QUALITY Gemini-3 Fisher detectors are renowned for their quality. 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.
CONTENTS About Your Gemini-3................................................................ pg. 3 Basic Theory of Operation........................................................ pg. 4 Depth.......................................................................................... pg. 5 Transmitter.................................................................................. pg. 6 Receiver..................................................................................... pg. 7 Searching...........
SPECIFICATIONS Dimensions 2 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 . ................................................
BASIC THEORY OF OPERATION Where To Use Your Metal Detector In The U.S. The GEMINI-3 was engineered to detect conductivity changes in the earth over which it is carried. Hence, a positive response by the GEMINI-3 indicates the presence of a metal object, ore vein or mineral that is more conductive than the surrounding rock or soil. National Forest and Federal Lands—Metal detecting is allowed only by special permit acquired from the federal government. Each area has a district office.
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! • Always check Federal, State, County and local laws before searching. • Respect private property and do not enter private property without the owner’s permission. • Take care to refill all holes and try not to leave any damage.
BATTERY REPLACEMENT 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. 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.
RECEIVER PROSPECTING TIPS Sources of Error The most common nonproductive zones of conductivity are: 1. Dissolved mineral salts - Mineral salts become conductive when dissolved in water. 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. 3.
SEARCHING PROSPECTING TIPS Narrow Scan Inductive Search Mapping 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. Set Up 1. Assemble the 3-piece handle by inserting each end piece into the center handle section. Tighten the two center knobs finger tight until there is no wobble.
SEARCHING TRACING Tuning Operating 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. 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.
SEARCHING TRACING 7. You are ready to search when the BALANCE knob is adjusted within the 1/8- to 1/4-turn silence (null) space. This is extremely important! If this procedure is not followed correctly, the GEMINI-3 will either constantly give false audio and meter readings (sensitivity too high), or no signals at all (sensitivity too low). The sensitivity will be correctly set and your GEMINI-3 will operate properly only when a 1/4- to 1/8-turn null has been achieved.
TRACING Inductive Trace Set Up SEARCHING 5. For even more accurate pinpointing of short objects, 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. (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.
SEARCHING 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.
SEARCHING 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.
TRACING Inductive Trace Set Up SEARCHING 5. For even more accurate pinpointing of short objects, 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. (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.
SEARCHING TRACING 7. You are ready to search when the BALANCE knob is adjusted within the 1/8- to 1/4-turn silence (null) space. This is extremely important! If this procedure is not followed correctly, the GEMINI-3 will either constantly give false audio and meter readings (sensitivity too high), or no signals at all (sensitivity too low). The sensitivity will be correctly set and your GEMINI-3 will operate properly only when a 1/4- to 1/8-turn null has been achieved.
SEARCHING TRACING Tuning Operating 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. 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.
SEARCHING PROSPECTING TIPS Narrow Scan Inductive Search Mapping 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. Set Up 1. Assemble the 3-piece handle by inserting each end piece into the center handle section. Tighten the two center knobs finger tight until there is no wobble.
RECEIVER PROSPECTING TIPS Sources of Error The most common nonproductive zones of conductivity are: 1. Dissolved mineral salts - Mineral salts become conductive when dissolved in water. 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. 3.
BATTERY REPLACEMENT 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. 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.
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! • Always check Federal, State, County and local laws before searching. • Respect private property and do not enter private property without the owner’s permission. • Take care to refill all holes and try not to leave any damage.
BASIC THEORY OF OPERATION Where To Use Your Metal Detector In The U.S. The GEMINI-3 was engineered to detect conductivity changes in the earth over which it is carried. Hence, a positive response by the GEMINI-3 indicates the presence of a metal object, ore vein or mineral that is more conductive than the surrounding rock or soil. National Forest and Federal Lands—Metal detecting is allowed only by special permit acquired from the federal government. Each area has a district office.
SPECIFICATIONS Dimensions 2 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 . ................................................
CONTENTS About Your Gemini-3................................................................ pg. 3 Basic Theory of Operation........................................................ pg. 4 Depth.......................................................................................... pg. 5 Transmitter.................................................................................. pg. 6 Receiver..................................................................................... pg. 7 Searching...........
QUALITY Gemini-3 Fisher detectors are renowned for their quality. 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.
