Page 27
T
The devic
pinpoint mode
see below
Depth detection is adjusted pr
varies accor
depth for a
pinpoint proc-
tion. -
mining the pro
IMPORT If you wan
do the follo
simultaneously and turn the device on.
need to turn the device-
izing, ''SI'' will
LARGE OR NEAR-SURF
T
suspect a target
signal is
in the sear
a siren.
search c
F
Sometimes, the
no metal tar
device.-
tent, su
or corrode
Surrounding electromag
detector is oper
search a
you ma
ground
high, please r
MA
The Magnetic
low miner
is high, the
summarized as
are w
high. If you
This measur
mineralization,-
netic mineraliza
this measureme
produced
ROCKS AND SEARCHING IN ROCKY
Challenging ground conditions arise especially when conductivity and magnetic properties
of the ground is too intense
by selecting the best operating mode and using proper ground balance
threshold settings.
Stones and rocks or cavities inside the ground are as impor
to the search and target detection qualit
Soil and rocks have two different properties just like the
of them is the
and these two proper
- magnetic permeability ratio will
low conductivity results in low ID. Soil or rocks can be
IDs as well. If the
also increase.
Hot rocks-
parison to the
The negativ
is properly
hot rocks
of rocks
balance without
P
(GEN and GEN (D)) they pr
If the signal is strong enough, the device may pr
in the General Search modes, pr
over them.
P
provide a sound in discrimination modes (except for rare cases of false signals).
At higher settings of
rocks. A
but the negative
Theref
device in the field
rock or a piec
if the det ec t ed tar get is a r ock or metal b y check ing the ID . Ho w ev er , r emember tha t w eak
sig nals ma y pr oduc e diff er en t IDs and metals under r ocks ma y pr oduc e diff er en t metal
sig nals . T her ef or e , the most appr opr ia t e ac tion is t o dig up when a metal sig nal is r ec eiv ed .
I f y ou a r e o p e r a ti n g wi t h d i s cr i m i n a t i o n mo d e s an d y o u k n o w t he I D of t h e su r r o u nd i n g
r o ck s , y o u can us e t he D is c . s e t t i ng t o e l i mi n a t e t h e r o c k s . H o w e v e r , t h is m a y n ot b e s u f f i ci e n t
t o a v oi d a ll r o ck s i g n a ls . T h e d e v i c e m a y s t i ll r e c ei v e s i g n al s f r o m r o ck s b e c au s e s o i l an d r o c k s
t o g et h e r wi ll f or m a c o m b i n e d e ff e c t a n d ge n e r a t e a d i f f e r e n t I D t h an t h o s e o f r o ck s .
NO TE: I n sta ti c modes , the devic e will pr oduc e an audio r esponse f or t he posi tiv e r oc ks bu t
not f or the nega tiv e ones . T he eff ec ts of r ocks will be r eflec t ed on scr een as dr i f ts in t he r igh t
(pos itiv e) or le f t (nega ti v e) dir ec t ion in th e I D s cale . I n th e cas e of a pos iti v e d r if t , th er e ar e 2
w a y s t o check whet her the tar g et is a r ock or not:
1) I f the ID scale fills up instan tly along with the audio and then dr ops ,
2) I f it does not pr o vide an y ID a t all or a v er y lo w ID , then the tar get is a r ock .
TR A CKING AND EFFEC T S OF ROCKS
W hen the tr ack ing is ac tiv e , the devic e ma y g iv e an audio r esponse and ID when it passes
o v er a hot r ock because the eff ec t of the r ock will be diff er en t than the g r ound's . I f y ou
swing the sear ch c oil o v er the r ock , tr ack ing will aut oma tically adjust the setting and the
audio r esponse/ID will either disappear or diminish sig nifican tly . B ecause ther e is a sligh t
dela y in tr ack ing , y ou ma y hear a str ong sig nal a t the first one or t w o swings un til the
setting is adjust ed . T hen the sound will get w eaker and disappear . T his will not happen with
metal tar gets because metals will pr ev en t the devic e fr om g r ound balancing . T her ef or e , in
tr ack ing , if y ou ar e getting a c onstan t sig nal o v er a tar get af t er r epea t ed swings , ther e is a
high possibilit y tha t the tar get is a metal . M o ving fr om o v er a r ock back t o soil , the devic e
ma y g iv e sig nals t o the g r ound f or a f ew swings un til the g r ound balanc e setting is upda t ed
again. T his is nor mal and should not mislead y ou .
T r ack ing is not r ec ommended t o elimina t e r oc ks un der nor mal c onditions . I t is r ec om -
m en d e d f o r u s e i n ar e a s w i t h c h a n g in g s o il t y p e s .
ME T ALS UNDER ROCKS
IMP A C T i n c r ea s e s t h e p o s si b i l i t y of d et e c t i ng me t a l t a r g e t s u n d e r m i n e r a li z e d r o c k s t h r o ug h
t h e p r op er ad j us t m e n t o f y o u r se t t i n g s . T h e c o m b i ne d e f f e c t c r e a t e d b y t he r ock a n d m e t al
t o g et h e r i s lo w er t h an t h e e f f e c t t ha t t h e m e t al cr ea t e s b y i ts e lf a nd t he di s p la y e d I D wi l l b e
d i f f e r e n t t h a n t h e m e ta l' s e x p e c t e d I D . T h e di s p l a y e d I D i s f o r m e d b y t he c o m b i n a t i o n o f r o c k
a n d m e t al t og e t h er a n d ge t s c los e r t o t h e I D of t h e r o c k i f th e s i z e o f t h e m e t a l i s s m a lle r i n
r e l a t i o n t o t h e r oc k . K e e p i n m i nd t h a t m e t al s u n d e r h o t r oc k s wi l l n e v e r a p p e a r w it h t h e i r
o w n m et al I D . F or i n s t a nc e , a g o ld pi e c e u n d e r a b r i c k ma y p r od uc e a n i r o n t o n e a n d I D .
R emember this v er y simple pr inciple as it will sa v e y ou lots of time: “I f the tar get y ou det ec t
is not a st one , it can be metal ” .
T he key t o det ec ting tar gets under miner aliz ed r ocks , par ticular ly when positiv e r ocks ar e in
question, is the k no wledge of the maximum ID v alue pr oduc ed b y the sur r ounding positiv e
r ocks . I f y ou ar e per f or ming a sear ch in the G ener al S ear ch modes , monit or the ID pr oduc ed
b y the devic e . I f the ID pr o vided b y y our devic e is close t o the r ock and ir on z one , it is quit e
possible tha t y ou det ec t ed a tar get under the r ock . I n the case of using Disc . in the GEN
mode , all r ocks belo w the Disc . lev el will pr oduc e a lo w ir on t one and all abo v e will pr oduc e
a higher t one .
I f y ou filt er off the r ocks with a c or r ec tly adjust ed ID Disc . setting in discr imina tion modes ,
y ou can hear the sig nal of the tar get under the r ock if the tar get sig nal has a sligh tly g r ea t er
eff ec t than the filt er ed ID . T he impor tan t thing her e is tha t if y ou det ec t a tar get and dig out
a r ock , y ou should not e the ID y ou got bef or e digg ing and use it as the Disc . v alue the ne x t
time .
F o r i n st a n c e ; t he ho t r oc k s i n y o ur se a r c h f i el d t e n d t o g i v e I Ds ar ou n d 0 0 -0 1 . I n t h i s c a se , y o u
s h o ul d s e t t h e D i s c . t o m a x i mu m 0 2. T h i s w a y y o u c an e li m i n a t e r o c k s a n d r e c e iv e t he s i g n a l s
o f m et al s u n d e r n e a t h . I f y ou s et t h e D i s c . t o o h i g h u n n e c e s s ar i l y , y o u w i l l los e m e t al s al o n g
w i t h r oc k s .
I f t h e h o t r o c k s i n y o u r s e a r c h a r e a t e n d t o g i v e h i g h I D s , t h e n t h e ch an c e s o f m i s si n g t he
s i g n a l s o f s m a ll m e t a l s u n d e r n e a t h w i l l b e h i g h a s w e l l .
SEARCHING IN SHALL O W W A TER AND BEA CH
A ll sear ch c oils of the IMP A C T metal det ec t or ar e w a t er pr oof . T his pr o vides c on v enien t
sear ching in shallo w w a t er and on the beach. W hen sear ching ar ound w a t er , be car eful not
t o get the sy st em bo x w et . T his includes the ar m cup and c on tr ol head elec tr onics .
A s e x p l ai n e d b e f o r e , s a l t w a t e r an d a l k a l i g r o u n d s a r e s i g n i f i c a n t l y c o n d u c t i v e a n d c a u s e
e f f e c t s s i m i l a r t o i r o n i n d e t e c t or s . IMP A C T ’ s C O G m o d e i s s p e c i a ll y d e s i g n e d f o r s u c h
c o n d i t i on s . Y o u c a n p e r f o r m y o u r s e a r ch e a s i l y u s i ng th e C O G m o d e wi t h o u t r e q u i r i n g an y
s p e c i a l s e t t i n g s .
C OG mode is ideal f or salt y w et beach sand . Y ou can use the other modes while per f or ming
sear ch o v er dr y be ach sand .
Y ou should c onsider the f ollo wing while per f orming sear ch o v er w et beach sand or
wate r :
1) W h e n y ou sw i n g t h e s e ar c h c oi l o v e r t he h o le s y ou d i g i n w e t be a c h s a nd , y ou ca n r ec e i v e
m e t al s i g n a ls , t h i s i s a no r m a l c on d i t i on .
2) T h e s e a r c h c o i l m a y g i v e f a l s e s i g n a l s w h e n g o i n g i n t o a n d c o m i n g o u t o f t h e w a t e r s o
p le a s e t r y t o k e e p t h e c o i l e i t h e r i n o r o u t o f t h e w a t e r .
