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Fisher F75 LIMITED Black Reader user manual

1. 32 Boost and Cache Locating Processes 32 33 Pinpointing targets 33 34 Estimating target size and depth 34 35 False signals and chatter 35 Adjusting 5 37 Tips on ground balancing 38 Detecting Activities Coinshooting ss ske k r tatere aker Ede 39 Relic Hunting Pi ees het d 40 41 Gold Prospecting 41 42 Cache Hunting ghee kid SA aed 43 Shallow Water 43 44 Saltwater Hunting 44 How metal detectors work 45 Treasure Hunter s Codd of 46 Warranty Specifications Mechanical Searchcoil Batteries Weight Static Balance Dynamic Balance Sweep Effort Operating Principle Operating Frequency Basic Sensitivity Lag Coefficient Reactive Overload Resistive Overload S rod with electronics housing mounted on handgrip 3 piece breakdown batteries under elbow 2 way armrest adjustment forward backward amp around forearm 11 28 cm open frame elliptical double D waterproof 4 AA alkaline not included 3 5 pounds 1 6 kg with alkaline batteries installed force in ver
2. heeled kjedet 8 Arm Rest 8 Using Headphones not 9 Introduction to the F75 General 10 Controls oe dk artet ees 11 12 Menu Systemes epai 13 Ground Balancing xs oe Sonia de 14 16 Motion All Metal 17 Static All Metal Mode 18 Discrimination Mode 19 23 PinPoint Feature sanse Ags Feb sin Ad ae A 24 LCD Visual Display ua hie ieee Ae a 25 27 Numeric Target Identification 25 Probable Target Identification 25 Depth Indicators sake etna dee dikene 26 Confidence Indicator 26 Oat dh died oo RB ah Lets 26 Battery Indicator 27 GB detour bar dated ae ear fa 27 Setting sate ethereal Lath te eee ee he 27 Messages umres tea Ce saag nr anbe KS Aase 27 Frequency Shitting ix ass isk emi ma atid dee 28 Capabilities amp Limitations 29 31 Tips amp Techniques Search Techniques How to sweep the
3. If the detector chatters while the searchcoil is not in motion the cause is either electrical interference or internal circuit noise due to a high sensitivity setting If the detector chatters or emits intermittent false signals in the field you are also probably experiencing electrical interference If you suspect electrical interference you may change the F75 s operating frequency This is a trial and error method to try to find a frequency different from the suspected source To shift frequencies 1 Hold the MENU button down Do not release the button 2 Push the trigger forward OR pull the trigger back to change the frequency Each frequency change requires a push of the MENU button Each actuation will shift the frequency by one value The LCD will display the frequency from F1 to F7 F1 is the lowest frequency And the default frequency The F75 does not retain changes in the frequency setting wnen powered off See the Search Techniques section of this manual for more information on electrical interference 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 Electrical interference from power lines and from electrical appliances and electronic equipment can reduce detection depth or cause audible interference making
4. characteristics of the Motion All Metal Mode are also modified these characteristics include less noise and a slower response speed In many situations you may prefer to do cache locating in the Motion All Metal Mode after first selecting the Cache Locating process in the Discrimination Mode WHAT YOU SEE VS WHAT YOU HEAR The visual target ID displayed on the LCD is based entirely on sampled processing the number displayed represents a snapshot of the target s identification as the searchcoil passes over the object When using these different processes or methods the detector s audible response may differ from the visual When using the different processes there is not a 100 correspondence between what you see and what you hear especially on buried targets where ground minerals influence target 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 provides the best numeric resolution of target ID Pin Point 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 motion All Metal and Discrimination mode
5. depends on the discrimination setting When searching in an All Metals mode if ground balance is properly set to cancel the ground and you sweep over a positive hot rock the rock will give a zip sound similar to that of a metal object NEGATIVE RESPONSE If the G B setting is too low a number the response of minerals will be negative When the searchcoil is lowered to the ground in PinPoint Stat or Motion All Metals mode the machine will be silent The machine will sound off as the searchcoil is lifted away from the ground What if anything you hear in discrimination mode depends on the discrimination setting When searching in Motion All Metals mode a negative hot rock will produce a boing sound after passing over it making it difficult to know where it is located It will not have the sound and feel of a metal object Metien 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 modes found in other detectors you might already be familiar with THRESHOLD Adjustable from 9 to 9 For maximum ability to hear the weakest signals adjust this background noise level high enough so that it is barely audible while the detector is in use in th
6. another type of interfering signal Ground Balancing is the process by which the metal detector cancels the unwanted ground signals while leaving signals from buried metal objects intact This is accomplished by establishing the detector s internal Ground Balance setting this setting is calibrated to the soil and eliminates the signal produced by ground minerals Calibration to the actual soil condition will result in deeper target detection quieter operation and more accurate target identification This calibration or Ground Balancing can be accomplished automatically with the detector s internal computer by pushing the Trigger Switch forward or manually in the All Metal menu The ground balance setting carries through into all operating modes In Discrimination mode the ground signal is generally inaudible unless the discrimination setting is 0 AUTOMATIC GROUND BALANCING PROCEDURE FASTGRAB 1 Find a spot of ground where there is no metal present 2 Hold the detector with the searchcoil about one foot above the ground 3 Push the TRIGGER SWITCH forward with your index finger 4 Physically pump the searchcoil and detector up and down over the ground Lift it about 6 inches above the ground and lower it to within 1 inch of the ground about once or twice a second 5 A 2 digit value will appear on the display This is the Ground Balance setting If the detector s internal computer is unable to ground
7. are mixed together without categorization Detecting Activities continued Relic Hunting continued or documentation their context will be lost The ground balancing and Fe O 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 This information in turn helps to reveal the history of the site To find promising sites to hunt conduct research at your local library look for clues in old newspapers and seek information on the internet Where did buildings used to be Which have since been torn down Where did people gather for public events like dances and county fairs Where did train and stage lines run Where were the swimming holes In almost every town there is a historical society and museum of local history Most museums are grateful for anything they can put on display and when you dig something you cannot identify the curator can often identify it for you If you work closely with the local historical society or museum landowners will be more willing to grant you permission to search their property Some of the most promising sites for relic hunting are places being cleared for development After the site is built on whatever is in the ground will become inaccessible The property owner can often be persuaded that the site should be searched immediately while it is still searchable Gold Prospecting In the United Sta
8. bar graph indicates higher amounts of iron mineralization Gold prospectors are mostly a friendly bunch and willing to spend some time showing a beginner how to increase his odds of finding the yellow stuff Many will invite you to search on their claims if they have any once they get to know you In some gold areas a lot of the terrain is under claim so you need to learn how to recognize posted claims and stay off of them unless you have the claim owner s permission Prospecting clubs such as the GPAA often own claims which are open to their members and sponsor group outings to good gold areas It s a thrilling experience to dig into the ground and pull out a precious piece of yellow metal that you are the first person on earth to see If you love being outdoors have patience and can stay motivated by the prospect of finding that next nugget then beeping for gold may be the hobby for you While only a few get rich prospecting if you are not among them think of it as outdoor recreation where your finds defray the expense of having fun 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 This means doing research Some caches have been the subject of many stories you c
9. beaches ground balancing must be done manually DISCRIMINATION Discrimination refers to a metal detector s ability to ignore metal objects in selected categories especially iron and aluminum This makes searching much more pleasant in an area with a lot of metal trash The F75 offers a wide variety of discrimination features which you can select according to the search conditions and your personal preference DEPTH READING The estimated Depth Reading displayed when pulling the PinPoint toggle is based on the strength of the signal It is calibrated to coin sized objects Smaller objects will read deeper than they actually are and large objects will read shallower than they actually are AIR TESTING There may be times when you want to test or demonstrate the metal detector without sweeping it over the ground for instance if not fully assembled or if you are indoors To air test place the searchcoil in a spot where the detector is stable and more than two feet away from any large masses of metal including the reinforcing steel usually present in concrete If you are wearing a wristwatch or jewelry on your hand or arm remove it Then test or demonstrate by waving metal objects over the searchcoil wave objects briskly several inches over the top of and parallel to the searchcoil Ground balancing cannot be tested or demonstrated in air unless you happen to have appropriate specimens of iron minerals available SWEEP SPEED The F75
10. location of buried metal objects Audio signal indicator and vibrator Runs on 1 9 Volt Battery FPOINT Metal Sand Scoop Large galvanized metal scoop with filtering holes Strong Rubberized grip SAND SCOOP Lesche Knife Made from high quality heat treated tempered steel The ultimate digging tool Comes with a durable sheath 12 in length with a 7 serrated blade LESCHE KNIFE Fisher Apron Natural canvas with 2 large pockets FISHER APRON Fisher T Shirt 100 cotton with 1 Fisher Logo Sizes LG XL amp XXL Fisher Baseball Cap One size fits all Replacement Accessory Search Coils 11 Biaxial Standard Coil replacement 11COIL F75 10 Concentric Accessory Coil 10COIL F70 6 5 Concentric Accessory Coil 6COIL E 5 Biaxial Accessory Coil 5SCOIL F75 Coil Covers Specially made to protect your coil from abrasion and damage 11 Biaxial Standard Coil Cover COVER 11DD 10 Concentric Accessory Coil Cover F70COVER 6 5 Concentric Accessory Coil Cover 6COVER E 5 Biaxial Accessory Coil Cover SCOVER CZ3 Gold i Gold Kit Deluxe Kit Hardrock Kit Prospecting Kits ft ass Items Included 10 Gold Pan x x x 14 Gold Pan x x x Classifier x x 2 Shatterproof Vials x x x Snuffer Bottle x x x Black Sand Magnet x x Treasure Scoop x x Tweezers x Magnifier x Crevice Tool x Rock Pick x Instruction Booklet x x x Backpack x x M
11. near the center of the response pattern but not at the exact center release the trigger and then pull it again Now you will only hear a response when the searchcoil is right over the top of the target Repeat this procedure to narrow the zone even further Each time you repeat the procedure the field of detection will narrow further Buy a Pinpointer When you kneel down to unearth the desired object you may find it frustrating as the object may appear exactly like the surrounding soil You may hold the object in your hand and find it necessary to pass a handful of dirt over the searchcoil to see if it contains metal An easier way is to use a handheld pinpointer It is a probe like device which is poked into the ground making close up pinpointing a snap reducing digging time and minimizing the size of the holes you will dig Fisher Research Labs offers the FPoint pinpointer a robust and inexpensive device designed for this purpose 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 At the top of the display a block illuminates to indicate the classification of the object Target ID is provided in all three mo
12. new to the F75 toggling back to default process from bP or CL can serve as a learning tool to understand the different response characteristics of the different processes 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 But you do not want to hear the ground you just want to hear the target So always Ground Balance first After you have discovered a buried metal target using the ALL METAL or DISCRIMINATION Modes use the trigger switch to pinpoint its exact location Search Techniques continued Position the searchcoil an inch or two 2 5 5cm above the ground and to the side of the target Then pull the trigger Now move the searchcoil slowly across the target and the sound will indicate the target s location As you sweep from side to side and hear no sound at the ends of the sweep the target is located in the middle of that zone where the sound is loudest and the audio pitch is highest If the sound is loud over a wide area the buried object is large Use the PinPoint feature to trace an outline of such large objects 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 siz
13. the function you want The word SETTING will pop up in the middle of the display and the present setting of that function will be displayed as a number To change a setting rotate the knob To increase a value rotate to the right clockwise To decrease a value rotate to the left counterclockwise If you select a function and do not make a change to that function after 7 seconds the detector will exit the menu system automatically deactivate the SETTINGS knob and resume normal operation FISHER LABS EE EE GE IRON FOIL NICKEL TAB ZINC DIME QTR If you press the MENU button while the machine is Fe 0 BATT DISCRIM ALL METAL TARGET I D i P Sensitivity E Stat Motion In normal operation the Disc Level M Mi Threshold user interface will return to Notch W G B PHASE E Audio Pitch Of Tones W OVERLOAD RAISE COIL Ml Sensitivity the last menu feature E Manual G B setting This feature allows you to have quick access to a function that you want to adjust frequently SETTINGS Greund 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
14. the surface This effect may be observed in either fresh or saltwater Saltwater Hunting Saltwater is highly conductive and produces a strong signal which is like that of metal The F75 is not specifically designed for high performance in saltwater but can be used in this environment If you desire to search in or over saltwater the following measures will usually be sufficient to silence the saltwater response while retaining acceptable sensitivity 1 Set the sensitivity in both modes to less than 30 2 Ground balance the machine manually in Motion All Metal mode 3 Search in the Discrimination mode with a discrimination setting higher than 25 How Metal Detectors Werk Most hobby metal detectors use VLF Induction Balance technology Here s how they work The searchcoil also called search head or loop contains two electrical induction coils which are like antennas One coil transmits a rapidly alternating magnetic field illuminating the region surrounding the searchcoil If metal is present its electrical conductivity distorts the magnetic field If iron metal is present its magnetism also distorts the magnetic field but in a different way allowing the metal detector to distinguish between ferrous and nonferrous metals The other coil is a receiving antenna which detects changes in the magnetic field caused by the presence of metal Electronic circuits amplify this weak signal analyze it to determine the changes whic
15. to 29 you may notice that the background noise increases Despite this increase as you decrease sensitivity to the lower setting 29 the sensitivity is in fact lower under 30 and the machine is less susceptible to overload from large targets ground minerals and saltwater You may need to adjust to a setting of 29 or less to silence electrical interference or to prevent overload on highly mineralized ground or in saltwater You may also notice a shift in the ground balance setting over difficult ground conditions as you cross this transition MANUAL GROUND BALANCE Manual Ground Balance can only be performed while in an All Metal mode but the resultant setting will carry over if you change into Discrimination mode See the previous section on Ground Balancing for instructions on how to use this feature We suggest that you manually ground balance using only the MOTION All Metal Mode The result will be more accurate than when using STAT 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 similar to PinPoint but occupies a different position on the user interface The audio signal gets stronger as the searchcoil approaches the ground Unlike the other modes the detection sound will not disappear if you stop moving the searchcoil The four adjustments are performed the same as with MOTION All Metal Mode as described on the prece
16. urine from livestock Unless dry cow pies can sound off like they are metal Ocean beaches have saltwater that subject is discussed toward the end of the manual In spots where there has been intense fire such as a campfire site or where a stump was burned during land clearing the soil minerals may be altered by oxidation so that their ground balance setting is lower than that of the surrounding soil In such cases search slowly and change the G B setting as frequently as necessary In some areas electrically conductive industrial minerals such as fuel coke slag clinkers left over from burning mineral fuels or charcoal have been dumped or used as landfill Individual lumps of these materials can usually be quieted by reducing sensitivity and searching with a discrimination level of at least 25 However where the ground consists primarily of such materials you may not be able to search quietly In that case do not dig unless a signal is crisp and repeatable Electrically conductive natural minerals such as graphite graphitic slate or sulfide ore minerals are rarely encountered except when gold prospecting When gold prospecting you need to be able to hear everything and you can expect to dig conductive minerals that turn out not to be gold In a given locality you may learn to recognize what type of rocks these minerals are found in and to ignore them if people in the area say that gold is not found in rocks of that type S
17. you flatten it the response will be crisper and more like that of a coin Again these differences are most readily noticed in the All Metal modes Long skinny iron or steel objects such as nails usually produce a double response when scanned lengthwise and a weaker single response when scanned crossways This is most noticeable in the Motion All Metal mode However a coin lying on its edge can produce a similar response so rely on both the target ID as well as target feel to distinguish between different kinds of objects Objects within 2 to 3 inches of the searchcoil will often produce multiple responses as you sweep across them because the response field close to the searchcoil is irregular Search Techniques continued Estimating Target I D With a single sweep over a target you will usually see a 2 digit target ID displayed on the LCD Repeated sweeps back and forth over the target may cause the 2 digit target ID values to change with each sweep of the coil this may seem inconsistent with your discrimination setting These variations and inconsistencies provide important clues regarding the identity of the buried object Most metal detectors have difficulty properly identifying steel bottle caps and the F75 is no exception Steel bottle caps will often read in the coin range at the high end of the scale The ID number you receive from a buried coin will usually be consistent regardless of sweep speed or angle The readings from a s
18. 75MBLK Rev 2 122211
19. F THE TARGET OR SWEEP RAPIDLY a lf the ID is repeatable in the range of 68 to 72 when passing the center of the searchcoil over the target at a normal speed then the target is probably a dime or copper penny b If the ID is not in the range of 68 to 72 then i Sweep the back end of the searchcoil over the target If tones change from high to low the target is probably a bottle cap ii Sweep the center of the searchcoil rapidly across the target 1 If tone and ID drop it is probably a bottle cap 2 If a bottle cap then the faster you sweep the lower the tone Sweep back end of searchcoil over suspected bottle cap Low Tone Bottle Cap 5 USE THE CONFIDENCE INDICATOR Coins will usually produce a high confidence level whereas steel bottle caps and other trash will usually indicate a low or erratic confidence even if the ID numbers are consistently in the range of coin Confidence level is useful even if not using the dP or 3b processes Search Techniques Sweeping Searchcoil this does not apply to Pinpointing with the trigger switch Keep the searchcoil in motion to detect targets Sweep the searchcoil parallel to the ground do not lift the searchcoil at the end of the sweep When you have located a target and continue sweeping back and forth for verification use broad deliberate sweeps across the target for the most accurate target ID Do not use short sweeps as you migh
20. FISHER 2 SPECIAL EDITION 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 Intuitive menu driven user interface Large LCD screen e Visual indicators of important values such as Target Identification Target Confidence Target Depth both running depth and pinpoint depth Ground Mineralization e Multiple Search Modes Discrimination Static All Metal Motion All Metal Trigger actuated FASTGRAB ground balancing with manual override e Waterproof 11 inch open frame BiAxial searchcoil Housing constructed of a carbon fiber polycarbonate blend Trigger actuated target pinpointing with variable audio pitch Fully Adjustable Arm Rest e Display backlight for night and low light conditions e Notch and discrimination controls e Covers provided for both the control housing and battery box Made in the USA If you have any questions or need assistance with your metal detector Call 1 915 225 0333 and ask for Fisher Hobby Technical Service Table Of Contents Specifications ee eke Sota 4 Quick Start ccc hed oh eee ba ee eee ep ee ee 5 Mechanicals Assembly Instructions 6 7 Mechanicals Pa
21. H feature To use DISC LEVEL 1 Highlight DISC LEVEL using the MENU button 2 Rotate the SETTINGS knob As you rotate the knob a number between 0 and 65 appears 3 Press MENU when you reach the desired target discrimination value e If you do not press MENU and let the display time out the last displayed value will be stored as the discrimination value All targets up to and including the value selected will be eliminated from detection unless notched in 5 A slash will appear over the target words being eliminated Notice that two slashes can appear over each word The left slash represents the bottom half of the range the right slash represents the top half of the range When you select a value within any range the slash will appear even though all values within that range might not be eliminated from detection To recall the discrimination setting press the MENU button until you enter the DISC LEVEL feature vm Discrimination Mede 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 1 Reset all detector values to default a turn detector off b press and hold red MENU button and push forward and h
22. ams and clays will tend to read in the 50 80 range and red clays will tend to read in the 35 55 range To express it in other terms the more highly weathered oxidized or finely grained the soil is the lower the numeric reading will be The bar graph indicates how much iron mineralization is present For it to work the searchcoil must remain in motion The most accurate readings will be achieved by pumping the coil as you do when ground balancing The higher the mineralization the greater the necessity to ground balance the detector for the best depth performance If you are searching for relics you can make a map of the soil of the site Make a grid of the site Then collect data Ground Balance to document mineral type view mineral amount on the Fe O bar graph Then plot the data on the site map and draw isolines In this way you may be able to locate areas which have been dug backfilled or subjected to fire This information in turn helps to reveal the history of the site 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 Sometimes there is jewelry present You will usually search using discrimination to get rid of the iron and the aluminum tr
23. an read about in print but you need to be able to sort fact from fiction If you can get copies of old newspaper stories about the circumstances surrounding the hiding of the cache you may find discrepancies which help you to judge the reliability of the information available Often the best information on an old cache is to be learned from old timers who live in the area where the cache is thought to be In the case of newer caches often the only information is what can be obtained from family and acquaintances of the person who is believed to have hidden the cache The ownership of a cache is not always clear Sometimes it belongs to the person or heirs of the person who hid it sometimes it belongs to the owner of the property on which it is located and sometimes it belongs to the person who finds it or some combination of the above If the contents of the cache were stolen this fact can also complicate the question of ownership Find out what laws apply to the cache in question and always make sure that the issue of ownership is resolved prior to recovering a cache Compared to a coin a cache is usually large and deep Searching in Motion All Metal mode is recommended However for a really deep cache it may be advantageous to search in STAT mode frequently pulling the trigger momentarily to maximize sensitivity Shallow Water Hunting All Fisher Research Labs searchcoils are waterproof allowing you to search in shallow wa
24. ance to the target but response is noticeably slower In the Boost and Cache Locating processes if you sweep fast with the searchcoil close to the ground you will lose some target separation This loss is most noticeable using the Cache Locating process Target separation in these processes is comparable to that of the default process provided that you slow down your sweep Some users when fatigued after hours of searching get sloppy with their sweep technique The Boost process is more tolerant of sloppy sweep technique than are the other processes and may be preferred at these times Search Techniques continued The F75 s other processes have a reputation for lightning fast response over targets with the result that the duration of the sound over a good target can be very short especially in a trashy area The Boost process lengthens the duration of the target s sound Many users will find this audio feedback less fatiguing the Boost process makes it easier to listen through the trash clutter to hear good targets Whereas in Default process slowing your sweep speed leads to a loss of sensitivity the Boost and Cache Locating processes allow you to sweep slower without a loss of sensitivity The Cache Locating process is primarily for locating large deep objects while searching with the searchcoil several inches off the surface of the ground It is free of the gradual threshold drift which can occur in the Static All Metals Mode In
25. ash even though this mode will cause you to miss some of the jewelry Much coinshooting is done in lawn areas where digging holes would cause damage to the grass We recommend use of an accessory hand held pinpointer in such cases Recovering targets is usually done by first accurately pinpointing the target then carefully cutting a slit in the turf with a knife and tamping it firmly when you are finished In these situations you cannot recover deep targets for fear of damaging the turf so you can cut down on nuisance signals by reducing the sensitivity When searching on private property first get the permission of the property owner Most of the public places where one is likely to do coinshooting are city county or school district property There is usually no ordinance prohibiting use of a metal detector as long as you are not causing damage Sometimes such ordinances do exist Administrators and security personnel often have the legal authority to prohibit any activity they do not like even if there is no ordinance against it If there is a metal detecting club in your area someone will usually know what areas can and cannot be searched If you are ever in doubt about hunting an area then ask before hunting Be prepared to always put your best foot forward when using a metal detector in a public place Pick up any trash you recover put it in a pouch or pocketed apron This way you can explain that you are performing a public ser
26. atteries may not work especially in cold weather Do not use these batteries Expect 40 hours of service in the field with one set of alkaline batteries Rechargeable batteries will usually deliver over 25 hours of service without recharging but when they start running low they die suddenly with little warning Always install batteries which are of the same type and the same state of charge Otherwise battery life will be determined by the weakest battery because the good batteries cannot deliver their power with a dead battery blocking the current All 4 batteries are installed with the positive terminals facing upward The LCD screen shows battery condition on the right IMPORTANT To avoid stressing the battery spring connection install the batteries using this technique 1 Position the bottom negative side of the battery on top of the spring 2 Do not install the top of the battery into the compartment yet 3 Push down on the battery to compress the spring 4 With the spring compressed a bit then tip the battery upright and push back into the compartment RIGHT WAY WRONG WAY Mechanicals continued ARM REST The arm rest WIDTH and POSITION are both adjustable Arm Rest Width The sides of the arm rest can be bent inward and outward To best stabilize the detector to your arm and body movement squeeze the sides of the arm rest around your forearm For a very secure fit some users prefer to bend the arm res
27. balance an error message will appear If the message OVERLOAD RAISE COIL CAN T GB appears you will also hear a siren sound You are probably over metal If the message CAN T GB appears you may not be pumping the coil or you may be over a small piece of metal Note FASTGRAB will not automatically balance over highly conductive soils such as a wet saltwater beach Ground Balancing continued MANUAL GROUND BALANCING In most situations it is preferable to push the trigger switch to activate FASTGRAB automatic ground balancing Generally it is best to first let the computer automatically cancel interference from ground minerals However for gold prospecting searching on a wet saltwater beach or searching in an area with so much metal trash that there is no clean ground for the computer to sample we recommended that you manually ground balance Manual ground balancing requires a bit of skill acquired with some practice The range of ground balance settings indicated on the display range from 0 to 99 however each displayed number spans 5 detent steps on the settings knob The actual internal ground balance settings change with each step there are a total of 500 different settings Under some ground conditions you may be able to hear the individual steps in the setting The bar graph on the LCD display indicates the amount of magnetic mineralization The searchcoil must be in motion to measure T
28. chart above are eliminated from detection When you enter the program to make change to the notch settings you are Boe TE ELELS om IRON FOIL NICKEL TAB ZINC DIME QTR changing the status of the notch If slash is illuminated and you press MENU to set a notch range you will be notching out this range If a slash was previously illuminated and you press MENU to set this notch range you will be notching in this range Programming a notch range always AN reverses the status of the notch Discrimination Mede continued Using DISC LEVEL in conjunction with NOTCH gives you a great deal of flexibility in deciding which values to include or exclude from detection Beware that this combination can be confusing Here are some examples of NOTCH used in conjunction with DISC LEVEL If Discrimination Level is set at 60 and you set the top of foil 21 25 notch between 21 and 25 then top of foil range 21 25 is NOTCHED IN i e detected If Discrimination Level is set at 23 and you set the top of foil 21 25 notch between 21 and 25 then 21 22 amp 23 are NOTCHED IN 24 amp 25 are NOTCHED OUT If Discrimination Level is set at 15 and you set the top of foil 21 25 notch between 21 and 25 then 21 25 are NOTCHED OUT 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 wi
29. concentration of them the discriminator may not quiet them all In that case you can revert to the rule of thumb 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 In the event of detection of electrical interference from electrical power lines electrical or electronic appliances or another metal detector it is usually necessary to reduce the Sensitivity setting to achieve quiet operation Alternatively use the Frequency Shift feature described earlier in this manual If while searching you are constantly getting signals from which you cannot recover metal targets you may be detecting small or deep targets which are not recoverable using the methods at hand So you may do better if you reduce the Sensitivity setting Search Techniques continued Tips on ground balancing 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 If you switch to All Metal mode ground balancing will probably be necessary You must find a spot of ground which is free of metal to accurately balance to the ground Before you attempt to Ground Balance sweep back and fo
30. croprocessor then displays a rectangle like icon along the top of the LCD screen above the corresponding category For instance if the detected signal fits within the parameters usually exhibited by zinc pennies the microcomputer will categorize the signal as zinc penny The LCD screen will then illuminate the block above ZINC Copper pennies pre 1982 will usually register in the DIME zone Most gold jewelry is small and will tend to read in the 16 55 range Silver jewelry usually has more metal in it and therefore tends to produce higher readings 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 DEPTH When the trigger is pulled to facilitate pinpointing an object the 2 digit numerical display indicates the approximate depth of the object in inches based on the assumption that the object is a typical U S coin Small objects will read deeper than they actually are and large objects will usually read shallower than they actually are The DEPTH bar graph on the left of the display divides target depth into shallow medium and deep This depth range appears while searching and is less accurate than the value derived using the pin
31. d 3 Turn the SETTINGS KNOB to adjust the setting The goal is to eliminate the sound as the coil is being pumped over the ground In some soils the sound is not completely eliminated If the ground balance adjustment is incorrect there will be a difference in the sound as the searchcoil is either moving toward or away from the ground It sounds like you are either pulling the sound out of the ground or pushing the sound into the ground If the sound is louder as you raise the searchcoil increase the ground balance setting If the sound is louder as you lower the searchcoil reduce the ground balance setting NOTE Experienced users often prefer to adjust the ground balance to get a weak but audible response when lowering the searchcoil This is called adjusting for positive response 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 setting is too high a number the response of minerals will be positive This means that when the searchcoil is lowered to the ground in PinPoint Stat or Motion All Metals mode the sound will get louder as the searchcoil approaches the ground The sound will grow quieter as the searchcoil is raised What if anything you will hear in discrimination mode
32. des and requires motion in all modes including STAT NUMERIC TARGET I D 2 digits The following table shows the numbers typically associated with certain commonly encountered nonferrous metal objects Older silver U S coins usually read about the same as their modern clad equivalents Modern quarter sized dollar coins like the Susan B Anthony and the Sacagawea read about the same as a quarter Many Canadian coins are minted from a magnetic nickel alloy which gives very inconsistent readings and may register as iron Most one ounce silver bullion coins will fall into the same range as the modern U S 1 Eagle OBJECT TARGET I D Most iron objects 4 12 foil from gum wrapper 16 25 U S nickel 5 coin typically 30 aluminum pull tab 33 55 TRON FOIL NICKEL TAB ZNC DME ome aluminum screwcap 60 70 7 zinc penny dated after 1982 typically 60 aluminum soda pop most often 63 69 a 2 but can vary widely copper penny clad dime typically 70 U S quarter 25 coin clad typically 80 50 coin modern clad typically 86 old silver dollar coin typically 90 US silver Eagle 1 coin typically 91 PROBABLE TARGET I D The probable target ID zones at the top of the LCD display represent the signal ranges produced by various coins and types of metal objects When a metal target is detected the microcomputer analyzes the signal and categorizes it based on what kinds of metal objects usually produce that kind of signal The mi
33. difficult ground conditions as you cross this transition GROUND BALANCE Always perform the ground balance procedure before searching in STAT mode using the trigger or with the manual adjustment If you do not ground balance before searching in STAT mode most ground will produce an audible tone as you lower the searchcoil the ground will sound off Some soils will not sound off but will remain quiet with a loss of sensitivity DEPTH DISPLAY To see target s depth in inches pull the toggle switch TARGET ID Move coil back and forth over target to see visual target ID 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 The F75 discrimination system is much improved over conventional discrimination systems and may function quite differently than other discriminators you may be accustomed to In older systems the apparent sensitivity decreases as discrimination level increases The F75 s sensitivity may increase as discrimination increases depending on the process number and notches being used Therefore do not use the discriminator to control sensitivity First set the discrimination level and notches to establish objects to detect or eliminate then adjust sensitivity downward to eliminate interference or upward
34. ding page THRESHOLD The audio threshold in the STATIC mode is internally fixed and cannot be adjusted by the user Retuning The audio threshold will slowly drift when searching in this mode If you move quickly between temperature environments such as from shade to sun audio threshold may drift more rapidly until the searchcoil temperature stabilizes When the audio threshold drifts in this fashion pull the trigger back momentarily to retune the detector You will need to retune periodically when searching in this mode AUDIO PITCH Works the same as in MOTION mode see previous page SENSITIVITY Set the sensitivity high enough too hear some random background noise and or a slight amount of ground response If you do not hear these noises you will sacrifice detection depth If the background chatter is too annoying or the ground noise is so high that it impedes operation reduce sensitivity Such a downward adjustment in sensitivity improves depth detection as you can now hear weak signals better The sensitivity system has two stages 1 29 low gain and 30 99 high gain As you lower sensitivity and cross the transition from 30 to 29 in STATIC mode it may be necessary to retune by pulling the trigger switch momentarily You may need to adjust to a setting of 29 or less to silence electrical interference or to prevent overload on highly mineralized ground or in saltwater You may also notice a shift in the ground balance setting over
35. e tones and broken sounds There may be a slight reduction in the ability to separate adjacent targets Use this process in areas with a high concentration of steel bottle caps Also refer to the Capabilities amp Limitations section for sweep techniques to aid in the identification of steel bottle caps for use in plowed fields Some users may prefer this process for hunting in irregular ground especially plowed fields BOOST PROCESS This process is an enhanced sensitivity version of the dE default process It is particularly useful when searching for deep targets in a non trashy area or on a site where vegetation makes it necessary to raise the searchcoil several inches above the surface of the ground It will also produce excellent results on trashy sites provided that you slow down your sweep speed sweep the coil slower than you would when using the Default process When the Boost process is selected the response characteristics of the Motion All Metal Mode are also modified these characteristics include less noise and a slower response speed Discrimination Mede continued CL CACHE LOCATING PROCESS This process is an enhanced sensitivity slow speed version of the dE default process Its primary use is in locating large deep objects while sweeping the searchcoil several inches above the surface of the ground under these conditions it goes deeper than the other processes When the cache locating process is selected the response
36. e connection to housing Use minimal finger pressure to start thread Do not force threads Nut may not completely cover all threads when fully engaged 9 Adjust to your height Hold detector standing up with your arm in the armrest Place searchcoil flat on the ground with back edge of coil 6 in front of your toes Click pin on lower rod into nearest hole Firmly tighten bottom locking collar to secure lower stem 10 Attach cable to top of rod with upper Velcro strip 11 Tighten up coil knob to keep searchcoil from flopping 12 Insert batteries 4 batteries are all installed the same way positive terminals pointed upward After establishing a comfortable length firmly tighten the locking collars on the rods to prevent the tubes from rattling Rotate the collars a full 270 to engage and lock in place If you are unable to rotate a full 270 use gloves for a better grip If the searchcoil appears crooked with respect to the pole loosen both locking collars and re adjust Hold each of the lower poles in the counterclockwise position as you tighten the locking collars Mechanicals BATTERIES not included The F75 requires four AA batteries These non rechargeable chemistries may be used Alkaline Nickel Oxy Hydroxide Panasonic Oxyride or Duracel PowerPix and lithium iron disulfide Energizer L91 Nickel metal hydride and nickel cadmium rechargeable chemistries may also be used Zinc carbon and so called heavy duty b
37. e field To eliminate the weakest signals adjust into the negative region which will allow the machine to run silently if the Sensitivity is not set too high The threshold level changes slightly with each detent step on the SETTINGS knob Each number on the numeric readout corresponds to five steps AUDIO PITCH This control allows you to change the range of frequencies that you hear Values range from 9 to 9 0 is default Negative numbers lower the frequency of the tone you hear positive numbers raise the frequency This feature is intended to make the tone more pleasant to your ear choose your personal preference Users who have suffered some hearing loss including the natural loss of ability to detect high and low frequencies with age may find this control helpful SENSITIVITY This controls the signal gain and is adjustable from 1 to 99 In the presence of electrical interference high ground mineralization or variable ground mineralization operation will usually be too noisy wobbly and erratic sound if the sensitivity is set too high At settings above 90 the internal circuit noise of the machine will probably be audible The sensitivity level setting is largely a matter of personal preference However if you cannot hear at least some noise the smallest or deepest objects will not be detected The sensitivity system has two stages 1 29 low gain and 30 99 high gain As you decrease sensitivity and cross the transition from 30
38. e is this if you are digging tiny pieces of trash metal then if gold were present you would have found small gold pieces too Because most gold nuggets are tiny and are usually found in soil which is high in iron oxide Detecting Activities continued Gold Prospecting continued minerals serious gold prospecting requires a detector with high sensitivity and true ground balanced motion all metal operation Run the machine with the sensitivity high enough to hear some noise from ground minerals and learn the language of the sounds you hear Headphones are recommended unless consideration for safety for instance rattlesnakes rules them out Move the searchcoil slowly and deliberately carefully controlling its height above the ground to minimize noise from iron minerals in the soil If you hear ground noise your Ground Setting could be a bit off so perform the ground balancing procedure again As you walk even a very short distance ground conditions can change The ground geology typically associated with gold will tend to change over very short distances Fe O bar graph indicates the amount of iron mineralization in the soil In most gold fields especially alluvial placer deposits gold tends to be S associated with iron minerals especially magnetite black sand If you know this to be the case in the area you re working you can maximize your gold recovery by concentrating your effort on areas where the
39. e signal level currently preset If the searchoil is up in the air away from metal this maneuver corrects for threshold drift due to temperature changes When the trigger is pushed forward FASTGRAB automatic ground balancing is activated The internal computer measures the magnetic properties of the soil in order to cancel interference from naturally occurring minerals in the ground After the detector measures the soil in this manner the detector then uses this information to control operation in both the All Metal and Discrimination search modes FASTGRAB can be used at any time during operation 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 mode and Discrimination mode the top line of the menu system must be highlighted Press the MENU button until the top line of the menu is highlighted When either All Metal or Discrimination is highlighted rotate the SETTINGS knob to move between the two categories Each search mode has several adjustable function settings ALL METAL Threshold not adjustable in stat mode Audio Pitch Sensitivity and Manual Ground Balance DISCRIMINATION Sensitivity Discrimination Level Notch Number of Tones and Process Number To select a function push the MENU button and continue pushing in order to move to
40. earch Techniques continued HOT ROCKS A hot rock is a rock which causes the metal detector to sound off because the rock contains iron minerals They come in two basic types Negative hot rocks also called cold rocks are usually magnetite or contain magnetite and give a negative response because their ground balance value is a higher number than the soil they are found in They tend to be dark in color usually black and usually heavy In some cases they will have rust stains They are usually attracted to a magnet and for this reason gold prospectors always carry a magnet the ultimate ferrous nonferrous discriminator In Motion All Metal mode negative hot rocks produce a boing sound rather than the zip sound of a metallic target recognize the difference and you will learn to ignore them Positive hot rocks are iron bearing rocks which have been oxidized by natural weathering processes so that their Ground Balance number is a number lower than the soil they are found in They are often small right on the surface sound just like a gold nugget and are common in many gold prospecting areas They are usually but not always drawn to a magnet They are most often reddish in color but are often black brown or yellow On relic hunting sites red clay bricks and rocks which have lined a fireplace or a campfire will often be hot rocks The discriminator will usually eliminate them without difficulty if widely scattered but if there is a large
41. early particularly if searching in a noisy location For safety reasons do not use headphones near traffic or where other dangers like rattlesnakes are present This device is to be used with interconnecting cables headphone cables shorter than three meters Intreduction to the Fisher F 75 HIGH PERFORMANCE The F75 is a multi purpose high performance computerized metal detector It has the high sensitivity and ground balancing control needed for professional gold prospecting the discrimination responsiveness needed for serious relic hunting under difficult conditions and visual target 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 USER COMFORT The F75 is among the lightest and best balanced of all high performance metal detectors so you can hold and swing it almost effortlessly The arm rest position is adjustable to fit your arm The grip is durable high friction foam elastomer comfortable in any kind of weather The controls are conveniently located and easy to learn how to use Locking collars on the tubes eliminate rattling EASY TO USE amp INFORMATIVE INTERFACE The entire menu is always visible on the LCD display The LCD display indicates the electrical signature target I D of the detected metal object The display provides c
42. ed target But what if it is not a coin sized target The most common example is that of an aluminum can Flattened aluminum cans are usually identified as quarters Their large size will produce a strong signal tricking the microcomputer into thinking that it is a shallow coin The following explains techniques for differentiating buried aluminum cans from coins Sweep back and forth to get a feel for the target keeping the searchcoil close to the ground Now continue to sweep back and forth as you slowly raise the searchcoil higher and higher If the response diminishes quickly and never gets very broad the target is probably a coin If the response diminishes slowly as you lift the searchcoil and you get a broad response the target is probably an aluminum can If you practice this by laying a coin and a flattened aluminum can on the ground you will quickly understand how to differentiate the two and you will probably never have to dig another aluminum can And you will know whether it was deep or shallow This technique works well in the All Metal modes and to a lesser extent in Discrimination mode Objects which are ring shaped or flat and round like coins tend to give a narrower crisper response than objects of similar size with irregular shapes The easiest way to demonstrate this is with an aluminum screwcap from a soda bottle In its normal shape it occupies a volume and gives a somewhat broader response than that of a coin But if
43. from the property owner If you intend to hunt on public land check first with the administrator to make sure it s not illegal Certain kinds of sites on both public and private land are protected by law from relic hunting If there is a metal detecting club in your area some of the members will probably know what the laws are in that area and which sites are and are not off limits Relic hunting is most rewarding if you have an avid interest in history In many cases the value of a relic is not the object itself but the story it s a part of what historians call context and archeologists call provenance A few pieces of rusty metal can tell the story of life in a specific place or that of a specific family or person from hundreds of years ago They can capture our imagination and help to give context to our lives today The value and context of a find can be readily lost without proper documentation and storage Add finds to your collection with care Take the trouble to understand the site you are searching and keep track of where you find things Describe exactly how and where items where found Consider including a sketch of the site with your finds Organization techniques might include storing together all finds from the same site Alternatively if you have an interest in specific items like buttons make a button collection and within that collection document the circumstances surrounding each button found If your finds
44. general its response is too slow for ordinary relic hunting or coinshooting But if you prefer a very slow sweep speed for instance if you are accustomed to using the older technology of heavy and sluggish competitive detectors you can still achieve good results In areas which have been pounded to death and were seemingly hunted out even by the predecessor version of the Fisher F75 the Boost process can make such sites productive again By detecting targets which were just out of reach of other machines or by lengthening the duration of good sounds that were too hard to hear amid trash sounds old sites are again productive If a site has been especially productive in the past you may want to revisit it using the Cache Locating process and utilize a very slow sweep Most of the foregoing techniques apply both to the Discrimination Mode where the process is selected and to the corresponding Motion All Metals Mode whose response characteristics are also modified when the Boost and Cache Locating processes are selected While searching in bP or CL process you may also want to periodically toggle back to dE process Press and Hold the MENU button to temporarily engage the dE process For users familiar with the F75 default process this can serve as a target check Under some conditions the default process may identify targets more accurately Targets yielding a marginal response in one process may sound different in another process If you are
45. h occur as the searchcoil sweeps over the target and then convey the information to the user in the form of a visual display or audio tones Most modern metal detectors perform many of these tasks in software running on an internal microcomputer The iron minerals which are present in most soils also distort the magnetic field obscuring the weak signals of small or deep objects This can cause the object to go undetected or to be misidentified when it is detected Much of the technology that goes into modern metal detectors is devoted to the task of eliminating the unwanted signals from iron minerals in the soil while not losing the signals from metal objects This device has been designed to operate with the antennas listed below and having a maximum gain of 3 dB Antennas not included in this list or having a gain greater than 3 dB are strictly prohibited for use with this device The required antenna impedance is 53 ohms 10COIL F70 11COIL F75 5COIL F75 6COIL E The following statement is not relevant to metal detectors but is printed here to satisfy legal notification requirement To reduce potential radio interference to other users the antenna type and its gain should be so chosen that the equivalent isotropically radiated power e i r p is not more than that permitted for successful communication The following countries allow free movement of this product within the European community FIN LVA SVN SUI BIH Treasure H
46. he most accurate measurement is obtained by pumping the searchcoil as in the Ground Balancing procedure The two digit G B Setting number displayed on the LCD indicates the type of ground mineralization Some typical ground mineralization types are 0 10 Wet salt and alkali 5 25 Metallic iron Very few soils in this range You are probably over metal 26 39 Very few soils in this range occasionally some saltwater beaches 40 75 Red yellow and brown iron bearing clay minerals 75 95 Magnetite and other black iron minerals When manually ground balancing try to feel out a spot on the ground to make sure there is no metal present In order to avoid locking onto metal the computer will not balance to ground where the GB setting is less than 40 Where the ground reads less than 40 manual ground balancing is required To perform the Manual Ground Balancing operation do the following 1 Select the MANUAL function The legend G B SETTING appears EA The present ground balance setting RONG FO NICKEL TANSENG DME QTR is displayed 0 99 The message PUMP COIL TO G B will appear 4887 ALLMETAL Sensitivity O Stat Motion 2 Physically pump the searchcoil and Be NG oe detector up and down over the votTones D ground SETTINGS Lift it about 6 inches above the AN ground and lower it to within 1 inch of the ground about once or twice a second Ground Balancing continue
47. hen operating in the bP or CL process The dE process will only be engaged while the button is depressed Releasing the button will return you to the process you were operating in When using any processes other than bP or CL pressing and holding the button will have no effect SETTINGS Knob On the left of the front panel Rotate the SETTINGS knob to 1 Change the setting or value of the highlighted menu selection you have chosen 2 Select the operating MODE when the top line of the menu is highlighted When used to switch back and forth between the DISCRIMINATION mode and ALL METAL modes the detector changes modes as soon as the corresponding selection is highlighted The All Metal modes are used to detect all metal objects including small or deep objects Use the Discrimination mode to ignore trash metal such as nails foil or pull tabs NOTE When the menu selection highlight disappears the SETTINGS knob is deactivated If settings values do not change when the SETTINGS knob is rotated press the MENU button to reactivate the user interface TRIGGER SWITCH Under the display in front of your hand While the trigger is pulled back metal objects are temporarily detected without the need for searchcoil motion This aids in pinpointing the exact location of objects which were found while searching in the Discrimination or motion All Metal modes When in static all metals mode pulling the trigger zeroes the audio threshold to th
48. horization RA Number Reference the RA number on your package and return the detector within 15 days of calling to Fisher Research Labs Inc 1465 H Henry Brennan Dr El Paso TX 79936 Phone 915 225 0333 ext 118 Fax 915 225 0336 Warranty coverage does not include the cost of transporting the detector back to an owner who is located outside of the United States of America NOTE TO CUSTOMERS OUTSIDE THE U S A This warranty may vary in other countries check with your distributor for details Warranty does not cover shipping costs According to FCC part 15 21 Changes or Modifications made to this device not expressly approved by the party responsible for compliance could void the users authority to operate this equipment FISHER Copyright 2011 by Fisher Research Labs Inc All rights reserved including the right to reproduce this book or parts thereof in any form Published by Fisher Research Labs Inc Fisher is a registered trademark of Fisher Research Labs Inc www fisherlab com 1465 H Henry Brennan Dr El Paso TX 79936 915 225 0333 ACCESSORIES Fisher Padded Carry Bag Rugged double stitched construction Includes handy exterior pocket for extra batteries or small accessories 103693000C Fisher Stereo Headphones Use with Fisher metal detectors Lightweight and adjustable with true stereo sound adjustable volume 1 8 jack with 1 4 adaptor 4 cable 9720950000 Fisher Pin Pointer Pinpoints the exact
49. ing in an area where there are many steel bottle caps or other flat iron trash targets minimize the amount of unnecessary digging with the following methods 1 SEARCH WITH THE be BOTTLE CAP PROCESS using the PROCESS feature This method calculates visual ID differently in order to cause steel bottle caps to read lower on the scale and to register less consistently A desirable object such as a coin will usually produce numeric values that are fairly consistent in both directions of sweep See PROCESS under the DISCRIMINATION Mode section of this manual 2 SEARCH WITH THE dP PROCESS This method calculates visual ID differently in order to cause steel bottle caps to ID lower on the scale and to register less consistently It also produces more audio clues to the character of the target 3 LIFT THE SEARCHCOIL Within 2 inches of a Bi Axial searchcoil the crossed magnetic fields of the Double D construction can produce anomalous responses If the object feels shallow strong signal narrow response or multiple responses in a single sweep and is giving consistent high readings like a coin raise the searchcoil 2 to 3 inches and try again coin will almost always continue to give consistent readings unless it is right next to an iron object A steel bottle cap that is at least 3 inches away from the searchcoil will usually produce readings that bounce around from medium to low numbers 4 SWEEP THE REAR OF THE SEARCHCOIL OVER THE CENTER O
50. is noted for its quick response This gives it unsurpassed ability to locate and identify good targets surrounded by trash It also permits the user to sweep the searchcoil quickly in order to cover more ground with very little risk of losing targets In general if you are searching an area where the desirable targets are more than 8 to 10 inches deep a faster sweep speed will detect to a greater depth and yield more accurate target IDs CHECKING A TARGET 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 If you check targets using sweep techniques learned on some other detectors you run the risk of getting less accurate target IDs You can use the confidence level indicator to improve your technique Capabilities And Limitations continued STEEL BOTTLE CAPS amp 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 If you are search
51. it necessary for the user to reduce the sensitivity setting Soils with large amounts of iron or salt minerals may also reduce detection depth or necessitate a reduction in the sensitivity setting TARGET IDENTIFICATION The F75 identifies the probable type of metal object by measuring its effective electrical conductivity which is displayed as a number from 0 to 99 on the LCD screen The effective electrical conductivity of an object depends on its metallic composition size shape and orientation relative to the searchcoil Since coins are minted to tightly controlled specifications they can be accurately identified Identification of pull tabs and foil is less consistent because these kinds of targets come in wide variety In general smaller objects and objects made from lower conductivity alloys such as iron bronze brass lead pewter and zinc will read lower on the effective conductivity scale Larger objects and objects made from higher conductivity alloys such as silver copper and aluminum will tend to read higher The notable exceptions are gold which usually reads low because it is rarely found in large pieces and zinc pennies which read moderately high because of their size and shape Although nails and other iron and steel objects will usually give low readings ring shaped pieces of iron for instance steel washers and harness rings will usually produce medium to high readings Flat pieces of iron or steel such as can lids will
52. ll 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 The OF TONES selections are 1 SINGLE MEDIUM PITCH TONE All types of metal induce the same tone 1F MEDIUM TO HIGH PITCH TONE varying in proportion to target signal strength Large shallow objects will produce a squeal The variable audio pitch provides you more information about the detected object but some people find the sound on strong signals too annoying 2F TWO TONES Similar to 1F except that iron produces a low pitched tone regardless signal strength Useful if you want to hear all targets and want to identify iron Most relic hunters prefer this selection 3H same as 3 except that nickels produce a high tone 3 THREE DIFFERENT AUDIO TONES Iron produces a low pitch tone Aluminum trash zinc pennies and nickels produce a medium tone High conductivity coins produce a high tone The 3 tone selection is often preferred for coinshooting Most users will set the discrimination level below nickels at about 25 and dig only objects that produce a consistent and repeatable high tone NOTE with this setting steel bottle caps may produce consistent high tones similar to coins See Capabilities amp Limitations section for advice on identifying steel bottle caps 4H same as 4 except that nickels produce a high t
53. ls 4 Release the MENU button and TOGGLE SWITCH 5 See the F symbol When the F disappears the detector is reset Controls DUAL FUNCTION MENU BUTTON LABS Toggle From Access bP or CL Process Settings Knob gt E Switch ON OFF amp VOLUME Knob Under the elbow This knob turns the machine on or off and controls speaker volume and headphone volume Knob position has no effect on detector s sensitivity or susceptibility to noise from electrical interference Controls continued 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 Step through the menu selections on the display With each push of the button the next menu selection will be highlighted The SETTINGS knob then allows you to change values for the highlighted selection 2 Recall the last setting which you adjusted After you have adjusted a setting an indicator will remain highlighted next to this menu selection One push of the button will recall that selection and display the stored value This recall function is useful for a value you want to adjust frequently such as the ground balance setting In order to adjust a stored value with the SETTINGS knob you must first press the MENU button to reactive the user interface 3 Press and Hold the MENU button to temporarily switch to the dE default process only w
54. move all components from box 2 Attach searchcoil to lower rod by lining up the holes Push coil knob through hole and tighten knob gently You will tighten up the coil knob later 3 Insert smallest rod into S rod S rod holds detector body Turn top locking collar counter clockwise to open up Push in pin on small rod Slide small rod into upper rod Click pin into hole and tighten locking collar firmly clockwise 4 Push lower rod into small rod as follows Turn locking collar counterclockwise to open up If plastic insert tab interferes push it down or turn tube upside down Push in pin to allow rod to slide in Slide lower rod in Click pin into any hole 5 Remove velcro strip from lower rod 6 Wrap cable around stem as follows Leave some slack in cable at base of lower rod Secure cable at base of rod with velcro strip Wrap cable loosely around entire stem up to bent part of upper rod You will re wrap the cable later after sizing the rods to your height Battery Compartment Headphone Jack Release Clip __ 2 way adjustable armrest On Off amp Volume Switch Menu Botton Settings Switch S Rod Dual function Trigger switch Silver sh 2 EG Stem vui Cable knurled knob Biaxial Searchoil Assembly continued 7 Push cable into connector on back of housing Do not twist the cable or plug 8 Tighten knurled cap nut by hand to secure cabl
55. ncommon in some regions 0 1 250 medium mineralization typical 0 03 75 light mineralization but common 0 01 25 light mineralization your G B setting may also be low blank lt 14 quartz amp coral white beach sands 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 an additional 30 minutes from the time the BATT legend starts flashing If using NiMH rechargeable batteries the display will remain stuck on the second or third bar for most of the battery life when it drops to the first bar the batteries will go dead within several minutes G B This is the ground balance setting 0 99 It is displayed when in the Manual G B menu setting or when the trigger is pushed for FASTGRAB computer assisted ground balancing SETTING This is illuminated when you in the menu When the word SETTING is indicated the number being displayed is a setting and not for instance a Target ID indication MESSAGES The small rectangular box at the bottom center of the LCD displays advisory messages If a metal object or highly magnetic soil is so close to the searchcoil that the signal is overloading the circuit the message OVERLOAD RAISE COIL will appear Such overloads will not harm the detector but the detector will not detect metals p
56. ne on and sets audio volume to maximum 4 When first turned on the F75 starts out in the Discrimination mode with Sensitivity preset to 60 Discrimination Level preset to 15 Number of Tones preset to 3 Process preset to dE Sweep the searchcoil from side to side parallel to the ground Keep the searchcoil moving over the ground If you stop moving the searchcoil the sound will also stop Probable target type will be indicated at the top of the LCD screen 5 the searchcoil is not in motion and not close to metal the detector should be silent 6 If you experience false signals from electrical interference from the soil itself or from lots of trash metal press the MENU button Sensitivity will be highlighted Rotate the Settings knob to the left counterclockwise Reduce the sensitivity setting until the false signals go away After 7 seconds the machine will exit the menu and return to normal operation 7 Find a patch of ground free of metal toss a coin on the ground and sweep back and forth over it a few times to get a feel for how the machine responds 8 You are now ready to search 9 Pull and hold the trigger switch with your index finger to pinpoint the exact location of targets making them easier to unearth When the trigger is pulled PinPoint is engaged The searchcoil need not be in motion to detect an object The 2 digit numeric display indicates approximate target depth in inches Assembly 1 Re
57. occasionally do the same Most targets can be identified accurately in air to a distance of about 10 inches The minerals in many soils will cause identification to be less accurate In most soils effective target identification can be had to a depth of at least 8 inches REQUIREMENT FOR MOTION PINPOINT FEATURE As with other modern metal detectors the F75 s searchcoil must be kept in motion in order to both detect and identify targets The All Metal modes are more forgiving of sweep speed variation than is the Discrimination mode The trigger activated PinPoint feature continues to detect metal if searchcoil motion stops over the target The PinPoint feature is used primarily to pinpoint the exact location of a target so that it can be retrieved with a minimum of digging and does not provide target identification Capabilities And Limitations continued GROUND BALANCING To achieve maximum depth in any detection mode as well as when using the PinPoint feature the F75 offers the ability to cancel out ground minerals either by manual adjustment or automatically using the FASTGRAB feature If you do not perform the ground balancing operation the Discrimination mode will usually still work fairly well but the ALL METAL modes will not The Pinpoint feature can be used for pinpointing objects at moderate depth in most soils without prior ground balancing The internal computer will not cancel saltwater so when detecting on wet ocean
58. old Toggle Switch c turn detector on while continuing to hold MENU and Toggle d release Menu and Toggle 2 Press MENU button 4 times to move down to the NOTCH feature then rotate the SETTINGS knob to the right until the number 40 appears then press MENU again to accept this notch value 3 Notice that a thin line appears across the word TAB printed on the top of the display 4 Press MENU again to exit the NOTCH feature 5 Targets in the first 1 2 of the TAB range TAB range is from 36 to 55 will be eliminated from detection 6 A half slash will be permanently displayed across the top left of the word TAB NOTCH allows you to select target ranges equal to 1 2 of each category for inclusion or exclusion from detection As you rotate the knob the target indicator will appear above the range currently selected If you set the notch value anywhere within the range the notch value will not necessarily stop at this number notch ranges are fixed as follows 1 1 7 iron 6 31 35 nickel 2 8 15 iron 7 36 45 tab 3 16 20 foil 8 46 55 tab 4 21 25 foil 9 56 60 zinc 5 26 30 nickel 10 61 65 zinc The following are characteristics of NOTCH programming As you rotate the knob to enter a notch range the target indicator block at the top edge of the screen illuminates to show you the range you are in After you have selected a notch a slash is illuminated over that range indicating that all targets within that range see
59. one Useful when coinshooting in a trashy area Discrimination Mede continued 4 dP FOUR DIFFERENT AUDIO TONES This selection is similar to 3 but with a fourth medium high tone for targets in the numeric range of 53 to 65 This four tone system is useful for searching in areas where there may be very old coins which register in this range DELTA PITCH This setting produces a tone whose pitch varies in relation to the visual ID number the higher the ID the higher the pitch Good for relic hunting This setting is also useful in areas with a high concentration of steel bottle caps Coins will produce a fairly constant pitch as you sweep back and forth Bottle caps produce inconsistent tones often with a squawk at the beginning of the sound Process Number Process This menu selection offers the user a choice among several different methods of audio discrimination to accommodate a variety of search conditions and personal preferences These methods differ in the way the signals are processed for analysis The Process Number selections are dE JE be PF bP DEFAULT PROCESS This is the best process to use for most conditions and is thus the default JEWELRY PROCESS Detector will be more sensitive to small and low conductivity metals like jewelry but will run noisier in trashy areas BOTTLE CAP MODE Response is modified so that steel bottle caps will usually produce inconsistent or non repeatabl
60. ontinuous information on battery condition and on ground mineralization which affects detection depth Help messages are automatically displayed on the bottom of the display when necessary LOW OPERATING COST The F75 is powered by four AA alkaline batteries which will typically last for more than 40 hours of use before needing replacement DESIGNED BY MANY OF THE INDUSTRY S MOST TALENTED ENGINEERS The lead engineers on the F75 design team were John Gardiner and David Johnson David Johnson s previous Fisher design credits include the CZ platform the Gold Bug series most of the 1200 series Impulse Underwater Detector CZ 20 Underwater Detector FX3 magnetometer the Gemini 2 box locator the XLT 16 Acoustical Leak Detector and the XLG 80 Ultrasonic Leak Detector John and David were supported by fellow electrical engineers Jorge Corral and Mark Krieger The mechanical design was a collaboration among David Johnson Brad Fulghum John Griffin and Tom Walsh MECHANICAL ENGINEERING While the F75 is robustly engineered for outdoor use it is not indestructible and it is not waterproof RESET function The F75 s microprocessor saves all settings which you input even after the power is turned off If you wish to reset the settings to the factory preset follow this process 1 Turn detector off 2 Press and hold the red MENU button and push forward and hold the TOGGLE SWITCH 3 Turn the detector on while you are still holding the contro
61. point toggle switch Bar graph ranges for a coin sized object are Shallow 0 4inches Medium 4 8inches and Deep 8inches CONF Target Confidence Indicator This 6 segment graphic indicates how confident the detector is of the 2 digit target identification it has assigned If all 6 segments are displayed you can be confident that the target ID is accurate If 3 or fewer segments are displayed the confidence is very low Junk targets tend to produce lower confidence indications than coin targets of similar electrical conductivity Sloppy sweep technique also reduces the confidence indication You can use this indicator to train yourself to sweep more skillfully BAR GRAPH magnetite This bar graph displays the magnetic mineralization factor or magnetic susceptibility of the soil Magnetic susceptibility is expressed in terms of the percent volume of the iron mineral magnetite which most black sand is made of The depth to which objects can be accurately identified is strongly influenced by the magnetic susceptibility of the soil High Fe O values have a greater effect on detection depth in the Discrimination mode than in the All Metal mode For the most accurate Fe O reading pump the searchcoil as though you were ground balancing Fe O approx Range micro cgs Description 3 7 500 uncommon but not rare heavy mineralization 1 2 500 heavy mineralization not uncommon in goldfields 0 3 750 heavy mineralization but not u
62. roperly under these conditions Raise the coil until the message disappears the siren sound will also stop Resume normal detection The message RAISE COIL only appears when using the be process accessed through the PROCESS menu selection This message indicates the presence of a target which may be too close to the searchcoil to be accurately identified For better target identification sweep the searchcoil farther away from the surface of the ground The message PUMP COIL TO GB will appear when you push the trigger forward to ground balance See the Ground Balance section of this manual for instructions The message CAN T GB can only appear when the trigger is pushed forward invoking FASTGRAB automatic ground balancing This message appears when the detector is unable to measure the soil in a manner suitable for ground balancing This message is usually the result of the presence of metal Try another spot to find an area free of metal BACK LIGHT The LCD is back lighted for use in low light and dark conditions The backlight is always illuminated but the illumination is usually not evident in daylight You cannot turn the backlight off The single high efficiency light emitting diode providing the illumination is a low current device and has a negligible impact on battery life Frequency Shifting One disadvantage of a highly sensitive metal detector is its susceptibility to electrical interference from other electronic devices
63. rth to see if any metal target is present Locate what seems to be a clear area and then Ground Balance Ground Balancing may be done automatically by pushing the trigger or manually if you are in All Metal mode After you have ground balanced sweep back and forth to see if there is little or no audible response to the soil This is best done either in All Metal mode or in Discrimination mode with discrimination set to zero Alternatively use the PinPoint trigger to check the spot If there is little or no response ground balancing was successful If there is still substantial response there may have been metal present where you attempted to ground balance so find another promising spot and try again If you cannot find a spot to successfully ground balance it is time to give up Reset the ground setting to 90 and then use the machine without ground balancing In most areas once you have ground balanced the ground balance setting will remain satisfactory for a long time However if the soil has been disturbed by digging or the addition of fill dirt or if you are in a geologically complex setting such as is commonly encountered in gold prospecting areas you may have to frequently perform the ground balancing procedure to accommodate changing soil conditions When you ground balance the numerical Ground Setting will momentarily appear on the LCD screen In general sandy or gravelly soils will tend to read in the 75 95 range light colored lo
64. s PinPoint does not require motion to detect metal PinPoint will detect objects while the coil is in motion and will continue to detect metal if searchcoil motion stops over the target Ground Pick Up If you have not performed the ground balancing procedure the PinPoint feature usually causes the ground to sound off This means that while pulling the pinpoint trigger the audio tone will get louder as you lower the searchcoil to the ground this is called ground pick up Since you want to hear the target rather than the ground we recommend first ground balancing in order to eliminate ground pick up Alternatively if you experience ground pick up you may place the coil very close to the ground off to the side of the target then pull the trigger and raise the searchcoil slightly while passing it over the target How to Pinpoint Position the searchcoil an inch or two 2 5 5cm above the ground and to the side of the target Then pull the trigger Now move the searchcoil slowly across the target and the sound will indicate the target s location As you sweep from side to side and hear no sound at the ends of the sweep the target is located in the middle of that zone where the sound is loudest and the audio pitch is highest If the sound is loud over a wide area the buried object is large Use the PinPoint feature to trace an outline of such large objects Narrow It Down To further narrow the field of detection position the searchcoil
65. t 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 The best solution is usually to reduce sensitivity If searching a very trashy area and unwanted signals are a problem search with the searchcoil 2 inches away from the ground Trash objects very close to the searchcoil will sometimes not be completely eliminated even when the discrimination setting should have eliminated the target Metal detectors are designed to see one metal object at a time Where there are two iron objects near each other the detector can be fooled into thinking that the gap between them is nonferrous metal This is common condition where a wooden building has burned or been torn down and the site is littered with nails A signal from a nonferrous metal object such as a coin will usually be repeatable whereas a false positive signal resulting from multiple or oddly shaped iron objects will seem to wander around and even to vanish Experienced detectorists call these non repeating signals and usually do not bother digging them since nonrepeating signals are almost always trash GROUND MINERALS Conductive mineral salts usually produce broad signals which will not be mistaken for a metallic object Common causes are concentrations of mineral fertilizer spots where evaporation has concentrated naturally occurring mineral salts residue from de icing salts and
66. t in tightly against the forearm such that you pry the sides loose each time you place your arm into the arm rest Arm Rest Position on Pole Remove the two bolts to position the arm rest farther forward or back to adapt to your arm s length To reinsert the bolts spin and twist them into place Be careful not to damage the power cable that runs through the aluminum tube Insert both bolts completely through both sides of the bracket before attaching the nutto the opposite Adjust the arm rest forward or back to side adapt to your arm s length After reinserting the bolts tighten them very securely You may need to use gloves for a firm grip As you swing the detector from side to side you want the bolts tight enough so that you do not feel any movement between the pole and arm rest mounting bracket If you notice unwanted movement while swinging detector check the tightness of the locking collars The locking collars must be rotated a full 270 to reach the locking position HEADPHONES not included The F75 is equipped with a standard 1 4 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 stereo plug should work headphones with a mono plug will not work Using headphones not supplied improves battery life and prevents the sounds from annoying bystanders It also allows you to hear subtle changes in the sound more cl
67. t with other metal detectors Shallow Targets Shallow targets tend to give multiple responses with the last response being the one that remains illuminated on the visual display This last response is usually sampled at the edge of the searchcoil and will tend to be inaccurate If you suspect a shallow target within 2 to 3 inches of the searchcoil lift the searchcoil slightly and slow down your sweep speed until you notice a single response consistently in the same place Large shallow targets can cause signal overload indicated by the siren sound In these instances raise the searchcoil until the overload warning disappears and sweep at this increased height Large Targets If an overload warning is not confined to a small spot you are probably overloading on a large object for example a large iron pipe reinforcing steel in concrete or buried sheet metal It is usually not possible to locate objects such as coins in close proximity to large masses of metal Using the special BOOST and CACHE LOCATING processes In situations where vegetation or other obstacles make it impossible to sweep the searchcoil close to the surface of the ground use the enhanced sensitivity of either the Boost bP or Cache CL Locating process to punch through the extra distance to the target Under most such conditions the Boost process will provide the best balance of depth and response The Cache Locating process will punch through even more dist
68. teel bottle cap will tend to bounce around a lot more especially with variations in sweep speed or angle By paying attention and taking this into account you can minimize the number of bottle caps you dig The information provided by the Visual Target ID may be different than the detector s Audio Feedback because the visual and audio systems are independent of one another The internal signals and algorithms controlling the Visual and Audio output are different Therefore what you hear or do not hear provides additional information regarding target ID For instance if discrimination is set at 12 and most sweeps result in no visual target ID the target is most likely iron even though the majority of the ID numbers will be greater than 12 The F75 has a tendency to up average nonferrous targets in the proximity of iron indicating 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 False Signals and Chatter At times the detector may beep when there is nothing there or it may seem like there is nothing there There are five major causes for this electrical interference nuisance buried objects ground minerals hot rocks and sensitivity set so high that internal circuit noise is audible The problem can usually be corrected by reducing the sensitivity setting but some
69. ter about two feet deep If searching around water be careful not to get the electronics housing wet Avoid salt spray as it will work its way into the control housing and damage the electronics such damage is not covered by the warranty Both fresh and saltwater beaches are popular places for metal detecting Vacationers lose money and jewelry playing in the sand and in the water It is usually easy to dig in a beach environment and metal detecting is permitted on most beaches Occasionally you may be able to help someone recover a piece of jewelry they have lost minutes before this is a gratifying experience DA ee Shallow Water Hunting continued When searching on a beach it is best to either search in Motion All Metal mode or to search with the discrimination level set just high enough to eliminate iron because the value of beach finds is largely in the jewelry rather than in the coins You will dig a lot of aluminum trash but the digging is easy and you can tell people that you are helping to clean up the beach and make it safer for people s feet We recommend the use of a special sand scoop for recovering valuables from the sand quickly most metal detector dealers sell these The electrical conductivity of the water itself can pose some challenges You may get false signals when going into and coming out of the water making it necessary to pay careful attention to keep the coil either in or out of the water but not to touch
70. tes gold is found in many places in the western states Alaska and in a few localities in the Appalachians The old saying Gold is where you find it means that to find gold you should look in areas where the yellow metal is known to be present 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 Gold is valuable because it is a scarce commodity Even in a good gold producing area you will often spend an entire day without finding any gold Meanwhile you will dig bits and pieces of other metal birdshot shells and bullets from hunting and target practice bits of rusted barbed wire chips off shovels and other mining tools rusted tin cans etc Hot rocks rocks containing concentrations of iron oxides that sound like metal when you pass over them are also a nuisance in many gold areas Discrimination is usually ineffective because the loss of sensitivity resulting from discrimination is enough to cause those little nuggets to vanish If you have gone many hours without finding gold and are wondering if there is something wrong with your metal detector or how you are using it the most important clu
71. tical plane normal to elbow 0 47 pounds 0 22 kg Varies with adjustment and user s stance and arm hand physiology axial moment 0 29 foot pounds 0 39 newton meters Varies with adjustment and user s stance and arm hand physiology lateral moment 5 2 foot pounds 7 1 newton meters VLF induction balance nominal 13 kHz quartz crystal timing reference 13158Hz 13100Hz 1043Hz 12987Hz 12931Hz 12876Hz 12821Hz 6 x 10 root Hertz detectivity 78 milliseconds approximately 10 000 micro cgs units volume susceptibility 40 000 micro cgs units with sensitivity lt 30 approximately 1 200 micro cgs units volume susceptibility 4 800 micro cgs units with sensitivity lt 30 Ground Balancing Range From ferrite to salt inclusive Discrimination Ground Suppression combination of second and third order methods ID Ground Suppression third order Battery Life Typically 40 hours with high quality alkaline batteries Estimated 80 hours with nickel oxyhydroxide batteries Estimated 65 hours with lithium iron disulfide batteries Operating Temp Range 4 to 122 degrees F 20 to 50 degrees C Operating Humidity Range 0 90 non condensing Quick Start Use your F75 right out of the box 1 Assemble the detector see instructions beginning page 4 2 Install four AA alkaline batteries All positive button end terminals point up 3 the knob located under the armrest fully clockwise This turns the machi
72. times other measures can also be taken ELECTRICAL INTERFERENCE Electrical Interference can be caused by power lines appliances computer equipment cell phones fluorescent and vapor type lamps household light dimmers other nearby metal detectors electric fences radio transmitters and electrical storms If you get abnormal noise while holding the searchcoil motionless in the air the cause is either electrical interference or internal circuit noise If it is electrical interference by walking around with the metal detector you can often follow the signal and track it back to the offending device simply turn the device off or come back at another time when it may be off If the interference is from power lines you might try another time of day Interference on power lines is usually caused by something connected to them which may be idle in the evenings or on weekends If the interference is from a communications or broadcast transmitting antenna reducing the sensitivity is usually your only recourse The F75 allows you to shift operating frequencies to avoid electrical interference See the Frequency Shifting section for information about this technique 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 pinpoin
73. to work into the noise if preferred SENSITIVITY This controls the signal gain and is adjustable from 1 to 99 Unlike the All Metal modes the Discrimination mode is designed to operate silently If you hear noise when there is no metal present or when the searchcoil is not in motion reduce the Sensitivity setting until the machine goes quiet NOTE there is no interaction between the sensitivity settings of the All Metal and Discrimination Modes The sensitivity system has two stages 1 29 low gain and 30 99 high gain As you lower sensitivity and cross the transition from 30 to 29 you may notice the background noise increase You may need to adjust to a setting of 29 or less to silence electrical interference or to prevent overload on highly mineralized ground or in saltwater You may also notice a shift in the ground balance setting over difficult ground conditions as you cross this transition DISCRIMINATION LEVEL This is adjustable from 0 to 65 and controls the range of objects to be eliminated from detection discriminated out or rejected Objects with numeric values below the selected discrimination level will not be detected NOTE the numerical range that pertains to each class of object is printed at the top of the visual display To eliminate iron a setting of 15 is usually about right A setting of 65 will eliminate aluminum trash and zinc pennies but nickels will also be lost unless you notch in nickels with the NOTC
74. unter s Code of Ethics Always check Federal State County and local laws before searching e Respect private property and do not enter private 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 natural resources wildlife and private property Act as an ambassador for the hobby use thoughtfulness consideration and courtesy at all times Never destroy historical or archaeological treasures All treasure hunters may be judged by the example you set always conduct yourself with courtesy and consideration of others 5 Vear Limited Warranty The F75 metal detector is warranted against defects in materials and workmanship under normal use for five years from the date of purchase to the original owner Damage due to neglect accidental damage or misuse of this product is not covered under this warranty Decisions regarding abuse or misuse of the detector are made solely at the discretion of the manufacturer Proof of Purchase is required to 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 To return your detector for service please first contact Fisher Labs for a Return Aut
75. vice by helping keep the place free of trash especially pieces of metal or glass that could endanger a child at play Be proficient at recovering targets without causing damage to the lawn Explain that whenever you find jewelry which has personal identification marks such as a class ring you make an attempt to determine the owner and to return it When someone who questions what you are doing understands that you are causing no damage and are actually performing a public service you will usually be welcome Detecting Activities continued Relic Hunting Relic hunting is searching for historical artifacts The most common desired objects are battlefield debris coins jewelry harness hardware metal buttons trade tokens metal toys household items and tools used by workmen and trades people The most common unwanted metal is iron nails fence wire rusted cans etc but some iron and steel objects such as weapons may be valuable If you are at a site where you may encounter unexploded ordinance use caution Most relic hunting locations are in fields forested areas and vacant lots where digging holes will not damage turf grass so having a detector with good depth sensitivity is important Some places are so littered with iron that it is necessary to discriminate out iron in order to be able to search even though you may miss some potentially valuable artifacts LA Before you go relic hunting obtain permission

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