Hi Harry,
I tried to get better fish arches last week, after my arches missed the tail end.
I found out, that if I raise the rear end of the transducer the arches begin to show complete.
If I raise the rear end further up, the front end of the arches start to disappear.
The sensitivity setting is also critical.
Try to adjust the transducer like I described. If you have "full" arches, play around with the sensitivity.
Good luck and best wishes
Harry