Lowrance electronic X-20 User's Manual
Contents
1. LITHO IN U S A G X 20 CVISION TECHNOLOGIES INSTALLATION AND OPERATION INSTRUCTIONS i M LOWRANCE ELECTRONICS INC 988 0105 17 12000 E SKELLY DR TULSA OK 74128 TABLE OF CONTENTS INTRODUCTION INSTALLATION POWER CONNECTIONS NOISE TRANSDUCER KEYBOARD BASICS OPERATION SENSITIVITY CHART SPEED RANGE ZOOM DIGITAL FISH I D FEATURE AUTO ALARMS CHART ALARM FISH ALARM SPEAKER LIGHT MODE TRANSDUCERS AND CONE ANGLES SIGNAL INTERPRETATION FISH ARCHES WATER TEMPERATURE AND THERMOCLINES SURVEYING A LAKE BAIT FISH HOW TO OBTAIN SERVICE SPECIFICATIONS GLOSSARY Copyright 1989 Lowrance Electronics Inc All rights reserved All features and specifications subject to change without notice 2i E ACTUAL UNRETOUCHED PHOTOGRAPHS TAKEN ON GRAND LAKE OF THE CHEROKEES OKLAHOMA SENSITIVITY The ability of a sonar unit s receiver to display targets Increasing the sensitivity allows weaker targets to be displayed Also called gain SCROLL SPEED See CHART SPEED SHOOT THROUGH HULL A transducer installation which allows the sonar signals to pass through a fiberglass hull without cutting a hole in the hull SUPPRESSION A method used in some sonar units to help eliminate interference or noise SURFACE CLARITY CONTROL Reduces or eliminates undesirable signals displayed near the water s surface Also called S2. chart speed range zoom and chart alarm 4 Operating Current 200 ma lights off 500 ma lights on Operating Voltage 9 15 vde Number of pixels 50 x 27 vertical x horizontal 1350 Total 5 per minute minimum 32 per minute maximum Display Scroll Speed Maximum Chart Range 180 feet Maximum Digital Range 400 feet GLOSSARY ANCHOR WATCH A setting of the sonar unit s alarm The alarm activates when the boat drifts into shallower or deeper water than the alarm set points BACK LIGHTED A display or keyboard illuminated from behind by a light Back lighted displays are essential when night fishing or navigat ing CAVITATION Air bubbles created by the high speed movement of a boat or transducer through water CHART SPEED 1 The speed of the chart paper on a paper graph recorder 2 The speed of an image across the screen of a liquid crystal graph Also called scroll speed CONE ANGLE Angle of the transducer s cone of sound Lowrance has transducers available with cone angles from 8 to 45 degrees to suit the varying needs of fishermen CRT Abbreviation for Cathode Ray Tube See Video Graph DEFINITION The ability of a sonar unit s display to show detail A display with high definition can show more detail than one with low definition DISCRIMINATION A feature available on Lowrance L C G s and paper graphs that separates false echoes from true target information of i BAIT FISH The
3. and more FISH ALARM An alarm that activates when a fish or suspended object is detected FISH ARCH A sonar with good resolution and definition can display suspended targets as upside down Vees or arches These signals are typically fish hence the name Fish Arch See page 20 for more information FLUSH MOUNT A transducer that is installed with the bottom of the transducer flush with the bottom of the hull GIMBAL BRACKET A bracket used to install a sonar unit perma nently The sonar unit can rotate in the bracket for the best viewing angle GRAYLINE This feature shows the relative strength of signals dis played on the screen Signals weaker than the GRAYLINE setting are displayed in black stronger targets are gray It also gives clues to the composition of the bottom In other words you can tell if the bottom is soft or hard A hard bottom retums a strong signal causing a wide gray line A soft muddy or weedy bottom retums a weaker signal which is emphasized with a narrow gray line IN DASH A sonar unit installed through a hole in the boat s dash Usually the face of the sonar is flush or nearly so with the dash kHz Kilohertz A measurement of frequency Your Lowrance sonar operates at 192 Kilohertz 192 000 cycles per second LCD Liquid crystal display The screen or display of a Liquid Crystal Graph sonar instrument LCG Liquid Crystal Graph NOISE Any undesired signal Electrical noise is
4. importance of bait fish to successful fishing can t be over empha sized They are the principal food of all game fish in most waters Bait fish are the plankton feeding forage fish such as minnows and shad Bait fish can also be the young of game fish such as crappies bluegill and bass Most bait fish concentrate within five feet of the surface where sunlight promotes the growth of the plankton on which they feed One method of fishing is to use the unit to find the bait fish first A school of bait fish will look like a cloud on the unit s display Usually game fish will be nearby often directly beneath the school of bait fish HOW TO OBTAIN SERVICE If you have a problem with your sonar unit please give us a chance to help before sending it in for repair Call or write the Factory Customer Service Department at 1 800 331 3889 extension 401 toll free Okla homa residents call 918 437 6881 extension 401 collect Please detail the problem you are experiencing The service depart ment may be able to save you the inconvenience of returning your unit If the unit must be retumed pack it carefully so it won t be damaged It is advisable to insure the unit in case it s lost or damaged during transit Mail To Lowrance Customer Service 12000 E Skelly Drive Tulsa OK 74128 SPECIFICATIONS Dimensions 5 7 8 H x 7 3 4 W x 3 7 16 D Weight 1 3 4 pounds Transmitter frequency 192 kHz Output Power typical 275 watts peak to
5. most from your sonar You can program the X 20 to sound an alarm when a fish or other sus pended object enters an alarm zone You can zoom in and separate fish from structure and other targets To get started with your X 20 first read the installation section This is where it all begins and improper installation can cause problems down the road After you ve read these instructions and installed your X 20 read the rest of this manual in detail The more you know when you get to the water the more your sonar unit will do for you Take this manual for reference when you head for the water INSTALLATION Mounting Install the X 20 in any convenient location provided there is clearance when tilted for the best viewing angle Holes in the bracket base allow wood screw or through bolt mounting Place a piece of plywood on the back of thin panels to secure the mounting hardware Make certain there is enough room behind the unit to attach the power and transducer cables You can route the power and transducer cables through the one inch hole in the base of the gimbal bracket Then pass them through a hole in the mounting surface First pass the transducer connector and cable up through the hole and gimbal bracket Then push the power cable wire down through the bracket and dash After routing the cables fill the hole with silicone rubber adhesive RTV Offset the bracket to cover the majority of the hole Power Connections The X 20 op
6. shorter as shown in B As the cone leaves the fish the distance increases again as shown in C When the Fish I D feature is off the depth of the water will affect the size and shape of the fish arch due to the cone angle diameter For example if the cone passes over a fish in shallow water the signal displayed on the unit may not arch at all This is due to the narrow cone diameter and the resolution limitations of the display 20 CHART SPEED At power on the chart speed scrolls at a preset speed To change the speed press the CHART SPEED key The word CHART will flash on the right side of the display A vertical bar will also appear on the left side of the screen This indicates the current chart speed Next press the up arrow key if you wish to increase the chart speed Press the down arrow key to decrease it When the chart reaches the desired speed release the key There are five steps of chart speed When the chart speed reaches its maximum or minimum level the unit will sound a tone To view the chart speed without changing it press the CHART SPEED key The chart speed bar will appear for eight seconds At times it is desirable to stop or freeze the display to examine an echo before it scrolls off the screen Pressing the SENS and CHART SPEED keys at the same time will freeze the display Press the SENS and CHART SPEED keys again to start the display moving at the last chart speed setting If the digital son
7. CC THERMOCLINE A layer of water caused by the meeting of warm and cool layers of water The thermocline provides the temperature most fish prefer TRANSDUCER The element of a sonar system that converts the electrical energy from the transmitter into ultrasonic sound waves When a return echo strikes the transducer it converts the sound waves into electrical energy which is received and displayed by the sonar unit TRANSOM MOUNT A method of mounting transducers or other sensors on the transom of the boat UPPER LOWER LIMIT These are the range limits displayed on the Sonar screen or paper The upper limit is shown at the top of the display while the lower limit is at the bottom For example a 20 to 30 foot range has 20 feet as the upper limit and 30 feet as the lower limit VIDEO GRAPH A sonar unit that uses a CRT or television type display WINDOW A vertical segment of the depth range For example an upper limit of 20 feet and a lower limit of 50 feet creates a 30 foot window ZOOM A feature that enlarges targets on the display and shows greater detail INTRODUCTION Welcome to the world of sportfishing sonar Your Lowrance X 20 is a high quality sonar designed for both professional and novice users These units have an automatic feature that finds and displays the bottom depth fish and structure As you become familiar with your X 20 you can fine tune the unit to the surrounding conditions to get the
8. SUN 77 EPILIMNION 76 75 ktm LS THERMOCLINE Es MOST PRODUCTIVE 2 Ed ZONE FOR FISHING Ne 56 VARIFS IN DEPTH DUF TA WIND CURRENTS SEASONS 50 LOW OXYGEN CONTENT HYPOLIMNION 47 OPERATION SENSITIVITY When first turned on the X 20 is in the AUTO SEARCH mode The micro computer automatically adjusts the sensitivity and range to find and lock onto the bottom The digital depth flashes 0 until it finds and locks onto the bottom You can leave the sensitivity in the automatic mode or manually adjust it to suit conditions You may need to increase the sensitivity to show fish symbols when the unit is in automatic To do this first press the SENS key The letters SENS will flash on the right side of the display A vertical bar appears on the left side of the screen See below This indicates the sensi tivity level To increase the sensitivity press and hold the up arrow key until the sensitivity is at the desired level The down arrow key de creases sensitivity in the same manner Notice how the sensitivity bar moves as you change settings It will move up when the sensitivity is increased You ll also see the change on the display After you ve finished setting the sensitivity level the letters SENS andthe sensitiv ity bar will disappear after eight seconds When the Fish I D feature is off the sensitivity can be increased more even if the unit s automatic feature is on This will help d
9. an area about six feet across The 8 degree transducer covers only about a two foot circle The 20 degree transducer is almost always the best to use in fresh water the 8 degree mostly in salt water In a deep water environment 300 feet fresh water 100 feet salt water the narrow cone angle is more desirable Since the sound energy is concentrated in a smaller area it can penetrate to much deeper depths 18 L B ZOOM Manual Mode Zoom operates differently when the unit is in the manual mode The range doesn t change when the zoom key is pressed Instead press the down arrow key to shift the range down in one foot increments The up arrow key shifts the range up in one foot increments For example if the unit is on the 0 60 foot range and the manual mode is on pressing the zoom key then the down arrow key once will move the 0 60 range to 1 61 The best way to use this feature is to change the range to a smaller one then press the zoom key shift the range until the area is displayed that you want zoomed For example if the bottom depth is 50 feet and you wish to enlarge the area immediately above it first change the range to 0 15 feet Now press the zoom key Finally press the down arrow key until the bottom appears Now you have a fifteen foot zoom window around the bottom signal pum x DIGITAL Built inside the X 20 is a complete digital sonar It works automatically to dis
10. ar is on the bottom depth will still be displayed The digital does not stop when the chart is in the freeze mode RANGE The range automatically changes to keep the bottom signal on the display when the unit is in automatic The range cannot be manually changed when the unit is in the automatic mode The range can be changed in manual mode There are six ranges available 0 5 15 30 60 120 and 180 feet To change the range first make certain the word AUTO is off Then press the RANGE key The word RANGE will flash on the right side of the screen Next press the up arrow key to switch to a shallower range or press the down arrow key for a deeper range The range annunciator will stop flashing eight seconds after the last key was pressed ZOOM Automatic operation Press the ZOOM key to double the size of the targets on the display It works by enlarging the bottom half of the selected range For example if the range is 0 60 feet and the zoom key is pressed the new range will be 30 60 feet If the unit is in automatic the bottom will be tracked in this 30 foot window There are two exceptions to this rule 1 If you re on the 0 15 range and press the zoom key the new range will be 10 15 2 There is no zoom on the 0 5 range 10 Both 8 degree and 20 degree transducers give accurate bottom read ings even though the bottom signal is much wider on the 20 degree model This is because you are seeing more of th
11. caused by engine ignitions systems radios etc Acoustic noise is caused by the vibration of the engine or other mechanical sources Noise appears on the display as random dots or lines 26 NOISE Minimize electrical noise by routing the power cable away from other possible sources of electrical interference One of the largest noise generators is the engine s wiring hamess that runs from the engine to the instrument panel This harness usually contains a wire for the tachometer which radiates RF radio frequency energy For best results keep the power and transducer cables away from the engine wiring Also bilge pump wiring can sometimes radiate noise so try to keep the X 20 s cables away from those wires VHF radio antenna cables typically radiate RF energy at higher power levels than the engine s wiring hamess It is important to keep the X 20 s power and transducer cables as far away as possible from VHF radio cables If interference begins at slow boat speeds worsening as the boat speed increases then a probable cause is acoustic noise or cavitation This noise is not electrical but rather mechanically induced noise from the transducer Stop the boat put the engine in neutral and increase the Rpm If the noise does not increase on the display then it is cavitation Usually air bubbles passing over the face of the transducer create acoustic noise The faster a boat travels the more air bubbles increase and generate nois
12. criminate between the valid bottom echoes and false echoes from fish thermoclines or other signals The digital display will show only the bottom depth l At power on the digital will flash 0 until it has locked on to the bottom signal Once it has acquired the bottom depth it will display it in the lower left side of the display FISH I D The Fish I D feature is automatically on when the unit is first turned on The computer inside the unit analvzes all echoes filtering out unwanted signals It helps eliminate surface clutter thermoclines and other un desirable signals The remaining suspended targets are usually fish Targets that are identified by the unit as fish are displayed as small medium or large fish symbols on the display These symbols are shown according to the relative size of the fish as seen by the unit The Fish I D feature can only be used in automatic If you wish to turn it off or back on again press the FISH I D key If you press the FISH I D key when the unit is in manual it will put it in automatic and enable the Fish I D feature To show fish symbols you must be traveling at a slow trolling speed There should be some movement of the boat for the Fish I D feature to work properly If you have difficulty showing fish symbols try increasing the sensitivity NOTE The Fish I D fea ture cannot distinguish between fish and other suspended objects such as turtles tree branches
13. e bottom Remem ber the shallow edge of the signal shows you the true depth The rest of the signal tells you whether you are over rocks mud etc SIGNAL INTERPRETATION Your unit gives an accurate picture of the bottom that your boat is pass ing A bottom of firm sand gravel shell or hard clay returns a wide bottom signal If the automatic feature is off and the bottom signal nar rows then it means that you have moved over a mud bottom Mud absorbs the sound wave and returns a weak signal Turn up the sensitivity to see a better bottom signal LE MODE 5 All chart High Speed Scroll In this mode the chart scrolls at high speed The chart speed can be adjusted with the CHART SPEED key if desired a Chart uses full screen b No digital depth indicator c No FASTRAK d No automatic operation al lowed e No Fish I D feature or Fish Alam f Chart alarm is allowed TRANSDUCERS AND CONE ANGLES The sound waves from the transducer spread out into the water in a cone shaped beam This looks much like the beam from a flashlight The angle between the outside edges of the cone is the cone angle Lowrance offers a choice of transducers with either an 8 or 20 degree cone angle Typically wide cone angle transducers 20 degrees are ideal for operating in shallow to medium water depths The 20 degree cone angle allows you to see more of the underwater world In 15 feet of water the 20 degree cone covers
14. e on the display To eliminate this problem read the transducer installation section for proper mounting techniques TRANSDUCER Transducer installation instructions are packaged separately with the transducer Please read the instructions carefully before you install the transducer Periodically wash the transducer s face with soap and water to remove any oil film that may collect Oil and dirt on the face will reduce the sensitivity or may even prevent operation Paint transducers on salt water boats with a thin coat of anti foulant paint to prevent organisms from growing If unchecked barnacles and other marine growth will cause a decrease in the transducer s sensitiv ity Do not use a metal based anti foulant paint as it will decrease the transducer s sensitivity There are special anti foulant paints specifi cally designed for transducers They re readily available at most marine dealers a E FISH ALARM o KEYBOARD BASICS This section gives a brief explanation of the keyboard Read the Operation section for a detailed description of each key s operation These keys turn the unit s power on and off To turn it on simply press the ON key To turn it off press the OFF key Pressing any key generates a tone or beep This tells you that the unit has accepted a command AJ UP and DOWN ARROWS These keys are used to adjust virtually every feature and function on the unit Use these keys to adjust the sensitivity
15. erates from a 12 volt battery system Attach the power cable to an accessory or power buss f you have problems with electrical interference then attach the cable directly to the battery Electrical interference shows as random dots on the display whenever the boat s engine or an accessory is on The power cable has two wires red is the positive lead and black is negative or ground Attach the in line fuse holder to the red wire on the power cable with the crimp connector The other end of the fuse holder attaches to the battery or accessory buss If the cable is not long enough splice ordinary 18 gauge wire onto it Be certain that the fuse holder is as close to the power source battery or accessory buss as possible This protects the power cable and your X 20 in the event of a short Use a 3 amp fuse The X 20 has reverse polarity protection No damage will occur if the power wires are reversed However the unit will not work until the wires are attached correctly 12 VOLT BATTERY OPERATING FREQUENCY Frequency of a sonar unit s transmitter and receiver See kHz OUTPUT POWER The amplitude of electrical energy transmitted from the sonar unit to the transducer Measured in watts the higher the output power the deeper a sonar unit can read and more detail can be displayed PIXEL The small dots or squares on a liquid crystal display or CRT PIXEL DENSITY The number of pixels per square inch on a liquid crys
16. he A screen This gives a Pi rapid update of condi tions directly under the U fi boat Echoes are also u scrolled normally across the display The Fish I D feature is not avail able with this mode r 13 Uc AUTO When the unit is first turned on the automatic feature is enabled It works automatically to find and display the bottom depth The sensitiv ity and range are also adjusted to keep the bottom signal on the screen at all times To turn the automatic feature off simply press the AUTO key once The word AUTO will disappear from the display signifving the automatic sensitivitv and chart range features are off This also turns the Fish D feature off at the same time The digital remains on To return the unit to the automatic mode press the AUTO key again This will reset the sensitivity so you may wish to increase it to see fish or other detail This will not turn the Fish I D feature on You will have to press the Fish I D key to turn it on KEEGNEBRVBRRGZECERHEMNEKEREEN f i ALARMS The unit has two different alarms a chart alarm and Fish Alarm The chart alarm consists of a bar that displavs on the left side of the screen The alarm chirps whenever the unit detects an echo inside the boundaries of the bar Fish Alarm sounds an audible alarm when fish or other suspended objects are detected It works in conjunction with the Fish I D feature To separate the alarms the fish alarm s tone sou
17. he promising spots in relation to landmarks on shore As you go about your survey your unit will tell you the depth and type of bottom It will also reveal suspended fish Keep a few marker buoys in the boat ready to toss overboard When the unit indicates a school of fish throw the buoy out With the school thus marked you can make your turn and come back to fish in exactly the right spot This is essential when you re far from shore on a big lake Unless you mark the school of fish when you re over it you may not be able to find it again WATER TEMPERATURE AND THERMOCLINES Water temperature has an important if not controlling influence upon the activities of all fish Fish are cold blooded and their bodies are always the temperature of the surrounding water During the winter colder water slows down their metabolism At this time they need about a fourth as much food as they consume in the summer Most fish don t spawn unless the water temperature is within rather narrow limits A surface temperature meter such as Lowrance s LDT 3000 helps identify the desired surface water spawning temperatures for various species Trout can t survive in streams that get too warm Bass and other fish eventually die out when stocked in lakes that remain too cold during the summer While some fish have a wider temperature tolerance than others each has a certain range within which it tries to 83 SURFACE LAVFR ABSORBS HEAT FROM THE
18. isplay fish and other small detail When automatic is turned off the sensitivity level can be increased to its maximum level With high sensitivitv settings a second bottom echo second echo mav appear This is normal It s caused by the returning signal reflecting off the surface of the water Then it makes a second trip to the bottom and back again Remember when the unit s automatic feature is on the receiver s sen sitivitv automatically adjusts to the surrounding conditions The micro computer places it at a level slightly above the minimum required to pick up the bottom signal However it s possible to change the sensitivity level while the unit is in automatic This may be desirable if the sensitiv ity level is not high enough to show fish or other small detail The unit will increase the sensitivity to pick up the bottom signal then add in the level you programmed To adjust the sensitivity while the unit is in automatic simply press the SENS key Then press either the up arrow key to increase it or the down arrow key to decrease it As you press the arrow key the sensitivity bar moves up or down according to the sensitivity level chosen You can adjust the sensitivity in the same manner when the unit is in the manual mode BOATS DIRECTION OF TRAVEL m B zm E LL a a A B C Very small fish probably will not arch at all Medium sized fish will show a partial arch or a shape si
19. milar to an arch if they re in deep water Large fish will arch but turn the sensitivity up in deeper water to see the arch Because of water conditions such as heavy surface clutter thermoclines etc the sensitivity sometimes cannot be increased enough to get fish arches One of the best ways to get fish arches is to expand or zoom a segment of the water For example from 45 to 60 feet The smaller the segment the better the screen resolution will be For the best results turn the sensitivity up as high as possible without getting too much noise on the screen In medium to deep water this method should work to display fish arches zt BIB Big rocks or stumps on a smooth bottom send back signals above the bottom level signal The height of the signal depends on the target s height As you pass over a post it should be clearly visible as a short line extending above the bottom signal A steep slope returns a wide signal the steeper the wider Signals returned from a high underwater cliff are usually the widest of all Brush usually lies on the bottom and shows up as clumps rising above the bottom signal Brush signals look similar to large rocks however their signal is not as strong as rock FISH ARCHES Fish arches are created when the cone of sound passes over a fish The distance to a fish when the cone first strikes it is shown as A on the next page When the center of the cone strikes the fish the distance is
20. nds different than the chart alarm Both alarms mav be used at the same time 3 CHART ALARM To set the Chart Alarm press the CHART ALARM key on the keyboard The words Chart Alarm flashes in the lower right corner of the screen A vertical bar also displays on the left side of the screen It will stay on the screen for eight seconds or for eight seconds after you have finished adjusting it This is the Chart Alarm s window Any echo that appears between the top and bottom of this bar will sound the alarm Adjust deep end of this bar to make a smaller or larger alarm window The shallow end is automatically adjusted by the unit so it won t be triggered by surface clutter or other false signals Next press the down arrow to move the bottom of the bar deeper or press the up arrow to move it shallower Eight seconds after the last button is pressed the alarm bar will disappear When the Chart Alarm signal is on the alarm is active If you wish to view the Chart Alarm bar simply press the CHART ALARM key The bar will be displayed for eight seconds Any target that appears on the left side of the screen in the area covered by the chart alarm bar will trigger the alarm If the range is changed the Chart Alarm may need to be changed also since it does not track range settings 14 To turn the Chart Alarm off press the CHART ALARM key then move the bottom of the bar all the way to its shallowest position usi
21. ng the up arrow key FISH ALARM Use the FISH ALARM for a distinctive audible alarm when fish or other susupended objects are detected by the FISH I D feature Press the FISH LD and the AUTO keys at the same time The words FISH ALARM displays at the bottom right side of the screen The audible alarm sounds each time the Fish I D feature detects a fish or other suspended object There is a different tone for each fish symbol size To tum the Fish Alarm off press the FISH I D and AUTO keys at the same time SPEAKER The speaker can be turned on and off by pressing the up and down arrow keys at the same time The speaker is represented by a note symbol above the arrow keys Whenever it is enabled a note symbol appears on the right center side of the display The speaker is enabled when the unit is tumed on NOTE This applies to the alarms only The unit will still sound a tone when a key is pressed and the speaker is turned off LIGHT A light allows operation of the unit at night Tuming the unit on causes the lights to flash for six seconds Press the RANGE and ZOOM keys at the same time and the lights will stay on To turnthe lights off press the RANGE and ZOOM keys again The lights will also go out when the unit is tumed off
22. peak 34 4 watts RMS Receiver Sensitivity 82 db temperature stabilized 24 SENS CHART SPEED RANG GHART ALARM STOP CHART SPEED es toon AN CHART E FISH ALARM J SENS This key and the arrow keys adjust the graph s sensitivity The digitafs sensitivity is adjusted by the unit automati cally The receiver has 32 steps of adjustment CHART SPEED Vary the speed of the chart with this key and the arrow keys There are 5 steps of chart speed adjustment RANGE The depth range is changed with this key and the arrow keys The ranges vary from 0 5 feet to 0 180 feet CHART ALARM Using this key activates the chart alarm A bar appears on the left side of the display when the chart alarm is ad justed Any target that appears on the screen between the top and bottom of the chart alarm bar triggers the alarm r E FISH Lu J GIE MODE The X 20 has five different screens or modes of opera tion Use this key to switch between modes FISH I D I D This key tums the Fish I D feature off and on XT FISH ALARM Press both the Fish I D and the AUTO key at the same time to activate the Fish Alarm This is an audible fish alarm AUTO AMISM Turning the unit on enables the automatic mode To switch to the manual mode press the AUTO key You can return the unit to automatic at any time by pressing the AUTO key again stay Schooling fish suspended over deep water lie at the level that
23. provides this temperature We assume they are the most comfortable here The temperature of water in the lake is seldom constant from top to bottom Layers of different temperatures form and the junction of a warm and cool layer of water is called a thermocline The depth and thickness of the thermocline can vary with the season or time of day In deep lakes there may be two or more at different depths Thermoclines are important to fishermen because they are areas where fish are active Many times bait fish will be above the thermocline while larger game fish will suspend in or just below it The X 20 can detect this invisible layer in the water but the sensitivity will probably have to be tumed up to see it SURVEYING A LAKE The most successful anglers on any body of water are those who fish it day after day and year after year Eventually they leam the hot spots that produce fish consistently They discover through experience where and at what depth they can expect to find the fish they want at any season And they realize that these productive areas change throughout the year depending on water level temperature food and other factors With the X 20 anyone can eliminate guesswork and concentrate on the areas where fish are likely to be Even if it s the first time on the lake The most efficient way to become acquainted with a body of water is to survey it with your unit Start with a map of the lake if possible and indicate t
24. tal display Typically the greater number of vertical pixels the better the resolution PULSE LENGTH The amourt of time that the sonar transmits This is measured in micro seconds The shorter the pulse length the better the resolution For example a 30 micro second pulse length is equal to a one nch resolution RANGE The section of water shown on the sonar display For example a 60 foot range has zero for the upper limit and 60 for the lower limit REMOTE An intelligent repeater unit that receives depth information from another sonar unit A remote doesn t have a transmitter or re ceiver However it does have it s own features that are adjustable and operate separately from the master RESOLUTION The ability of a sonar unit to separate targets from each other or from the bottom SCALE The markings on a sonar unit s display To determine the depth of a target simply compare the target s location to the location of the scale markers on the display SECOND ECHO Another echo that registers at roughly twice the depth of a target echo This is caused by the sound waves reflecting off the bottom striking the surface of the water travelling to the bottom again and returning to the surface SECOND FUNCTION KEY A button that converts the functions of the primary keys to other functions The Discrimination feature on Lowrance sonar units removes manv false signals from other sonars acoustic and electrical sources
25. trotlines submerged floats or other inanimate objects The micro com puter in this unit is so phisticated but it can be fooled The most difficult challenge is individual tree branches extending out from groups of branches These can be mis identified as fish by the Fish LD feature Also large amounts of noise can fool the Fish 1 D feature This is usu ally caused by a poor transducer installation Although the Fish I D feature isn t perfect it can be a valuable aid to the fisherman 12 MODE 3 Big digital a The digital depth numbers use the lower quarter of the display The depth is displayed in tenths of a foot to 99 9 feet then it is dis played in whole numbers b No FASTRAK MODE 4 Depth only displayed in large digits No chart is displayed MODE The X 20 has five different screen modes To change modes press the MODE key Keep pressing the MODE key until the desired screen appears A summary of the different screen modes follows MODE 1 This is the default mode used when the unit is first turned on It has the following features MEER a Small digital depth dis play in lower left corner It does not show tenths of a foot Normal chart display b No FASTRAK MODE 2 This is the same as mode 1 except it has FASTRAK This displays on the right side of the screen It con _ n verts all echoes to hori i U zontal bars when thev l first appear on t
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