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Q U A L I T Y
Fisher detectors are renowned for their quality.
Gemini-3
Each detector is hand crafted in the USA with pride.
Deep Search, Two Box Metal and Mineral Detector
PERFORMANCE
Treasure Hunters worldwide rely on Fisher.
Our detectors are durable, dependable, and search deeper..
REPUTATION
Fisher produced the first patented metal detector in 1931. For
over 70 years, the Fisher logo has been a mark of excellence.
5 - YEAR LIMITED WARRANTY
Fisher believes in the products they produce and
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CONTENTS SPECIFICATIONS About Your Gemini-3 ............................................................... pg. 3 Basic Theory of Operation ....................................................... pg. 4 Notes Depth .........................................................................................pg. 5 Transmitter .................................................................................pg. 6 1. Subject to improvement or modification without notice. 2. Approximate. Receiver .......
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SPECIFICATIONS ABOUT YOUR DETECTOR 2 Two-box metal detectors have long been used by Dimensions prospectors, geologists, treasure hunters and public utility Length on handle ............................................................49 1/2 inches companies to locate large, deep objects, ore vein, pipes Transmitter-Receiver Box Assembly and cables. Fisher Research Laboratory is the recognized .................................................9 1/4 x 12 x 6 inches(23.5 x 30 x 15 cm) leader in
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Where To Use Your Metal Detector In The U.S. BASIC THEORY OF OPERATION The GEMINI-3 was engineered to detect conductivity National Forest and Federal Lands—Metal detecting is allowed only by special permit acquired from the federal government. changes in the earth over which it is carried. Hence, a positive Each area has a district office. response by the GEMINI-3 indicates the presence of a metal Corps of Engineers, Lakes, Shorelines and Lands—Permission has object, ore vein or mineral
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TREASURE HUNTERS’ CODE OF ETHICS DEPTH LETS PRESERVE OUR TREASURED SPORT! The GEMINI-3 was designed to locate large, deep objects such as an iron chest, pipe or an ore vein. It will not detect small coin- sized objects. A quart jar full of coins, however, may be detected Laws governing the use of metal detectors are becoming one-to-three feet deep. A 55-gallon drum may be detected as more and more common. In many countries, the use of metal deep as 10 feet. A very large object, like an
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BATTERY REPLACEMENT TRANSMITTER Power Switch: Pull out switch turns on power. 1. Turn either instrument (Transmitter and Receiver) over on its face and remove access plate with coin or large Ground Plate Jack: Used with the optional Ground Plate Assembly blade screwdriver. for the Conductive Trace Mode. 2. Lift the battery pack out carefully. Turn the battery Battery Level Meter: Gives a visual indication of battery strength. pack slightly, unsnap the battery connector and slip off the
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RECEIVER PROSPECTING TIPS Sources of Error Speaker: Provides audible indication of the receiver signal for The most common nonproductive zones of balancing and detecting. conductivity are: Meter: Provides visual indication of the Receiver signal response for 1. Dissolved mineral salts - Mineral salts become balancing and detecting. Also used as a battery test indicator. conductive when dissolved in water. As a result, the Sensitivity Control: Used to control sensitivity level. The cir
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SEARCHING PROSPECTING TIPS Mapping Narrow Scan Inductive Search When an area of high conductivity is encountered, This mode of operation is performed by a single operator using outline and stake it by crossing and recrossing, using the 3-piece handle. It is the best method for locating small or short the Narrow Scan Inductive Search mode. It will be objects (chest, coin-jar, rifle, etc.). However, it is also an effective noted that in and near the conductive zone, a way to locate pipes,
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TRACING SEARCHING Tuning Tuning 1. Set the transmitter: 1. Set the transmitter: Power: ON Power: ON 2. Set the Receiver: 2. Set the receiver: Power: ON Power: ON Sensitivity: 7 Sensitivity: ZERO You should get a strong audio tone and meter 3. Slowly increase the SENSITIVITY control until the indication at this point. audio signal is heard, then reduce SENSITIVITY until CAUTION: Never attempt to tune the GEMINI-3 in the the audio just disappears. This is the point
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SEARCHING TRACING 7. You are ready to search when the BALANCE knob Operating is adjusted within the 1/8- to 1/4-turn silence (null) 1. Once the two starting points have been established and space. This is extremely important! If this procedure the receiver tuned, walk away from the transmitter in is not followed correctly, the GEMINI-3 will either the assumed direction of the buried conductor. constantly give false audio and meter readings 2. Hold the receiver vertically to maintain a
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TRACING SEARCHING 5. For even more accurate pinpointing of short objects, Inductive Trace (i.e., a pipe, cable, etc.) approach the test object The Inductive Trace mode is usually used to trace at right angles from your previous direction. Mark the a long object (pipe, ore vein, etc.) that shows no ground as you did before. Your test object should be exposed portions, but two starting points are known. about centered between four marks. Set Up 6. To establish the path of a pipe, cable,
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SEARCHING SEARCHING Wide Scan Inductive Search 3. Slowly increase the SENSITIVITY control until the audio This mode of operation is the preferred method for signal is heard, then reduce SENSITIVITY until the audio searching a large area quickly. Two operators are just disappears. This is the point at which “air coupling” required and the handle assembly is not used. has been eliminated. The Wide Scan Inductive Search mode is practical Operating only when searching for ore veins, pipe
