Page 26
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
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search a
you ma
ground
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MA
The Magnetic
low miner
is high, the
summarized as
are w
high. If you
T h i s m e a s u r e m e n t i s i m p o r t a n t f r o m t w o a s p e c t s . F i r s t , o n g r o u n d s w i t h h i g h m a g n e t i c
m i n e r a l i z a t i o n , s e a r c h d e p t h i s l o w a n d u s e r s s h o u l d b e a w a r e o f t h i s f a c t . S e c o n d , m a g -
n e t i c m i n e r a l i z a t i o n i s a p r o p e r t y w h i c h i s p ar t i c u l a r l y s e e n w i t h m i n e r a l i z e d r o c k s a n d
t h i s m e a s u r e m e n t p l a y s an i m p o r t a n t r o l e f o r t h e d e v i c e t o e l i m i n a t e t h e f al s e s i g n a ls
p r o d u c e d b y t h e s e r o c k s .
ROCKS AND SEARCHING IN ROCK Y TERR AINS ( GENER AL AND DISCRIMINA TION MODES)
Challeng ing g r ound c onditions ar ise especially when c onduc tivit y and mag netic pr oper ties
of the g r ound is t oo in t ense . Oper a tion of the devic e o v er such g r ound is made possible
b y selec ting the best oper a ting mode and using pr oper g r ound balanc e , gain, iSA T and
thr eshold settings .
S t on e s an d r oc k s o r c a v i t i e s i n si d e th e g r o u n d a r e a s im p or t an t as t h e g r ou n d it s e l f i n r e g a r ds
t o t h e se ar ch a nd t a r g e t de t e c t io n q u a l it y .
S oi l a n d r oc k s h a v e t w o d if f e r e n t p r op er t i e s ju s t li ke t h e t ar g e t s y o u ar e se ar c h in g f o r . O n e
o f t h e m i s th e i n t e n s i t y a nd t h e o t h e r o n e i s t h e c o n d u c t i v i t y - ma g n e t ic p e r m e a b ili t y r a t i o
a n d t h e s e t w o p r op e r t i e s a r e i n d e p e n d e n t f r om e a ch ot h e r . I n t h i s m an u a l , t he c o n d u c t i v i t y
- m ag n e t ic p e r m e a b i li t y r a t i o w i l l b e r ef e r r e d t o a s I D i n s h o r t . H i g h m ag ne t i c p e r m e ab i l i t y ,
l o w c o n d u c t i v i t y r e s u l t s in l o w I D . S o i l o r r o ck s c an b e h i g h l y p e r me ab l e an d h a v e lo w o r h ig h
I D s a s w el l . I f t h e c on d u c t i v i t y i n cr e as e s r ela t i v el y t o m a g n e t i c p e r m e ab i li t y t h e n t h e I D wil l
a ls o in cr e a se .
H o t r o c k s a r e c l a s s i f i e d as n e g a t i v e o r p o s i t i v e b as e d o n t h e ir I D b e i n g l o w o r h ig h i n c o m -
p a r i s o n t o t h e I D o f t h e so i l t h e y a r e i n . O n e o r b o t h o f t h e t y p e s m a y b e p r es e n t i n a f i e l d .
T h e n eg a t i v e a n d p o s i t i v e e ff e c t s m e n t i o n e d h e r e wi l l o n l y b e v a l i d i f g r o u n d b al a n c i n g
i s p r o p e r l y d o n e o n t h e e x i s t i n g g r o u n d . O t h e r w is e , s o i l i t s e l f wi l l n o t a c t d if f e r e n t l y f r o m
h o t r o c k s i n t er m s o f I D . I n ' ' T r a c k i n g ' ' h o w e v e r , c o n d i ti o n s w i l l d i f f e r . T h e r e f o r e , t h e e f f e c t s
o f r o c k s i n t r a c k i n g w il l b e d i s c u s s e d s e p ar a t e l y . H e r e w e a r e r e f e r r i ng t o a p r o p e r g r ou nd
b a la n c e wi t h o u t t r a c k i n g .
P ositiv e r ocks ac t just like metal and pr oduc e a metal sound . I n the G ener al S ear ch M odes
( GEN and GEN (D )) they pr oduc e a “ zip zip ” sound when the sear ch c oil is mo v ed o v er them.
I f the sig nal is str ong enough, the devic e ma y pr oduc e an ID f or these r ocks . Nega tiv e r ocks
in the G ener al S ear ch modes , pr oduc e a long “ boing ” sound when the sear ch c oil is mo v ed
o v er them. T he devic e does not g iv e an ID f or these r ocks ev en if the sig nal is str ong .
P os it i v e r o ck s p r o v i d e a t yp i c al m e t al so u n d i n d i s cr i m i n a t i o n m od e s . Ne g a t i v e r o c k s d o n o t
p r o vi d e a so u n d i n d i s cr i m i n a t i o n m o d es ( e x c e p t f or r a r e cas e s of f al s e s i g na l s ) .
A t higher settings of iSA T , ther e will be no change in the sounds of positiv e or nega tiv e hot
r ocks . A s the iSA T v alue is decr eased , the sound of positiv e hot r ocks will r emain the same
but the nega tiv e hot r ocks ma y g iv e a thinner beep sound inst ead of the boing sound .
T her ef or e , y ou can make a decision b y list ening t o the audio r esponses pr oduc ed b y the
devic e in the field . I f y ou r ec eiv e a metal sound , it means tha t y ou either det ec t ed a positiv e
r ock or a piec e of metal . I f y ou r ec eiv e a str ong sig nal and a stable ID , y ou can distinguish
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 .
