Humminbird Side Imaging Forums

Side Imaging Forums => 898c SI => Topic started by: yenrec on March 10, 2013, 06:16:47 PM

Title: wrong depth reading
Post by: yenrec on March 10, 2013, 06:16:47 PM
since i bought the unit i have noticed it off and on, on different bodies of water, that my sonar will read about 10 feet deeper than it really is. Watching the spitfire sonar i can tell it will be 8-9' deep, but the depth reading shows 18-19' feet deep. Once again i have noticed this on different bodies of water, and its started to bother me enough to seek out help. This is occurring while i am drifting with the current, breeze, or the trolling motor, so i know high speed is not the issue. Thanks in advance for any help guys!
Title: Re: wrong depth reading
Post by: ITGEEK on March 11, 2013, 08:37:46 AM
This could be electrical interference.  It will make
the depth erratic.  The biggest culprit is usually the
trolling motor.
Try cutting off everything electrical on your boat except
the sonar, and drift around and see if the depth
is correct.
Title: Re: wrong depth reading
Post by: RGecy on March 11, 2013, 06:41:59 PM
Also can be from second sonar return showing up very strong.  Check the angle of the transducer and make sure it is not pointing too much under the boat.  The sonar will bounce between the surface and the bottom and will reflect easily off the boat, causing this second return.   

Robert
Title: Re: wrong depth reading
Post by: Humminbird_Greg on March 12, 2013, 12:45:52 PM
Which model Humminbird do you have?
What software version is it running?
Where is the transducer mounted?

If it is not electrical interference from something on your boat or sonar interference from another sonar unit try adjusting the Surface Clutter menu.

If that does not help try setting the Water Type menu to the “Salt (deep)” menu setting.
Title: Re: wrong depth reading
Post by: Patty on April 09, 2013, 06:46:23 PM
Regarding shallow water readings, this is due to the signal strength and strong signal return from the hard bottom in shallow water. What happens is that the signal bounces back and forth causing the unit to have a hard time locking on the depth. The unit has a feature that adjusts the power output to minimize irregularities, but it sometimes takes a minute to adjust itself. That's why you might hear a ticking sound from the transducer in shallow water since it is sending pulses to adjust itself in these conditions.
I do know that some of the more recent software updates have addressed shallow water performance issues. There have been a couple software updates since the version you have. Again, the latest update should improve performance.
In some case you might see the depth reading at say... 14ft while you see the actual depth at 7ft on the depth scale on the screen as an example. You'll actually see a double echo at 7ft and 14ft. This is one of those anomalies where the double echo due to the strong signal return reads the second echo/signal return... instead of the actual depth at 7ft. In cases like this I just know by looking at the screen that the actual depth is 7ft, not 14ft. Software updates have helped address this, but it is not foolproof.. again one of those sonar anomalies. So when in doubt, what you see on your screen is correct, not necessarily the depth readout.

This is a Quote I got from a Humminbird guy in my area about my issues with shallow water readings....
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