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Summary of Contents for Fisher Labs Gemini-3
- Page 1 Gemini-3 Deep Search, Two Box Metal and Mineral Detector Operating Manual F I S H E R R E S E A R C H L A B O R A T O R Y...
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Page 2: Table Of Contents
CONTENTS About Your Gemini-3 ............... pg. 3 Basic Theory of Operation ............pg. 4 Depth ..................pg. 5 Transmitter ................. pg. 6 Receiver ..................pg. 7 Searching................pg. 8 Narrow Scan Inductive Search ..........pg. 8 Set Up -Narrow Scan Inductive Search ......pg. 8 Tuning -Narrow Scan Inductive Search ...... -
Page 3: About Your Gemini-3
You might think it would be difficult to improve on a product that has been in a constant state of development for so many years. But the fact is, the GEMINI-3 is probably the biggest leap forward in two-box design since it replaced vacuum tubes with transistors back in the 1950s. -
Page 4: Basic Theory Of Operation
The function of the GEMINI-3 Transmitter is to send a radio frequency (RF) signal down to a conductive object and generate an electromagnetic field around that object. -
Page 5: Depth
10 feet. A very large object, like an automobile, may be detected at 20 feet or more. The ability of the GEMINI-3 to detect objects at various depths depends on several factors: 1. Ground Mineralization: The penetrating power of the... -
Page 6: Transmitter
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 of battery strength. Replace batteries if below 5 on meter. Battery Level Meter Power Switch Ground Plate... -
Page 7: Receiver
RECEIVER Speaker: Provides audible indication of the receiver signal for balancing and detecting. Meter: Provides visual indication of the Receiver signal response for balancing and detecting. Also used as a battery test indicator. Sensitivity Control: Used to control sensitivity level. The circled “7” indicates the starting level used for Narrow Scan Inductive Search Mode. -
Page 8: Searching
SEARCHING Narrow Scan Inductive Search This mode of operation is performed by a single operator using the 3-piece handle. It is the best method for locating small or short objects (chest, coin-jar, rifle, etc.). However, it is also an effective way to locate pipes, cables and ore veins. -
Page 9: Tuning -Narrow Scan Inductive Search
Sensitivity: 7 You should get a strong audio tone and meter indication at this point. CAUTION: Never attempt to tune the GEMINI-3 in the presence of metal objects likes cars, metal walls, roofs or heavy metal reinforcements in any structure. Their presence will make proper balancing impossible. -
Page 10: Operation -Narrow Scan Inductive Search
BALANCE knob and/or the SENSITIVITY control. Operating Test your GEMINI-3 in an area you are reasonably sure is free of large buried objects. Scatter some metal objects, such as a tool box, piece of pipe. . With the instrument properly tuned and held in the hand or suspended by the strap, slowly walk directly toward your test object. - Page 11 Large or shallow depth; however, it may be objects can be located successfully with difficult to tune the GEMINI-3 this close to highly mineralized a larger, more widely traversed search ground. pattern.
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Page 12: Wide Scan Inductive Search
SEARCHING Wide Scan Inductive Search This mode of operation is the preferred method for searching a large area quickly. Two operators are required and the handle assembly is not used. The Wide Scan Inductive Search mode is practical only when searching for ore veins, pipes or cable 40 feet long or more. -
Page 13: Operation -Wide Scan Inductive Search
SEARCHING 3. Slowly increase the SENSITIVITY control until the audio signal is heard, then reduce SENSITIVITY until the audio just disappears. This is the point at which “air coupling” has been eliminated. Operating 1. Keeping the receiver and transmitter sections in line, the two operators can now walk their predetermined search pattern. -
Page 14: Tracing
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. -
Page 15: Operation -Inductive Trace
TRACING Operating 1. Once the two starting points have been established and the receiver tuned, walk away from the transmitter in the assumed direction of the buried conductor. 2. Hold the receiver vertically to maintain a peak signal or horizontally, face up, to maintain a null or minimum signal. -
Page 16: Tuning -Conductive Trace
TRACING Tuning 1. Set the transmitter: Power: ON 2. Set the receiver: Power: ON Sensitivity: ZERO 3. Slowly increase the SENSITIVITY control until the audio signal is heard, then reduce SENSITIVITY until the audio just disappears. This is the point at which air coupling has been eliminated. -
Page 17: Prospecting Tips
Both of these mineral substances are definitely conductive, and may be detected by the GEMINI-3. It is through the detection of these minerals that the placer gold may be located. -
Page 18: Sources Of Error
As a result, the presence of saline water or water saturated soil high in salt content, may render the GEMINI-3 useless. 2. Rough terrain - In very rough terrain it may be difficult to maintain the GEMINI-3 parallel to the ground, resulting in frequent false signals. -
Page 19: Battery Replacement
BATTERY REPLACEMENT 1. Turn either instrument (Transmitter and Receiver) over on its face and remove access plate with coin or large blade screwdriver. 2. Lift the battery pack out carefully. Turn the battery pack slightly, unsnap the battery connector and slip off the sleeve. -
Page 20: Treasure Hunters' Code Of Ethics
TREASURE HUNTERS’ CODE OF ETHICS LETS PRESERVE OUR TREASURED SPORT! Laws governing the use of metal detectors are common in some areas. In many countries, the use of metal detectors is illegal or severely restricted. DON’T LET THIS HAPPEN IN YOUR COUNTRY! •... -
Page 21: Where To Use Your Metal Detector In The U.s
Where To Use Your Metal Detector In The U.S. National Forest and Federal Lands—Metal detecting is allowed only by special permit acquired from the federal government. Each area has a district office. Corps of Engineers, Lakes, Shorelines and Lands—Permission has been granted only on predisturbed sites, such as beaches and attached swimming areas. -
Page 22: Specifications
SPECIFICATIONS Dimensions Length on handle ............49 1/2 inches Transmitter-Receiver Box Assembly ..........9 1/4 x 12 x 6 inches(23.5 x 30 x 15 cm) Weight Complete ................7 lbs. (3.2 k) Transmitter ................2.4 lbs. (1.1 k) Receiver ................2.9 lbs. (1.3 k) Handle ................1.7 lbs. (.75 k) Frequency RF Search and Trace ......81.92 KHz Crystal Controlled .......... -
Page 23: Using Headphones
SPECIFICATIONS Notes 1. Subject to improvement or modification without notice. 2. Approximate. 3. Voltage Controlled Oscillator. Volume and pitch both increase as target is approached for easier, more accurate pinpointing. 4. With optional ground plate assembly. 5. Optional stereo/mono headphones. 6. - Page 24 Q U A L I T Y Fisher detectors are renowned for their quality. Each detector is hand crafted in the USA with pride P E R F O R M A N C E Treasure Hunters worldwide rely on Fisher. Our detectors are durable, dependable, and search deeper..
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