You would want it to not benear  magentic or metallic surfaces that are nearby. Mine is located under the seat where the hot water heater is closer to the builge.
Haro.

Magnetics and electronics can certainly cause issues that would interfere with the proper operation of your flux gate compass. Locate the device where you will expect to little interference from RF sources, such as your VHF transmitter, GPS chart plotter, and metal objects that can be magnetized. I have mine near the base of the mast.