Fisher Labs F75 User Manual

Fisher Labs F75 User Manual

Multipurpose metal detector
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The F75 is a multipurpose metal detector. Its most popular uses are coinshooting and relic
hunting, and it is also well- suited to gold prospecting.
PRODUCT FEATURES
• Light weight and well-balanced: best ergonomically engineered detector in the industry.
• Intuitive menu-driven user interface
• Large LCD screen
• Visual indicators of important values such as:
Target Identification
Target Confidence
Target Depth (both running-depth and pinpoint-depth)
Ground Mineralization
• Multiple Search Modes:
Discrimination
Static All-Metal
Motion All-Metal
• Trigger-actuated FASTGRAB
• Waterproof 11-inch open-frame BiAxial™ searchcoil
• Trigger-actuated target pinpointing with variable audio pitch
• Fully Adjustable Arm Rest
• Display backlight for night and low-light conditions
• Notch and discrimination controls
• Covers provided for both the control housing and battery box.
If you have any questions, or need assistance with your metal detector,
Call 1-915-225-0333, and ask for Fisher Hobby Technical Service
Copyright Fisher Research Labs, Inc., February 28, 2007

Metal Detector

Users Manual
ground balancing with manual override

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Questions and answers

gary sturgeon
February 13, 2025

we are looking for gold coins, what is the best setting as there is a lot of scrap metal in the ground and its going off everywhere?

1 comments:
Mr. Anderson
February 13, 2025

To find gold coins in areas with a lot of scrap metal using the Fisher Labs F75 metal detector, follow these settings:

1. Sensitivity: Set it high for maximum depth, but reduce if experiencing excessive noise.
2. Ground Balance: Perform ground balancing first to minimize interference from mineralized soil.
3. Discrimination Mode: Use discrimination to filter out common trash metals like iron and aluminum pull-tabs.
4. Operating Frequency: The F75 operates at 13 kHz, which is suitable for gold and coins.
5. Searchcoil Positioning: Use the 11-inch elliptical Bi-Axial searchcoil for better detection depth.
6. Pinpointing Mode: After detecting a target, use the trigger switch to pinpoint its exact location.

These settings help maximize detection of gold coins while reducing interference from scrap metal.

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Summary of Contents for Fisher Labs F75

  • Page 1: Metal Detector

    Metal Detector Users Manual The F75 is a multipurpose metal detector. Its most popular uses are coinshooting and relic hunting, and it is also well- suited to gold prospecting. PRODUCT FEATURES • Light weight and well-balanced: best ergonomically engineered detector in the industry.
  • Page 2: Table Of Contents

    Quick-Start ……………………………………… 4 Mechanicals Assembly Instructions ………………………….. 5 Mechanicals………………………………………6 Arm Rest adjustment …………………………… 6 Using Headphones (not included) ……………… 6 Introduction to the F75 General information ……..……………………… 7 Controls…………………..……………… ………8 Menu System..…………………………………... 9 Ground Balancing….………………………...10-12 Motion All Metal Mode …………………………13 Static All Metal Mode……………………………14...
  • Page 3: Specifications

    SPECIFICATIONS Mechanical: S-rod with electronics housing mounted on handgrip, 3-piece breakdown, batteries under elbow, 2-way armrest adjustment — forward/backward & around forearm. Searchcoil: 11” (28 cm) open- frame elliptical double-D, waterproof. Batteries: 4 AA, alkaline (included). Weight: 3.5 pounds (1.6 kg) with alkaline batteries installed. Static Balance : force in vertical plane normal to elbow 0.47 pounds (0.22 kg).Varies with adjustment and user’s stance and arm/hand...
  • Page 4: Quick-Start

    Turn the knob, located under the armrest, fully clockwise. This turns the machine on and sets audio volume to maximum. When first turned on, the F75 starts out in the Discrimination mode, with: Sensitivity preset to 60 Discrimination Level preset to 10...
  • Page 5: Mechanicals Assembly Instructions

    ASSEMBLY 1. Remove all components from box. 2. Attach searchcoil to lower rod by lining up the holes. Notice that the lower rod is supplied with only one rubber washer. It is designed to work with only one washer for maximum stability. Push coil knob through hole and tighten knob gently.
  • Page 6: Mechanicals

    HEADPHONES (not included) The F75 is equipped with a standard ¼-inch stereo headphone jack at the rear of the unit, located under the elbow as you hold the detector for use. Any headphone with a ¼” stereo jack should work.
  • Page 7: Introduction To The F75

    ID considered essential in searching for coins. The F75 operates at 13 kHz for good sensitivity to gold nuggets and jewelry as well as to coins. The F75 comes with an 11- inch elliptical Bi-Axial searchcoil for maximum detection depth in mineralized soils.
  • Page 8: Controls

    Knob position has no effect on detector’s sensitivity or susceptibility to noise from electrical interference The F75 has two controls on the front panel, MENU and SETTINGS. MENU Pushbutton (Red button on right of the front panel) Push the MENU button to: 1.
  • Page 9: Menu System

    THE MENU SYSTEM The entire menu is printed on the LCD display. The display highlights the mode and settings which are in use. There are three search modes, Static All Metals, Motion All Metals, and Discrimination. To change between an All Metals modes and Discrimination mode, the top line of the menu system must be highlighted.
  • Page 10: Ground Balancing

    GROUND BALANCING What is Ground Balancing? All soils contain minerals. Signals from ground minerals are often tens or hundreds of times as strong as the signal from a buried metal object. The magnetism of iron minerals, found in nearly all soils, causes one type of interfering signal. Dissolved mineral salts, found in some soils, are electrically conductive, causing another type of interfering signal.
  • Page 11 GROUND BALANCING (continued) MANUAL GROUND BALANCING (continued) The Fe bar graph on the LCD display indicates the amount of magnetic mineralization. The searchcoil must be in motion to measure Fe . The most accurate measurement is obtained by pumping the searchcoil, as in the Ground Balancing procedure. The two-digit G.B.
  • Page 12 GROUND BALANCING (continued) Positive and Negative Response The purpose of ground balancing is to adjust the metal detector to ignore ground minerals. If the setting is incorrect, ground minerals will give either a positive or a negative response, depending on which direction the adjustment is off. POSITIVE RESPONSE If the G.B.
  • Page 13: Motion All Metal Mode

    MOTION ALL METAL MODE The Motion All Metal mode is more sensitive and offers better feel than the Discrimination mode, and is used to find all metal objects present in the ground. The searchcoil must be in motion for objects to be detected. This is a single filter search mode similar to the “fast autotune”, “SAT”, or “P4”...
  • Page 14: Static All Metal Mode

    STATIC ALL METAL MODE This mode is useful for finding large, deep objects, i.e. larger than a coin and deeper than 12 inches (30cm). STATIC functions the same as PinPoint but occupies a different position on the user interface. The audio signal gets stronger as the searchcoil approaches the ground.
  • Page 15: Discrimination Mode

    DISCRIMINATION MODE The Discrimination Mode is used to eliminate trash metal objects from detection, e.g. nails, aluminum foil, or pull-tabs. The searchcoil must be in motion for metal objects to be detected. Discrimination incurs some loss of sensitivity to small or deep objects. SENSITIVITY This controls the signal gain, and is adjustable from 1 to 99.
  • Page 16 DISCRIMINATION MODE (continued) NOTCH Unlike Discrimination Level, which eliminates all targets from the left of the scale to the right, NOTCH can eliminate and re-include targets within the scale displayed at the top of the display. Inclusion or exclusion of target ranges is indicated with a half-crossed or crossed icon. To demonstrate how to set a notch, follow this instruction at first use.
  • Page 17 DISCRIMINATION MODE (continued) NUMBER OF TONES (# OF TONES) This menu selection allows you to select the number of audio tones emitted by the detector. Different search conditions, search objectives, or personal preference will determine how many tones you want to hear. With the below settings, you can decide to hear the same tone, regardless of the target category, or have different categories of targets induce different tones.
  • Page 18 ID and audible response. By making the audio and visual systems independent, the F75 allows each system to do what it does best. The audio is optimized for quick response and target feel, whereas the visual system...
  • Page 19: Pinpoint Feature

    PinPoint Feature After a buried target has been located using the All Metal or Discrimination modes, you want to pinpoint the exact location of the target in order to facilitate its recovery. Accurate target pinpointing will minimize digging. Activate the PinPoint feature by pulling the trigger switch located under the housing. Unlike the All Metal and Discrimination modes, PinPoint does not require motion to detect metal.
  • Page 20: Lcd Visual Display

    LCD VISUAL DISPLAY In normal operation, when the searchcoil passes over a metal object, the electrical signature (2-digit I.D.) of the metal object is displayed on the numeric display for 4 seconds, unless superceded by another detected object. On a given buried object, the number will bounce around if the signal is weak or if the amount of ground mineralization is high.
  • Page 21: Target Indicators

    LCD VISUAL DISPLAY (continued) Since different metal objects can produce similar signals, and since minerals in the soil can distort the signals, the probable target ID's are just that -- probable. There is no way of knowing for sure what's buried other than to dig it up. Experienced metal detector users have a rule of thumb -- "when in doubt, dig".
  • Page 22: Battery Indicator

    LCD VISUAL DISPLAY (continued) BATTERY CONDITION INDICATOR Fresh alkaline batteries will illuminate all three bars. When no bars are displayed and the batteries are about to go dead, the BATT legend will start flashing. The detector should operate for about 30 minutes from the time the indicator starts flashing. If using NiMH rechargeable batteries, the display will remain stuck on the second or third bar for most of the battery life;...
  • Page 23: Frequency Shifting

    Each actuation will shift the frequency by one value. The LCD will display the frequency, from F1 to F7. F1 is the lowest frequency. The default frequency is F4. The F75 will retain any change in the frequency setting, even after powered off.
  • Page 24: Capabilities & Limitations

    CAPABILITIES AND LIMITATIONS DEPTH The F75 can detect U.S. coins to a depth of up to 15-16 inches (37-40cm) under good conditions. Large objects (55 gallon drums, manhole covers, etc.) can be detected to a depth of up to several feet (1-2 meters).
  • Page 25 In order to most accurately verify a detected target with most other metal detectors, users will narrow their sweep and loiter over the top of the target. The F75 is different. The F75's quick response and advanced signal sampling system produces the most accurate target IDs with deliberate (shoulder width) sweeps all the way across the target, even if there are other targets nearby.
  • Page 26: Capabilities & Limitations

    CAPABILITIES AND LIMITATIONS (continued) STEEL BOTTLE CAPS & FLAT IRON TRASH Modern motion-type target ID metal detectors usually have difficulty consistently identifying steel bottle caps and other flat iron trash objects. Double-D searchcoils also have a reputation for having difficulty distinguishing steel bottle caps from coins, and for being unable to eliminate steel bottle caps from detection.
  • Page 27: Search Techniques

    Pinpointing With the Trigger Switch When you turn the F75 on, the ground balance setting is preset to give a positive response on nearly all soils. This means that if you are pulling the pinpoint trigger, the audio tone will get louder as you lower the searchcoil to the ground.
  • Page 28: Estimating Target Size And Depth

    SEARCH TECHNIQUES (continued) Estimating Target SIZE, DEPTH, and SHAPE When the trigger is pulled to activate Pinpoint, the LCD displays estimated depth. The estimate is based on the presumption that it is a coin-sized target. But what if it is not a coin-sized target? The most common example is that of an aluminum can.
  • Page 29: False Signals And Chatter

    ID numbers higher than would be obtained in an air test. This tendency is connected with the F75’s enhanced see-through ability – that is, the ability to find valuable targets in an area where there is a lot of iron trash.
  • Page 30 SEARCH TECHNIQUES (continued) NUISANCE BURIED OBJECTS In some areas there is a lot of metallic trash which produces weak signals. These could include deeply buried objects, little bits and pieces of rusty iron and corroded foil. These items can be detected, but are difficult to pinpoint due to their depth and small size. When you dig and find nothing, it may seem like the machine is beeping at nothing even though there is actually something there.
  • Page 31: Adjusting Sensitivity

    -- “don’t dig non-repeatable signals”. Using the sensitivity control When the F75 is first turned on, the Sensitivity is at a medium setting appropriate for most coinshooting. For relic hunting or gold prospecting, higher Sensitivity settings are usually preferred.
  • Page 32: Tips On Ground Balanc Ing

    SEARCH TECHNIQUES (continued) Tips on ground balanc ing When the F75 first turns on, the ground balance setting is preset to 90. This will give a positive response on nearly all soils. If you search in the Discrimination mode, you will probably not have to balance to the ground.
  • Page 33: Detecting Activities

    Detecting Activities Coinshooting Coinshooting is searching for coins, usually in places like parks, schoolyards, church lawns, and people's yards. In most places where coins are likely to be found, there is also a lot of aluminum trash like pull-tabs and bottle caps, as well as steel bottle caps and often nails.
  • Page 34: Gold Prospecting

    The ground balancing and Fe bar graph features of the F75 can be used to map the soils of a site. In this way you might determine which areas have been dug, backfilled, or subjected to fire.
  • Page 35 Detecting Activities (continued) Hillsides are the best areas for gold prospecting using a metal detector, because hillsides cannot be cleaned out by panning and dredging the way streams can. Also, gold on hillsides, not far from its source vein, tends to be larger, and hence more readily detected, than alluvial (placer) gold which tends to get pounded to pieces and worn away as it rolls along the streambed with gravel during floods.
  • Page 36: Cache Hunting

    Detecting Activities (continued) Cache Hunting A cache (pronounced "cash") is an accumulation of money, jewelry, gold, or other valuables, which someone has hidden. When people bury a cache, they usually put it in a strongbox or in a jar. To search for a cache, you first need a reason to believe the cache may exist.
  • Page 37: Salt-Water Hunting

    Salt Water Hunting Salt water is highly conductive, and produces a strong signal which is like that of metal. The F75 is not specifically designed for top performance in salt water, but can be used in this environment. If you desire to search in or over salt water, the following measures will usually be sufficient to silence the salt water response while retaining acceptable sensitivity: 1.
  • Page 38: Warranty

    Proof of Purchase is required make a claim under this warranty. Liability under this Warranty is limited to replacing or repairing, at our option, the metal detector returned, shipping cost prepaid to Fisher Labs. Shipping cost to Fisher Labs is the responsibility of the consumer.

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