Speed variations

Ok I just bought a new boat with all the goodies. Running two 1198's networked with Ipilot link. It's quite an upgrade for me. Took the boat out out last weekend and saw, in my eyes, a huge disparity between my hand held Ilink and my graphs as far a speed. My graphs showed .3 while my I link showed .9. I am now running all the current updates and the receiver is an AS GPR. I am currently in the process with HB to swap out my other receiver with an AS GPS HS. Just looking at the way my fishing line travelled in the water I have to believe my handheld, not the graphs. Just wondering if anyone has come across this yet.

The puck with the heading sensor has known slow speed issues. I haven't read anything about the other puck having low speed issues though.

The difference, 0.6MPH, is less than a foot per second. You can see that much variation in your GPS accuracy, which can cause problems at slow speeds. Bring your speed up to 3MPH and compare them there to make sure it's not a setting issue

Earlier this year when I installed the HS puck, I wanted to push at 0.7 mph. I had at the console an 898 unit with an original puck, at the bow an 898 unit with HS puck, an ipilot remote, and a handheld garmin.

All the units reported me traveling at 0.7 mph except the bow unit connected to the HS puck. I am not the only one that has reported this. I don't argue your statement on GPS accuracy variation, but I do argue that there is something wrong in how the HS puck calculates low speed. Now maybe all the other units are in error and the HS puck is the only one correct, but I doubt this.