted tin cans, etc. Hot rocks -- rocks containing concentrations of iron
oxides that sound like metal when you pass over them -- are also a nuisance
in many gold areas. Discrimination is usually ineffective because the loss of
sensitivity resulting from discrimination is enough to cause those little nuggets
to vanish. If you have gone many hours without finding gold and are
wondering if there is something wrong with your metal detector or how you are
using it, the most important clue is this: if you are digging
metal, then if gold were present you would have found small gold pieces too!
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2. Trash
If searching for coins, you want to ignore items like aluminum foil, nails and
pull-tabs. These undesirable items are generally identified toward the lower
end of the 0-100 scale. You can listen to the sounds of all objects detected,
and decide on what you want to dig up. Or you can eliminate unwanted
metals from detection by using the DISCRIMINATION feature.
3. Identifying Buried Objects
Different types of metals are classified along the arc at the top of the screen
on a 0-100 scale from left to right. A 2-digit numerical reading is also
provided in the middle of the display for more precise target identification in
Discrimination mode.
4. Size and Depth of Buried Objects
When using the detector in the motion DISC mode, the relative depth of an
object is displayed to the left of the display over the SIGNAL strength
indicator. A more accurate depth reading is available using PINPOINT.
Pinpoint displays target depth in inches. The Pinpoint mode does not
require the searchcoil to be in motion to detect metals. The ability to hold
the searchcoil motionless over the target also aids in tracing an outline of
the buried object, or in pinpointing the exact location of the object using
techniques described in the pinpointing section of this manual.
5. Electromagnetic Interference (EMI)
Electrical 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. Common sources of electrical interference
include power lines, electronic communication equipment such as
cellphones, fluorescent lamps, military electronics such as radar, other
metal detectors and computer equipment.
Your first line of defense against EMI is to reduce the
Gain and/or
Threshold. In areas with heavy EMI, operating at reduced sensitivity levels
will result in the loss of some depth, but at least the metal detector will be
usable
See the 2-page section on ELECTRICAL INTERFERENCE for a more
thorough explanation of EMI and how to manage it
.
THE BASICS
continued
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