Schonstedt GA-92 XTd, Instruction Manual

12

Correct

Stake

Orientation

When

placing

stakes,

correct

orientation

is

important.

For

checking

purposes,

the

orientation

of

the

pin

relative

to

the

locator

is

shown

in

Figure

16.

Check

the

pin

with

one

orientation.

Then

rotate

the

pin

180°.

The

orientation

that

gives

the

largest

reading

is

the

one

that

should

be

used.

This

reading

should

be

positive

in

the

Northern

Hemisphere

and

negative

in

the

Southern

Hemisphere.

An

iron

pin

has

two

types

of

magnetization.

One

is

the

magnetization

induced

by

the

Earth's

magnetic

field.

The

induced

magnetization

is

always

downward

in

the

Northern

Magnetic

Hemisphere

and

produces

a

positive

output

no

matter

which

end

of

the

stake

is

driven

into

the

ground.

The

other

type

of

field

is

the

permanent

magnetization

that

is

fixed

to

the

pin.

For

maximum

detection,

the

stake

should

be

driven

into

the

ground

such

that

the

permanent

magnetization

is

in

the

same

direction

as

the

induced

magnetization.

Locating

Manholes,

Septic

Tanks

and

Well

Casings

The

magnetic

field

is

strongest

at

the

edge

of

a

shallow

manhole

cover.

You

can

easily

trace

the

edges

of

covers

near

the

surface.

Locating

depths

for

manhole

covers

range

up

to

8

feet.

Figure

17:

Locating

Manhole

Covers

The

great

length

of

a

well

casing

provides

a

strong

field

at

the

surface

that

makes

it

easy

to

locate

casings

buried

up

to

15

feet

deep.

Figure

18:

Locating

Water

Well

Casings

Figure

16:

Checking

a

Stake’s

Orientation