User manual LOWRANCE X-20A

[. . . ] X-20A INSTALLATION AND OPERATION INSTRUCTIONS ·LOWRANCE ELECTRONICS, INC. LITHO IN U. S. A. 988-0105-36 12000 E. SKELLY DR. , TULSA, OK 74128 PDF compression, OCR, web-optimization with CVISION's PdfCompressor PDF compression, OCR, web-optimization with CVISION's PdfCompressor TABLE OF CONTENTS INTRODUCTION INSTALLATION POWER CONNECTIONS KEYBOARD BASICS OPERATION SENSITIVITY CHARTSPEED RANGE ZOOM DIGITAL FISH I. D. FEATURE 1 1 2 3 5 5 7 8 8 9 10 11 11 AUTO ALARMS CHARTALARM FISH ALARM SPEAKER LIGHT MODE SIMULATOR TRANSDUCERS AND CONE ANGLES SIGNAL INTERPRETATION FISH ARCHES WATER TEMPERATURE AND THERMOCLINES SURVEYING A LAKE BAIT FISH SPECIFICATION SERVICEINFORMATION TROUBLESHOOTING 12 13 13 13 14 16 17 18 18 20 21 22 22 23 23 Copyright © 1991, Lowrance Electronics, Inc. All featuresand specifications subjectto change without notice. [. . . ] The microcomputerplaces it at a level slightly above theminimum required to pick up the bottom signal. However, it's possible to changethe sensitivity level whilethe unitis in automatic. This maybe desirable ifthesensitivity level is not high enoughto showfish or other small detail. The unit will increase the sensitivity to pick up thebottomsignal, then add in the level you programmed. · To adjustthe sensitivitywhile the unit is in automatic, simply press the SENS. 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. Very small fish probablywill not arch at all. Medium sized fish will show a partial arch, or a shape similar to an arch if they're in deep water. Largefish will arch, butturn thesensitivity up in deeper waterto seethe 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 ofthe water. The smallerthe segment, the betterthe screen resolution will be. For the best results, turn thesensitivity up as high as possible withoutgetting too muchnoise on the screen. In mediumto deep water, this method should work to display fish arches. You can adjustthe sensitivityin thesamemanner whentheunit is in the manual mode. 6 19 PDF compression, OCR, web-optimization with CVISION's PdfCompressor Both 8 degree and 20 degree transducers give accuratebottom readings, even though the bottom signal is much wider on the 20 degree model. This is because you are seeing more of the bottom. Remember, the shallow edge of the signal showsyou the true depth. Therest of the signal tells you whetheryou are over rocks, mud, etc. CHARTSPEED SIGNAL INTERPRETATION Your unitgivesan accuratepicture of thebottomthat your boat is passing. 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 narrows , 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. 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'sheight. [. . . ] The words " ChartAlarm" flashesin the lowerright cornerofthescreen. A verticalbar also displayson the leftside ofthe screen. It will stay on thescreen foreight seconds or for eightsecondsafteryouhavefinished adjustingit. This is theChartAlarm's"window. " Any echo that appears between thetop and bottom of this bar will sound the alarm. [. . . ]