I have a 788 ci HD, and the gps on my unit is jumpy at best too, and I get the donut/red circle when longlining at .5mph up to .9mph. The mph is seldom steady when compared to a garmin HH, which matches my Ipilot 99.99% of the time. I've gotten the donut from day one, and have the latest update, X.250 I think. Dont remember the "X" number.

How much "clearance" does the HB units with internal antennas need to lock in.


About 2 weeks ago, it took my 788 about 10 minutes or so to lock on, and still had the donut.