Radar altimeter
Hi
I have been using a TRA3500 on an R44, and would agree with last third's post.
The specs state of FreeFlight
0-100 ft : +-5 ft
100-500 ft : 5%, so 5-25ft
500-2500 ft : 7% so 30-175ft
Flying over the ocean quite a bit last month at different altitudes, I would tend to agree with these figures (most of the time errors are smaller, pe at 1500 ft : 25 ft).
If not over the ocean, then the cone effect indeed exists, but also the effect of delays in the readings, if flying at some speed.
D3