Hi all,

I was recently surprised to learn that, apparently, the U.S. FCC does not
have a requirement for radiated emissions below 30MHz for non-intentional
radiators. There is a conducted emission requirement, and intentional
radiators do have requirements below 30MHz.

Was this a recent change or has it always been this way? As an amateur
radio operator, I always used to marvel at how much consumer gear just
blasts the HF spectrum and I always suspected that it was not tested
properly but now it seems that it is actually legal to sell stuff like that=
!

If this is true, why do people talk about switching power supplies being a
problem for emissions? If it is a line-powered switcher, sure, the
conducted emissions could be a problem, but if you are doing a PCB design
and you are including a 100kHz switching frequency DC-DC converter, it
would seem very unlikely that you would radiate significantly above 30MHz.

Sean
--=20
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.