Fisher labs F4 User manual

OPERATING

MANUAL

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The F4 metal detector is warranted against defects in materials and

workmanship under normal use for five years from the date of purchase

to the original owner.

Damage due to neglect, accidental damage or misuse of this product is

not covered under this warranty. Decisions regarding abuse or misuse of

the detector are made solely at the discretion of the manufacturer.

Proof of Purchase is required make a claim under this warranty.

Liability under this Warranty is limited to replacing or repairing, at our

option, the metal detector returned, shipping cost prepaid to Fisher Labs.

Shipping cost to Fisher Labs is the responsibility of the consumer.

To return your detector for service, please first contact Fisher Labs for a

Return Authorization (RA) Number. Reference the RA number on your

package and return the detector within 15 days of calling to:

Fisher Labs

1465-H Henry Brennan Dr.

El Paso, TX 79936

Phone: 915-225-0333 ext.118

Warranty coverage does not include the cost of transporting the

detector back to an owner who is located outside of the United States of

America.

1465-H Henry Brennan, El Paso, TX 79936 • (915) 225-0333

Fisher®is a registered trademark of Fisher Research Labs

www.fisherlab.com

Use ALKALINE

Batteries ONLY

F4manual-SPREADS(20pg).qx 5/30/07 4:44 PM Page 1

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TABLE OF CONTENTS

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1

9

TARGET PINPOINTING

(no-motion PINPOINT mode)

After you have identified a target using a motion mode of detection,

press the PINPOINT pad 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 excavation.

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:

1

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Position the searchcoil just barely off the ground, and to the side of

the target.

2

.

Press PINPOINT pad and raise the searchcoil about 2 inches. Lifting

the searchcoil away from the ground makes the ground signal go

negative, so the machine is silent.

3

.

Now move the searchcoil slowly across the target, and you can

locate it by the sound. The target is located directly under where

the sound is loudest.

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:

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

.

Press PINPOINT pad again.

3

.

Repeat this narrowing procedure to narrow the

field of detection further.

N

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Depth indication is less accurate after

narrowing.

COIL 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; press PINPOINT to retune.

Temperature change will cause the

coil to drift in point mode.

If the detector moves from a

cooler to a warmer

environment, the detector

may emit a constant tone

until the temperature

stabilizes; if so, retune.

If the detector moves

from a warmer to a

cooler environment,

the detector may lose

sensitivity (remaining

quiet); if so, retune.

F4manual-SPREADS(20pg).qx 5/30/07 4:44 PM Page 2

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SETTING UP

No tools required.

l

1

Insert the lower stem (plastic tube) into the middle

stem.

l

2

Position the lower stem with the silver

button toward the back.

Using the bolt and wing nut,

attach the search coil to the

lower stem.

l

3

Press the button on

the upper stem,

and slide the

lower stem

assembly into the

upper stem.

Adjust the stem to

a length that lets you maintain a comfortable upright posture, with

your arm relaxed at your side, and the search coil parallel to the

ground in front of you.

l

4

Wind the cable securely around the stem.

l

5

Insert the plug into the matching connector on the right underside of

the detector body. Be sure that the key-way and pins line up correctly.

l

6

After the stem length is adjusted to your height, tighten the two

locking collars to stabilize the stems.

Arm Rest Adjustment

If you wish to change the position

of the arm rest, remove the screw

and move the arm rest to one of

the alternate hole locations.

Caution: Do not force the plug in.

Excess force will cause

damage.

To disconnect the cable,

pull on the plug.

Do not pull on the cable.

Biaxial Searchoil

Wing nut

1

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SEARCH TECHNIQUES

(in DISC mode)

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After detecting a target, do the

following:

1

.

Walk around the target in a

circle.

2

.

While circling the target,

continue sweeping the

searchcoil across the target.

3

.

Sweep once every 30° or 40° of

the circle.

If the tone does not change

and the target ID value is

consistent as you circle the

target, you can be highly

confident of the target’s

identification.

If the tone or target ID

changes as you circle the

target, you may have multiple

targets or an irregularly shaped

object.

If the tone completely

disappears at different angles,

the target may be trash or a

low-value metal.

If you are new to the hobby, dig all targets. With practice in the

field, you will soon identify audible and visual target feedback with

certain types of metal objects.

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:

1

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Sweep over target in narrowing side-to-side pattern

2

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Take visual note of spot on ground where “beep” occurs.

3

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Step 90° to the side of the target

4

.

Sweep coil over same area, at 90° to 1st sweep pattern.

5

.

This pinpoints the target location with an “X”

COIL MOVEMENT

When swinging the coil, be

careful to keep it level with

the ground about 1/2 inch

from the surface. Never swing

the coil like a pendulum.

WRONG

CORRECT

F4manual-SPREADS(20pg).qx 5/30/07 4:44 PM Page 3

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F

4

.

The batteries have

been inserted

backwards in the

compartment for

storage during

transportation.

Please remove

batteries, turn them

around, and install

correctly.

Use A

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batteries only.

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To install the batteries:

l

1

Remove the battery cover by disengaging the clip at the back.

Do not hinge door upward; pull straight back

l

2

Align the polarity of the batteries correctly, with the positive "+"

toward the coil plug connection, as indicated by the + and –

indicators on the housing.

l

3

Insert (2) 9-Volt A

A

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batteries, with the contacts pointed inward,

and press down on the back of the batteries to snap them into place.

Some brands of batteries will require moderate force to clear the

retaining tabs.

l

4

Replace the battery door.

Most metal detector problems are due to improperly installed

batteries, or the use of non-alkaline or discharged batteries. I

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BATTERIES

1

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ELECTROMAGNETIC INTERFERENCE

Use the Sensitivity Control is to eliminate

Electromagnetic Interference (EMI).

The F4 metal detector is an extremely sensitive

device; the search coil creates its own

magnetic field and acts like an antenna. If

your detector beeps erratically when the

search coil is motionless, the unit is probably

detecting another electromagnetic field.

Common sources of EMI are electric power lines, both suspended and buried,

motors, and household appliances like computers and microwave ovens.

Some indoor electronic devices, such as dimmer switches used on household

lighting, produce severe EMI and can cause the detector to beep erratically.

Other metal detectors also produce their own electromagnetic fields; so if

detecting with a friend, keep two metal detectors at least 20 feet apart.

If the detector beeps erratically, R

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by pressing the

S

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Pad on the left of the control panel.

In most urban environments, you should be able to search without chatter from

interference at the default sensitivity setting (default setting is the sensitivity level

at power-up, 4 bars), or at one level reduced from default. At maximum

sensitivity, the F4 will “chatter” in proximity to underground or overhead power

lines, or to indoor or outdoor electrical devices. In fact, if you notice rapid

chatter with the searchcoil near the ground, you may be able to trace the

approximate location of the underground power lines by following the chatter.

To manage chatter, which is most likely from electrical interference:

1

.

R

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t

h

e

S

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S

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V

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Y

until the chatter stops.

2

.

Try sweeping it over the ground.

If the F4 chatters while held still, or held up in the air, it may be much

quieter when sweeping over the ground.

3

.

Operate in AUTOTUNE mode

Interference is much more tolerable in this mode, even at high sensitivity.

SEVERE GROUND CONDITIONS

A secondary use for the Sensitivity Control is to reduce false detection signals

caused by severe ground conditions. While the detector contains circuitry to

eliminate the signals caused by most naturally occurring ground minerals, 100%

of all ground conditions cannot be anticipated. Highly magnetic soils found in

mountainous and gold-prospecting locations can cause the detector to emit

tones when metal objects are not present. High saline content soils and sands

can sometimes cause the detector to beep when no metal target is present.

If the detector emits false, non-repeatable, signals, REDUCE THE SENSITIVITY.

SENSITIVITY ADJUSTMENT

HEADPHONE JACK

Using headphones (not supplied)

with your metal detector makes it

easier to identify subtle changes in

the threshold levels for better

detection results, and also reduces

drain on the batteries. Any stereo

headphone with 1/4” jack will work.

F4manual-SPREADS(20pg).qx 5/30/07 4:44 PM Page 4

QUICK-START DEMONSTRATION

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• A Nail • A Quarter

•

A Pull-Tab from a beverage can • A Zinc Penny (dated after 1982)

• A Nickel

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a. Place the detector on a

table, with the search

coil hanging over the

edge. (or better, have a

friend hold the detector,

with the coil off the

ground).

b. Keep the searchcoil

away from walls, floors,

and metal objects.

c. Remove watches, rings and other jewelry or metal objects from

hands and wrists.

d. Turn off appliances or lights that cause electromagnetic

interference.

e. Pivot the search coil back

toward the detector body.

I

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Press the ON/OFF touch pad.

I

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a.Notice a different tone for

each object.

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:

Nail

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T

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:

Pull-Tab

M

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T

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:

Zinc Penny

H

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T

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:

Quarter

b.Motion is required. Objects

must be in motion over the

search coil to be detected.

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The detector will beep and

2 “R”’s will appear under

the iron indicators.

Quick-Start Demo continued

on next page

5

1

6

DD COIL CHARACTERISTICS

A DD coil is superior to a concentric coil, but sometimes requires a

different sweep technique.

Advantages are

1

.

Better target separation

2

.

Superior performance in highly mineralized ground

3

.

Broader Sweep- cover more ground with each sweep

If you experience multiple responses on a shallow target, you can

raise the coil, or narrow the sweep over known targets to only

intersect the center section of the coil.

BOTTLE CAPS

The disadvantage of the DD coil is its propensity to

classify steel bottle caps as coins.

If you hear a high tone in DISC mode and believe

that it is a coin, make sure it is not a bottle cap using

the following method.

1

.

If a repeatable ID# around 68 to 72, then it

should be a dime or copper penny.

2

.

If not in the range of 68 to 72, then:

a

.

Sweep the back end of search coil over

the target. If tone changes from high to a

low tone, it is probably a bottle cap.

b

.

Sweep search coil fast across target.

1

.

If tone and ID-value

drop, it is probably a

bottle cap.

2

.

If a bottle cap, the

faster you sweep, the

lower the tone.

The F4 is supplied with a standard

4” auxiliary search coil. The 4” coil

will not classify steel bottle caps in the 10¢ and

higher coin categories and they can be easily

discriminated out.

SWEET SPOT

The “center” of the DD-Coil is elongated (elliptical) from top to

bottom of the coil. With some practice you will find where the center

of this ellipse lies on your coil. Use this center point as a reference in

pinpointing.

Sweep back end

of searchcoil over

suspected bottle cap.

(Low Tone = Bottle Cap)

F4manual-SPREADS(20pg).qx 5/30/07 4:44 PM Page 5

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V

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a. The Nail will not be detected.

b. The Nail has been "Discriminated Out."

V

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“

D

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+

”

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3

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.

Five “R”s are now

displayed.

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The Nail and Pull-Tab will

not be detected.

The other objects will be

detected with their own distinctive tones.

I

X

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N

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C

H

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.

A flashing “▲” will

appear under the IRON-1

segment.

X

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D

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+

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.

The flashing “▲” will move

to the 5¢ segment.

X

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The “R” will disappear under

5¢ segment.

X

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The nickel is detected.

X

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.

The arrow under the 1¢ segment will flash & then the “R” will illuminate.

X

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.

The penny (the most recently detected item) is eliminated from

detection.

X

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.

Hold one of the metal objects motionless over the search coil.

• All Metal objects are now detected.

•

One monotone sound indicates the presence of any type of metal.

•

A 2-digit numerical display indicates approximate target depth, in inches.

QUICK-START DEMONSTRATION

(continued)

1

5

DEPTH AND TARGET DISPLAY

C

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/

1

0

¢

:

Dimes and pre-1982 pennies will

register here. Older, pre-1982, pennies

are composed of copper, which has a

metallic signature similar to a dime. Most

copper coins will register here.

C

a

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i

o

n

:

The target indications are

visual references. Many other types of

metal can fall under any one of these

categories. While the F4 will eliminate

or indicate the presence of most

common trash items, it is impossible to

accurately classify ALL buried objects.

DEPTH INDICATOR:

The Depth Indicator is calibrated to

coin-sized objects. It indicates the

depth of the target, in inches. Large

and irregularly-shaped objects will

yield less reliable depth readings

When passing over an object, the depth

indicator will light up and stay

illuminated until another object is

scanned. Repeated indication at the

same depth level indicates an accurate

target detector. If the depth indication

varies with each sweep, try sweeping at

different angles; there may be more

than one target present. With practice,

you will learn the difference between

accurate readings, multiple targets, and

highly erratic readings which evidence

trash or irregularly shaped objects.

2-DIGIT DEPTH In Pinpoint Mode

In PINPOINT mode, the 2-digit number

indicates estimated target depth in

inches. The read-out is calibrated to,

and is most accurate for, coin-sized

objects. Larger and smaller objects

will produce a relative depth reading.

The 2-digit number will be most accurate

when the detector is accurately ground-

balanced, and when the threshold is set

for no audible threshold sound (or for a

very faint background hum).

The depth indicator will be less

accurate if you have “de-sensitized”

the detector over a metal target, as is

the practice when “narrowing it down”

in the pinpointing process. The depth

indicator will also be inaccurate if you

operate in PINPOINT mode with an

audible tone above a slight threshold

background hum. Such inaccuracy will

be less apparent when the object to

closer to the searchcoil, but more

apparent when farther away.

2 DIGIT TARGET INDICATOR

In disc or notch mode, the 2-digit target

indicator, in the middle of the LCD

display, provides a specific target value

to help identify buried targets more

accurately. With practice in the field, you

will learn to associate target values with

the probable identification of buried

objects. The target value can vary each

time the coil passes over the target,

depending upon the angle of the object

and the distance from the coil.

A

s

a

s

t

a

r

t

i

n

g

p

o

i

n

t

,

r

e

f

e

r

t

o

t

h

e

t

a

b

l

e

b

e

l

o

w

.

T

A

R

G

E

T

R

e

a

d

o

u

t

The table below lists some common

approximate target value

equivalents. With experience in the

field, you will recognize many types

of metals by their numeric value.

T

Y

P

I

C

A

L

P

O

S

I

B

L

E

V

A

L

U

E

O

B

J

E

C

T

S

0-15 Iron

25-28 Pull-Tab Tail (broken off)

28-32 Nickel

36-42 Pull-Tab (old type)

58-62 Zinc, Penny

68-72 Dime & Wheat Cent

78-83 Quarter

86-90 Half Dollar

91-95 Silver Dollar

F4manual-SPREADS(20pg).qx 5/30/07 4:44 PM Page 6

7

T

h

e

o

p

e

r

a

t

i

n

g

c

o

n

t

r

o

l

s

a

r

e

a

s

f

o

l

o

w

s

:

SENSITIVITY + AND –

These controls change the detector’s sensitivity;

higher settings enable detection of deeper

targets. At power-up, the detector is pre-set to

75% of maximum sensitivity. At minimum, the

sensitivity is 35% of maximum. With each press of

the + or – touch pads, the sensitivity level is

displayed on the bar graph on the left of the

display. Upon reaching the minimum or maximum

sensitivity setting, the detector will beep twice.

While higher levels of sensitivity enable detection of deeper targets,

operation at high levels of sensitivity make the detector m

m

o

r

e

s

u

s

c

e

p

t

i

b

l

e

t

o

e

l

e

c

t

r

o

m

a

g

n

e

t

i

c

i

n

t

e

r

f

e

r

e

n

c

e

.

Higher sensitivity settings can also lead

to false signals in difficult ground conditions. Use lower sensitivity settings

to suppress interference or false signals from soil minerals when necessary.

I

f

t

h

e

d

e

t

e

c

t

o

r

“

C

h

a

t

e

r

s

”

,

r

e

d

u

c

e

s

e

n

s

i

t

i

v

i

t

y

.

AUTO TUNE (All Metal)

P

r

e

s

t

h

i

s

p

a

d

a

n

d

“

A

L

M

E

T

A

L

”

a

p

e

a

r

s

o

n

t

h

e

d

i

s

p

l

a

y

This mode is a ground-balanced all-metals

motion search mode. This mode offers the

maximum amount of sensitivity under most

ground conditions. The search coil must be in

motion to detect metal. One monotone sound

is emitted. No discrimination or target

identification is possible in this mode.

Use the S

S

e

n

s

i

t

i

v

i

t

y

or T

T

h

r

e

s

h

o

l

d

controls to change the sensitivity or

background hum. Maximum sensitivity to buried metal objects is

achieved with a slightly audible background hum.

T

o

a

c

h

i

e

v

e

a

n

a

u

d

i

b

l

e

b

a

c

k

g

r

o

u

n

d

h

u

m

:

1

.

Press AUTO TUNE pad to enter this mode.

2

.

Press S

S

e

n

s

i

t

i

v

i

t

y

+

or -

-

pads until you reach a desired setting.

This sensitivity setting may be the highest “quiet” setting, or you may

hear a faint background hum.

3

.

Press T

T

h

r

e

s

h

o

l

d

+

o

r

-

pad until you reach a comfortable volume level.

The Sensitivity control works like a course adjustment in this mode.

The Threshold control works like a fine adjustment in this mode.

The AUTO TUNE mode must be ground-balanced to eliminate interfering

signals from soil minerals. See the section on ground balancing for a

description of this procedure.

CONTROL PANEL

1

4

DEPTH AND TARGET DISPLAY

READING THE DISPLAY

The Liquid Crystal Display (LCD) shows

the PROBABLE identification of the

targeted metal, as well as the PROBABLE

depth of the target, in inches.

An arrow will illuminate under the

target category where an object is

best classified, and stay illuminated

until another target is identified.

The detector will normally register a

repeating, unchanging target

identification when a buried target

has been located and identified. If,

upon repeated passes over the same

spot, the target identification reads

inconsistently, the target is probably a

trash item, oxidized metal, or too

deep to be classified accurately. With

practice, you will learn to unearth

only the more repeatable signals.

The segment identifications are highly

accurate, when detecting the objects

described on the label. However, if

you register in a given category for an

unknown buried object, you could be

detecting a metallic object other than

the object described on the label, but

with the same metallic signature. Also,

the greater the distance between the

target and the coil, the less accurate

the target identification.

G

O

L

D

T

A

R

G

E

T

S

Gold objects will

register on the left side of the LCD scale.

Gold will register depending upon its

size. The smaller the gold object, the

further to the left it will register.

G

o

l

d

f

l

a

k

e

s

will register under Iron-1

S

m

a

l

g

o

l

d

i

t

e

m

s

will register under

Iron or 5¢/PT.

M

e

d

i

u

m

-

s

i

z

e

d

g

o

l

d

i

t

e

m

s

will

register under PT or S-cap.

L

a

r

g

e

g

o

l

d

i

t

e

m

s

will register under

S-cap or Zinc.

S

I

L

V

E

R

T

A

R

G

E

T

S

:

Silver objects will

normally register to the right of the

scale, under 10¢, 25¢, 50¢, or $1,

depending on the size of the object.

The larger the object, the farther to

the right it will register.

I

R

O

N

:

Ferrous objects will register on

the far-left side of the target

identification scale. 1, or 2 indicates

the relative size of iron objects. Small

nails, for instance, will usually

illuminate the Iron-1 arrow whereas

large structural ferrous objects will

usually illuminate the Iron-2 arrow.

Objects in this category could be

worthless scrap, or a more valuable

iron relic.

5

¢

/

P

T

:

Nickels and most newer pull-

tabs(those that stay attached to the

can) will register here.

P

T

(

p

u

l

-

t

a

b

s

)

:

Pull-tabs from older

beverage cans will register here. Few

newer pull-tabs will also register here.

Many gold rings will also register here.

S

C

(

S

c

r

e

w

C

a

p

s

)

:

Screw caps from

glass bottles will register here. Large

gold rings, like a class ring, could also

register here. Some non-U.S. coins will

also register here.

Z

I

N

C

/

1

¢

:

Newer pennies (post-1982)

will register here. Many non-U.S. coins

of recent vintage will also register

here.

F4manual-SPREADS(20pg).qx 5/30/07 4:44 PM Page 7

DISCRIMINATION (THRESHOLD) + AND –

The f

f

u

n

c

t

i

o

n

o

f

t

h

i

s

c

o

n

t

r

o

l

d

e

p

e

n

d

s

u

p

o

n

t

h

e

o

p

e

r

a

t

i

n

g

m

o

d

e

you are in before you press

these touch pads.

AUTO TUNE

+

a

n

d

–

will change the threshold sensitivity

of the detector in this mode. This T

T

h

r

e

s

h

o

l

d

control operates like a fine adjustment for

setting the sensitivity level and the volume

of the background audible hum. If you

continue to press +, you will cause the

detector to make a sound, or hum, when

no metal is present. Depending upon skill

level and environment, some users prefer to operate in AUTO TUNE

with an audible hum active at all times. At such a high “threshold,”

faint signals from deeply buried or very small objects will be more

apparent to the user.

PINPOINT

Not applicable.

The +

+

a

n

d

–

touch pads have no function in this mode.

DISC

+

a

n

d

–

will increase or decrease the level of

discrimination. Each press of the pads will

cause an “R” to appear or disappear on the

display. When the “R” appears, the

corresponding target category will be

eliminated from detection. No audible tone

nor target-arrow will appear when the

searchcoil passes by an object in a

category with an “R” illuminated. A

maximum of seven “R”s can be displayed, eliminating objects up to

the Zinc-1¢ category. The four right-most target categories cannot

be eliminated from detection.

NOTCH

When Notching-Out a target, the +

+

a

n

d

–

pads will move a flashing

arrow to the target category selected for

notching. This feature allows you to

discriminate items selectively across the

target spectrum. While the “discrimination”

control eliminates all targets from left to right,

this control allows you to either add back

categories previously eliminated (changing

from “R” to “blank”) or to selectively eliminate

categories (changing from “blank” to “R”).

8

CONTROL PANEL

1

3

4-TONE AUDIO SYSTEM

While the LCD (Liquid Crystal Display) is very accurate in identifying

buried objects, the user in the field does not always maintain the

display screen in his field of vision. Therefore, we have incorporated an

audio feedback mechanism to alert the user to the nature of buried

objects. This audio feedback system first alerts the user to the presence

and classification of objects, whose nature and location can be

confirmed using the LCD display.

The 4-tone audio target identification system functions only in the motion

modes of operation. The detector must be in the DISCRIMINATION

mode, as indicated on the display. In PINPOINT or AUTOTUNE modes, the

detector will emit only a monotone sound.

The detector can sound four different tones, depending on the object

detected.

L

O

W

T

O

N

E

Ferrous objects, such as iron and steel, will induce a low tone.

The smallest gold objects can also induce a low tone.

L

O

W

-

M

I

D

Pull-Tabs, nickels & smaller gold

M

E

D

I

U

M

T

O

N

E

Newer pennies (post-1982), larger gold objects, zinc, and small

brass objects, will induce medium tones. Many recent vintage

non-U.S. currencies will induce medium tones.

H

I

G

H

T

O

N

E

Silver and copper coins, larger brass objects and older pennies

(pre-1982), will induce high tones. Quarters, dimes and other

precious coins fall into this category.

Audio Target Identification (ATI) classifies metals into four categories.

L

O

W

T

O

N

E

Nails, Iron Objects,

& Smallest Gold Objects

L

O

W

-

M

I

D

T

O

N

E

Pull Tabs, Nickels,

& Smaller Gold

M

E

D

I

U

M

T

O

N

E

Zinc Pennies (Post 1982),

Larger Gold Objects

H

I

G

H

T

O

N

E

Copper, Silver & Brass

Copper Pennies (Pre 1982)

F4manual-SPREADS(20pg).qx 5/30/07 4:44 PM Page 8

PINPOINT

This is a static search and static pinpointing

mode; no coil motion over the target is required

to detect metal. This mode is most effective in

pinpointing the exact location of small buried

objects. The detection sensitivity of this mode is

controlled by the S

S

E

N

S

I

T

I

V

I

T

Y

+

o

r

–

touch pads.

D

i

s

c

r

i

m

i

n

a

t

i

o

n

(t

t

h

r

e

s

h

o

l

d

)

+

/

-

has no function.

Reduced sensitivity, and thus a smaller search

field, can also be achieved by pressing the

P

I

N

P

O

I

N

T

pad while an object is in the coil’s

detection field. The greatest sensitivity to large,

deeply-buried objects is achieved with this mode.

I

f

y

o

u

p

l

a

n

t

o

u

s

e

P

I

N

P

O

I

N

T

a

s

a

c

o

n

t

i

n

u

o

u

s

e

a

r

c

h

m

o

d

e

,

t

h

e

d

e

t

e

c

t

o

r

m

u

s

t

b

e

g

r

o

u

n

d

-

b

a

l

a

n

c

e

d

b

e

f

o

r

e

s

e

a

r

c

h

i

n

g

.

DISC

This control invokes motion target identification

search modes.

Successive presses of the DISC pad will toggle

back and forth between the:

1. All-Metal Discrimination mode: a motion

mode where all metal targets are detected

and the:

2. Discrimination mode: a motion mode where

the user can selectively eliminate target

categories from detection.

When the detector powers up, it automatically enters ALL-METAL

DISCRIMINATION mode with no targets eliminated from detection.

Press DISC to enter discrimination mode.

In order t

t

o

e

l

i

m

i

n

a

t

e

m

o

r

e

t

a

r

g

e

t

s

from detection, press the

D

I

S

C

R

I

M

I

N

A

T

I

O

N

+

pad.

To reverse this target elimination, press the

D

I

S

C

R

I

M

I

N

A

T

I

O

N

–

pad; illuminated “R”s will disappear.

9

CONTROL PANEL

1

2

7

.

Notice that the position of the KNOB affects

the sound relative to the coil’s direction:

a

.

If you hear a louder sound as the

searchcoil is lowered toward the ground,

we call this positive response.

b

.

If you hear a louder sound as the

searchcoil is lifted away from the ground, we

call this negative response.

8

.

Rotate the knob both clockwise and

counterclockwise while pumping

the coil and notice the KNOB

position where the sound

changes from negative

response to positive response.

9

.

Set the KNOB at the position

where you achieve a slight

positive response.

i.e. the sound is slightly

louder as the coil is

lowered toward the

ground.

C

A

U

T

I

O

N

:

cannot ground balance over a metal object.

A

l

t

e

r

n

a

t

e

Q

u

i

c

k

G

r

o

u

n

d

B

a

l

a

n

c

i

n

g

M

e

t

h

o

d

You may also use the following, simpler method, to ground balance.

While not as accurate as the coil-pumping method in AutoTune, it

yields an approximate ground balance setting.

Find a patch of ground free of metal

1

)

Set the ground-balance knob at the pre-set position, 100%

clockwise.

2

)

Position the searchcoil about 6” over the ground.

3

)

Press PINPOINT button

4

)

Lower searchcoil to within 1” of the ground. Sound will get louder.

5

)

Rotate knob slowly counterclockwise until detector is just silent.

6

)

Rotate knob back slightly clockwise until you hear a low volume

sound. At this low-volume setting, the detector is approximately

ground balanced.

GROUND BALANCING

(continued)

F4manual-SPREADS(20pg).qx 5/30/07 4:44 PM Page 9

1

0

CONTROL PANEL

As you sweep the searchcoil over a metal object, a numeric target

identification will appear in the center of the display. At the same time,

the bar graph on the left of the display will indicate the target depth, in

inches. See the scale printed on label to left of the bar graph. This

scale is calibrated to coin-sized objects. If the target is larger than a

coin, it can be used to approximate relative target depth.

NOTCH

This control allows you to selectively include or exclude target

categories from detection. The NOTCH control can be invoked from

any search mode. After selecting the categories to notch-in or notch-

out, the detector will always return to the motion discrimination mode.

Notching functions in two ways, manual or automatic.

MANUAL NOTCH

If no target arrows are visible, pressing the NOTCH pad will display

an “R” under all target categories currently eliminated and the “▲”

under Iron1 will flash.

Use the D

D

i

s

c

r

i

m

i

n

a

t

i

o

n

+ o

o

r

– pads to move the position of the

flashing “▲”. Pressing NOTCH a 2nd time will change the state of

the “R” under the flashing “▲”; if the “R” was previously illuminated,

it will disappear. Conversely, if the “R” was not illuminated, a 2nd

press of the NOTCH pad will illuminate the “R”, causing this category

to be eliminated from detection.

Practice by pressing the NOTCH pad in conjunction with the

D

i

s

c

r

i

m

i

n

a

t

i

o

n

+ a

a

n

d

–

pads; their function will

quickly become obvious.

AUTOMATIC NOTCH

If a target has just been

detected and a target

arrow is visible, pressing

NOTCH will immediately

illuminate a flashing “▲”

under this category.

Press NOTCH a 2nd time to

eliminate that target

category from detection.

This Automatic Notch

feature is a convenient way to quickly eliminate the most recently

detected target from future detection.

1

GROUND BALANCING

What is Ground Balancing?

Why do I need to Ground Balance?

All soils contain minerals. Signals from ground minerals are often tens or

hundreds of times as strong as the signal from a buried metal object.

The magnetism of iron minerals, found in nearly all soils, causes one

type of interfering signal. Dissolved mineral salts, found in some soils, are

electrically conductive, causing another type of interfering signal.

Ground Balancing is the process by which the metal detector cancels

the unwanted signals coming from the ground minerals while still

detecting the signals from buried metal objects. This is accomplished

by calibrating the detector’s phase response, eliminating the signals

from ground minerals.

When the detector is calibrated to the soil, the result will be deeper

target detection, quieter operation, and more accurate target

identification.

H

o

w

t

o

G

r

o

u

n

d

B

a

l

a

n

c

e

y

o

u

r

d

e

t

e

c

t

o

r

:

(

Preferred method

)

Find a patch of ground free of metal

1

.

Rotate the G

G

r

o

u

n

d

-

B

a

l

a

n

c

e

K

N

O

B

100% clockwise to the Preset

position.

2

.

Press the A

A

U

T

O

T

U

N

E

pad. ALL-METAL appears on the display.

3

.

Press S

S

e

n

s

i

t

i

v

i

t

y

+

pad several times to reach the highest “quiet”

setting or a setting with a

faint background hum.

4

.

Press T

T

h

r

e

s

h

o

l

d

+ o

o

r

– to

adjust the audible hum to a

comfortable level.

5

.

Physically pump the

searchcoil and detector up

and down over the ground.

Lift the searchcoil about 6

inches above the ground

and lower it to within 1 inch

of the ground, about once

or twice a second.

6

.

While pumping the

searchcoil over the ground

in this fashion, slowly rotate the KNOB counterclockwise.

F4manual-SPREADS(20pg).qx 5/30/07 4:44 PM Page 10

Fisher Labs F4 User manual

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