This might have been better posted to the HAM forum, but it has some amusing cross-over appeal. A plea for help on MacFixIt about a Macintosh that turned off whenever an ICOM two-way radio was keyed elicited a knowledgeable response (same page) that indicated that the problem was actually the display connected to the Mac.

It turns out that some of the older Apple Studio Displays have deficient shielding and are susceptible to stray signals causing them to activate the power button, which then turns off the connected Mac.