Humminbird Side Imaging Forums
General => General Discussion => Topic started by: sarasotawingman on July 02, 2012, 07:46:00 PM
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Noticing the last couple times that I've been out on the boat my 898c si seems to be a bit off. Various landmarks and channel depths are off. For example I went under a bridge and I noticed I was shifted over from where I was actually going under the bridge. Various channels and channel depths aren't showing correctly either. I haven't updated the GPS since I got it - over a year now. Would things start to shift and get off track over time? This is my first boat and GPS. I have a navionics chip in it. So do these GPS's need regular updates to stay accurate? Main reason I haven't updated is because it is mounted on the boat. The last couple times I've been out I've seen things that are blatantly wrong so now I am wondering if it is time. Also my unit has a bad connection between the power cable and the unit so it cuts off several times while I am out. I haven't had a chance to try to fix that yet. Just adding that info as it may help someone understand the problem with the inaccurate GPS readings.
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There should be a map offset option somewhere to fix that...
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The GPS Receiver does not need regular updates to keep it accurate. It is either working correctly or not. Have you changed anything on the boat, perhaps moved the GPS Receiver or added something that may now be blocking the satellite signals from getting to the GPS Receiver?
Go to the GPS Diagnostic View and let us know what the readings are for the Fix Type, HDOP and EPE (Estimated Position Error).
Have you always used that same Navionics map card or have you added it or changed to a newer one?
The only way to make things show “off” would be if the GPS Receiver is not tracking the satellites properly, if a new/different map card was used or if you somehow used the Map Offset function as LocDown stated.
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I've always had the same navionics chip and only recently have I noticed that the GPS is off. Also I've never used the map offset feature. Another thing I noticed is some of the trails that show where you have been are actually showing up over land now. Like totally out of whack. I wonder if it is bad that the unit is cutting off when I hit a good sized wave. Can't be good for it. Oh - I haven't installed anything or moved anything that would cause the GPS to act differently.
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Get the readings from the GPS Diagnostic View and we will see if that shows us anything.
Try, very slightly, bending the pins on the power connector away from each other to see if that helps with the power problems.
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Thank you I am going to try bending those pins. I've heard that is a good way to fix that issue. Hope I can get to the bottom of the other issue too.
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Make sure your map datam has not been changed. You should probably be at WGS84..
Chuck