"Interesting - with the LSS the lines are caused by a harmonic with the downscan beam where it overlaps - this appears to be the same situation. However, just outside this slightly dead area is a band of enhanced ensonification, where the downscan and sidescan beams actually appear to add to each other. It is in this small band that I have found maximum substrate penetration takes place - revealing objects buried below the visible substrate. From an aesthetic point of view it's pants. From a practical point of view it's actually quite useful."
Sounds very exciting and you must be extremely clever, but it means absolutely nothing to me.
Sorry Trevor.