gps accuracy - Lowrance

slapshotjh · 05-26-2009, 09:31 AM

I have a Lowrance LCX-110C, 3-4 years old and discontinued. It has the puck style GPS antenna mounted on the t-top. Not much else up there, just a hailer a few feet away and the all-around navigation light.

This season, I have noticed that the accuracy of the GPS is worse than I remember. I tried fishing some small pieces of structure I have marked, and they weren't exactly where I left them last season. The unit will display EPE (which I think is position error), and it is up around 40 feet this year. When the unit was new, the position error was lower around 10-15 feet and finding rocks and ledges was easy once they were marked.

Is this something that can be recalibrated, or are the government sattelites off this much? I know the structure didn't move.

Butch Davis · 05-26-2009, 04:18 PM

I have the 111C which, I believe, is your unit plus a hard drive.

If it has remained off for a few weeks it can take quite a while to get all the sats plus the WAAS for the first time. It may be that your WAAS is not turned on. Something else that may help is for you to enter your position upon startup. In order to speed up the sat acquisition process I turn my unit on at home before proceeding to the ramp. This gives it the opportunity to fully acquire all the sats before launching. I have noticed that my EPE improves as the day goes on. About the best I see is eight feet. As my boat is only 16 feet thats about as good as it gets. It can take quite a while to get the eight foot EPE but it always gets there.

larrynimmo · 05-26-2009, 05:24 PM

your gps info is sent by the puck...if its not accurate, problems may be with the puck...(what the puck?)...not again.

pastaman1234 · 05-26-2009, 06:05 PM

If you are marking structure by drifting over it and then marking the spot on your gps not only are you contending with a 40' or whatever position error that day you also have to add the distance between your ducer and gps puck. Haveing your puck as close to the ducer as possible will help close the gap. My puck is on my transom directly above my transducer. Something to think about.

saltfever · 05-26-2009, 06:14 PM

We have had the 104-C unit since 2004 and it has always been on target.

slapshotjh · 05-27-2009, 06:46 AM

I guess I'll have to check to see if WAAS is turned on. I start it up in the slip while the boat is warming up, and it usually locks on inside of 30 seconds. The EPE actually seems to get higher (less accurate) as the day goes on. I haven't bothered to look to see how many satellites it is acquiring yet.

slapshotjh · 05-31-2009, 01:40 PM

I used my machine today. The only options I have related to WAAS are to "require WAAS" or to turn on WAAS alarm. I watched the machine, and noted that WAAS comes and goes all the time. If you select "require WAAS", it drops out all the time when WAAS goes down. On the status page, it appeared to be seeing quite a few sattelites. Is my GPS antenna failing?

Kerry · 06-01-2009, 01:59 AM

No the GPS antenna appears ok and doing exactly what it has been told to do. “Require WAAS” would indicate that if there are no WAAS corrections then there will be no position at all, it is “requiring WAAS”. WAAS is a highly overrated system for terrestrial use with the geo satellites over the equator and it appears your location might have a low (intermittent) visibility of the WAAS satellites hence the dropping out all the time AND no position BUT still normal GPS sats in view.

Best thing to do is get rid of WAAS but then I heard a rumour that some Lowrance models do not alloy the user to turn WAAS off and if so this would have to be one of the most dumbest forced configurations any manufacturer has ever invented.