Good point on shielding the router. Metals boxes and wire mesh for
ventilation are easy to come by.

If I have gear to near to the computer, I can hear a click every two
seconds or so, which I suspect is due to polling on the router, or
communications between the router and the print server.

I have one of those "zap checkers" which indicates RF is being emitted,
though it does not indicate the frequency of the signal. I've seen RF
on the cat5, but haven't bothered to check the boxes.