When I bought my v21, the radio was on inside starboard cuddy wall.

Put my new radio on port dash. Mike mounts on both inside and outside of door.
I like it there because I because I like to leave it on scan, and I can see the channel from anywhere in the cockpit. I can operate it from the helm or my crew can operate it from the port seat. The windshield offers great spray/weather protection, and I keep boat covered when not in use. Besides, the newer radios are more waterproof than the older ones. Far enuff from the compass so that I am sure any interferance is insignificant.