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11

SEARCHING

5

. For even more accurate pinpointing of short objects, 

(i.e., a pipe, cable, etc.) approach the test object 

at right angles from your previous direction. Mark the 

ground as you did before. Your test object should be 

about centered between four marks. 

6

. To establish the path of a pipe, cable, or other long 

conductor,  pinpoint  two  more  locations  15-20  feet 

apart. From these three locations you should be able to 

draw a straight line (unless the pipe isn’t straight). Careful 

additional locations may be necessary if no prints (maps 

of underground lines) of the area are available. 

7

.  It  may  be  necessary  to  reduce  sensitivity  with  the 

SENSITIVITY knob when the pipe or cable is large and/

or shallow. If the meter needle has peaked and sound 

is at a high level, you will want to bring the sensitivity 

down to see the peak of the needle at a point less 

than 100 as you move in half or quarter steps back 

and forth to get your peak reading. 

8.

  If  at  all  possible,  practice  over  some 

buried targets of known size and depth. 

9

.  There  are  several  things  to  consider 

when locating buried objects: 

a. Precise location depends on operator skill. 
b.  Position  of  the  ground  marks  does  not 

indicate size of the object or its path. 

c.  More  than  one  metal  object  may  cause 

a  wider  or  stronger  response  than 
expected. 

d. Deeper targets may not produce a signal 

until the operator has passed directly over 
them. 

e.  Reducing  the  receiver  SENSITIVITY  control 

will narrow the area between the ground 
marks for more precise pinpointing. 

f.  Small  or  deeply  buried  objects  such  as  a 

cache  of  coins,  require  a  tight,  closely 
traversed search pattern. Large or shallow 
objects can be located successfully with 
a  larger,  more  widely  traversed  search 
pattern. 

Figure 6. 

Handle strap: Using 

the handle strap increases 
depth; however, it may be 
difficult to tune the GEMINI-3 
this close to highly mineralized 
ground.

14

TRACING

Inductive Trace

  The Inductive Trace mode is usually used to trace 

a  long  object  (pipe,  ore  vein,  etc.)  that  shows  no 

exposed portions, but two starting points are known. 

        Set Up

Locate two points along the conductive object at 

least  30  feet  apart  as  described  in  the  Wide  Scan 

or  Narrow  Scan  Inductive  Search  sections.  The 

transmitter and receiver should be in line with each 

other, both facing the same direction. The transmitter 

should be on the ground and the receiver should be 

held by the operator. 

        Tuning

1. 

Set the transmitter: 

    Power: ON 

2. 

Set the receiver: 

    Power: ON 

    Sensitivity: ZERO 

3.  I

ncrease  the  receiver  SENSITIVITY  control  until  you 

have  an  audio  response  and  at  least  a  mid-scale 

meter deflection. 

4. 

Determine  that  you  are  not  direct  air  coupling  by 

moving the receiver back and forth. The audio meter 

indications  should  peak  over  the  object.  No  peak 

will  be  observed  if  the  receiver  is  too  close  to  the 

transmitter and direct air coupling is occurring.

Figure 8. 

Inductive Trace

Содержание Gemini-3

Страница 1: ...Gemini 3 Operating Manual 2 Box Metal and Mineral Detector for Deep Search and Cache Locating 1813...

Страница 2: ...ing pg 14 Inductive Tracing pg 14 Set Up pg 14 Tuning pg 14 Operation pg 15 Conductive Trace pg 15 Set Up pg 15 Tuning pg 16 Operation pg 16 Prospecting Tips pg 17 Mapping pg 17 Locating Placer Deposi...

Страница 3: ...1950s The new GEMINI 3 goes 10 to 20 percent deeper than its predecessor It will trace most pipes and ore veins at least 50 percent farther and the new crystal controlled circuitry is rock stable The...

Страница 4: ...uency RF signal down to a conductive object and generate an electromagnetic field around that object When used in any of the Inductive modes the RF signal travels through the ground to the object When...

Страница 5: ...per than 5 feet in highly mineralized ground 2 Size and Depth of Object A 4 inch diameter target will produce signal 64 times stronger than a similar 1 inch diameter target at the same depth An object...

Страница 6: ...e 2 Transmitter Power Switch Pull out switch turns on power Ground Plate Jack Used with the optional Ground Plate Assembly for the Conductive Trace Mode Battery Level Meter Gives a visual indication o...

Страница 7: ...sensitivity level The circled 7 indicates the starting level used for Narrow Scan Inductive Search Mode Headphone Jack Accepts stereo or monaural headphones and silences speaker when headphones are p...

Страница 8: ...Tighten the two center knobs finger tight until there is no wobble Place the transmitter on its back and insert the end of the handle with the single brass shaft into the V shaped slot Turn the knob...

Страница 9: ...ome asphalt you may not be able to use it with the strap fully lengthened You will know this during tuning if you cannot reach a silence null Not reaching a null can also indicate the presence of near...

Страница 10: ...ument properly tuned and held in the hand or suspended by the strap slowly walk directly toward your test object Keep the handle as level and steady as possible while in motion or the tuning may chang...

Страница 11: ...han 100 as you move in half or quarter steps back and forth to get your peak reading 8 If at all possible practice over some buried targets of known size and depth 9 There are several things to consid...

Страница 12: ...e together direct air coupling will result meaning the receiver is detecting the Transmitter signal directly through the air instead of through a buried conductor Set Up Two operators line up at least...

Страница 13: ...ly the same time the receiver tone and meter will rise to indicate its presence The receiver operator should alert the transmitter operator that they have detected a conductive object 3 The receiver o...

Страница 14: ...oth facing the same direction The transmitter should be on the ground and the receiver should be held by the operator Tuning 1 Set the transmitter Power ON 2 Set the receiver Power ON Sensitivity ZERO...

Страница 15: ...pipe each time a T junction or lateral is encountered the signal will split and weaken Conductive Trace This is the best method for tracing a single pipe in the presence of other pipes A portion of t...

Страница 16: ...rating 1 Locate the buried pipe by circling the contact point keeping the receiver in line with the contact at all times Stay at least 30 feet from the transmitter 2 Once the pipe has been located by...

Страница 17: ...and plotted on a map The map should include all creek bottoms gullies outcrops and other physical features The ideal map on which to plot the conductive zones is a topographic and geological map of t...

Страница 18: ...creek beds usually have no economic value or importance in determining the geology 6 Conductive debris Unexpected high readings are often due to highly conductive debris near the surface such as scra...

Страница 19: ...s compartment and do a battery test Refasten the access plate Both the transmitter and receiver will work from 30 to 40 hours on a set of 8 standard quality carbon zinc batteries Alkaline batteries wi...

Страница 20: ...ivate property without the owner s permission Take care to refill all holes and leave no damage Remove and dispose of any and all trash and litter found Appreciate and protect our inheritance of natur...

Страница 21: ...to use your detector Bureau of Land Management BLM Lands Some areas are open for metal detecting and some are not Always check with the district office City or County Park Lands Most are open to meta...

Страница 22: ...dle 1 7 lbs 75 k Frequency RF Search and Trace 81 92 KHz Crystal Controlled Audio Target Response V C O Operating Modes Search 1 Narrow Scan Inductive 2 Wide Scan Inductive Trace 1 Inductive 2 Conduct...

Страница 23: ...oratory does not warrant suitability to specific use Fisher Research Laboratory shall in no event be liable for any direct incidental consequential or indirect damages SPECIFICATIONS Using headphones...

Страница 24: ...this belief with a 5 year limited warranty Proof of purchase is required to make a claim under this warranty NOTE TO CUSTOMERS OUTSIDE THE U S A This warranty may vary in other countries check with yo...

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