Loss of H20c Accuracy

[Genofish]

I have been using my Lake Master MN chip in my H20C and lms332c for the past 2 years with great accuracy. Last week i was on my "home" lake and the H20c map showed i was ontop of a island but when i drilled my hole i was off to the side in 22' of water. The EPE was 22' but i was more like 55' off of position. This is the first time i either unit has been so far off. I verified all of the settings but cant find anything that was changed. Any ideas guys?

[Ralph Wiggum]

Has your GPS+Lakemaster chip put you on top of this island before? Is it a survey lake, or just the enhanced DNR map? I would bet that it is not your GPS that is off, but the map is not entirely accurate.

[ChuckN]

I've seen the same thing, and the EPE is probably not the most accurate either, but weather can mess with these units. Seems like really high barometric pressure really throws mine out of wack.

[Chuckster]

I have had the same problems except mine is when I am using my Navionics chip. I have been off a few times by about 30 ft or so as far as finding a breakline, hump, structure, etc. Is this my unit or is it the Nav chip? I noticed that on the larger lakes it is very accurate but as far as using it on a smaller lake it can be off. I figure at least it is putting me close, but it would be nice to be within a foot or two.

[Ralph Wiggum]

I'd bet it's the map. Those lakes likely aren't surveyed, so they're not too accurate.

[Powerstroke]

I have a Magellan Medidian Plat and I don't ahve the advantage of using the chips, but in general, using the mapping abilities can be tough when you're GPS is showing EPE.....

I don't even remember what those initials really mean, but I know on mine if I'm getting EPE it means I've only got 3 or 4 satillites. If I can get more than that it will go to "averaging" which usually puts you in the ballpark or within 30ft. If I can get WAAS, then I'm 98% of the time within 5 feet of where I thought I was.

Sometimes the GPS is out of whack all on its own depending on its signals. Nine times out of ten my "track" lines follow the highway I am on, every once and a while there will be one line way off to the side for no good reason. If I knew I would share it.

Only thing I can think of is to try and recalibrating your GPS. I did a re-setup from scratch and it seemed to help when I started having problems.