Michael Weinstock I'm an amateur (ham) radio operator. The level of background RF noise across the radio frequency spectrum is of specific interest to me. High levels of background RF noise make it much more difficult to establish successful communications with weak signals. When the level of background RF noise is low, even weak signals can be used for radio communications because the signal to noise ratio is acceptable. When the background RF noise level is high, it drowns out weak signals.
I read a very interesting article a few months back where a large number of LED lights were tested side by side for their RFI generation. Frankly, most of the results were abysmal. These devices employ switchmode power supplies which unless carefully designed, produce excessive amounts of RFI all over the radio frequency spectrum.
It is very often the lack of a simple component such as a capacitor that costs a few cents that would have been all that was required to suppress the RF noise.