Monitors are the largest source of HF radiation, if of the CRT type, and it mainly comes from the screen. Make sure you have a 3 wire cord properly grounded for the monitor AC. You may also find that chokes on the Monitor video connection to PC helps, and on the AC cord leaving the Monitor. Finally, the screen can be attenuated by the see thru metal mesh shields sold for that purpose. 73, Stuart K5KVH