Well I am not convinced that the GPS is jumping spots, and not keeping track of time. I have done another power dive test with it, this time with no wind (Nice day that day), and according to the GPS, I was doing 137 MPH. 5 MPH difference between windy and calm I would guess is acceptable.
I have used this GPS on a 14 hour car ride, and it was flawless. on my way home, when zooming in, on the track display It wold show me I was on the other side of the road than on my way up, and it showed the MAX MPH accurate to my actual max speed.
I also tested the GPS pointing the antenna to the ground, and it never lost signal over a 2 minute period.
Has anyone else tried to strap their GPS to an aircraft and checked speed?