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reading, say 38 feet. You know something’s haywire because you’re actually in 5 feet of water. Then the “38”starts flashing again, again, again, again, again, then, wait for it, shows a new reading: 457 feet! This is when you slap the unit on the side of the case and call it a few choice names, none of which are the one its manufacturer selected.
Typically this situation arises whenever the unit loses its “lock” on the bottom. It’s not receiving enough consistent ping returns from a dominant distance to determine a bottom depth. Cavitation is one possible reason, but in shallow water, it’s usually more often a result of combining too much power and sensitivity. Many of today’s units have enough power to return pings from well beyond 500 feet. If your sensitivity setting is high, imagine all those powerful pings bouncing back to the transducer when they only have to travel 10 feet. Try throwing ping pong balls as hard as you can at a wall 10 feet away and you’ll get the idea. Bombardment and overload easily come to mind. When the unit loses a clear bottom return, it starts searching deeper, and deeper, trying to regain a consistent one.
Lowrance’s HDS digital series and other digital processing sonar units may not be as susceptible to this as their analog predecessors, but they too can still have it happen. Oddly, the quickest way to resolve this problem is to simply turn the unit off, then back on again. It’ll almost always lock back on bottom quickly, though it may lose it again if the depth remains shallow. Since turning your unit off and on repeatedly is also intolerable, here’s a better remedy. Whenever fishing depths 10 feet or less for any length of time, put your unit in Manual mode. Select a 0-10 feet depth range. Turn off the digital depth display (if your unit allows) and take your depth readings from the side scale. Lower your Sensitivity setting to the point of retaining a solid bottom band. Don’t worry about seeing fish and every piece of structure. Depth is your main focal point, and possibly bottom composition. But if to prevent the unit from locking up, you have to lower the sensitivity to the point your bottom is simply a black line, no matter what its composition, do it. (Anytime you get into 7 feet or less and can’t see the bottom, you can always use your rod tip to periodically check bottom composition.) This approach will help you eliminate a lot of frustration when using your unit in shallow water.
ISSUE 2 June 2011
This DVD is designed to help you maximize your SONAR / GPS unit’s fish-finding and navigational abilities. Learn how to set up and operate the most important features that allow you to locate the best hotspots and catch more fish than ever before.
SPORTFISHING
SONAR & GPS TRAINING DVD
HERE’S WHAT IT INCLUDES: • Sonar / GPS Principles
• Keypad Orientation and Shortcuts
• Map / Chart Selection • Creating Playback Recordings
• Sonar / GPS Settings
• Sonar Image Interpretation
• Clean Up Setting
Principles covered on this DVD apply to these LOWRANCE Sonar / GPS Units:
LCX-104C LCX-110C LCX-111C HD LCX-112C LCX113C HD LCX-15 CI/CT LCX-15 MT LCX-16 CI LCX-17M LCX-18C LCX-19C
LCX-20C LCX-25C LCX-26C HD LCX-27C LCX-28C HD LCX-37C LCX-38C HD LMS-240 LMS-320 LMS-320DF LMS-330C
LMS-332C LMS-334C iGPS LMS-335CDF LMS-337CDF LMS-339C DF iGPS LMS-480M LMS-480MDF LMS-520C LMS-522C iGPS LMS-525C DF LMS-527C DF iGPS
www.sonargpstraining.com
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