>>"a.4. Specially designed or modified to reduce the compromising >>emanations of information-bearing signals beyond what is necessary >>for the health, safety or electromagnetic interference standards;" >So, who gets to say what's a standard? >Some people's standards are higher than the government >(e.g., varieties of 'organic'; kosher; etc). This is especially true for radio amateurs (hams) doing "weak-signal" work on the VHF (30-300 MHz) and UHF (300-3000 MHz) bands. Some of the propagation modes used include tropospheric scatter; meteor trail reflection; satellite communications; and the ultimate, EME (earth-moon-earth, i.e., using the moon as a passive reflector). Natural background and modern receiver noise levels are all very low on these bands, so unwanted computer emissions have long been a serious problem. (Modern CPU clock speeds are now well into the UHF region). Simply meeting the FCC Class B (residential) emission limits is not nearly enough. Those regulations were intended to protect broadcast receivers working with signals considerably stronger than those involved in amateur weak-signal work. So ever since the first personal computer appeared in a ham shack, hams have been trying to shield, bypass and otherwise suppress their interfering signals. Some approaches resemble those taken in Tempest equipment: special filters on power and signal lines; metal equipment cases with insulating paint removed and resealed with finger stock and copper tape; plastic cases coated with conductive paint; and so forth. I still have an early-80's clone monochrome PC monitor that I extensively modified in this way. It's obsolete, but it's quiet. And it was all "necessary for (my) electromagnetic interference standards". Phil
