radio frequency interference

Nothing out of the ordinary is done to Dell's to suppress RFI.  As a matter of fact there are posts from users on this forum with RFI problems.  However, Dell's are manufactured in accordance with FCC requirements for limiting radiating RFI.

RFI can be introduced through the AC power line, from a bad AC power ground or bad internal chassis grounds.  "Cheap quality" parts can be a source as some of the "extras" are not built into these components, including motherboards and  power supplies.  Proper shielding, bypass capacitors, "chokes"  on selected signal and power lines.  Using all metal cases, rather than plastic or part plastic.  Many areas that can potentially allow RFI into the system.   The PC's components must also meet FCC radiation limits both internally and externally and a "home built" or one built by a local PC shop may not meet FCC standards.

thanks for the explanation; now all i have to do is swap out componets one at a time...i hope