I was advised to do this years ago, and leave the radar on standby.
Being of a curious nature, I've opened up the nose bay and seen first hand what happens to the radar scanner plate when the aircraft is de-powered from the standby setting; it gently drops onto the lower extremity of it's travel. Having then checked how easy it is to move it in the vertical sense when unpowered, I'm sure it would "bounce" off the bottom stop during ground taxying.
(Our maintenance company also power up the aircraft gyros before towing it, or, I believe, alternatively wait thirty minutes after they were last switched off, so they are fully wound down; I str that one's a maintenance manual requirement).