That's a great question. Maybe contact Airmar about that specific transducer. I have always found them to be very helpful.
If neither can give you a satisfactory answer then you might try this:
1. First, use a hand bearing compass to initially determine how much magnetic disturbance is created by the transducer when it is in operation. When you reach a distance where it no longer affects the compass, you should be safe. Maybe add a bit more just to be on the safe side. I believe the KVH installation manual recommends 3' from another compass.
2. Then, temporarily locate the compass where you want to install it and turn it on. Observe the indicated direction and then energize the transducer. If nothing changes, this should be a safe permanent location.