[mlyle]

We have a standard for the maximum energy on given frequencies, not the total EM emitted. Spread spectrum clocking definitely reduces the peak energy on specific frequencies, which is usually what you care about more.

I guess it makes you more likely to experience interference, but the interference you'll experience, on average, will be much less severe.

[immibis]

No radio receives exactly a single frequency. They all receive a range.

[mlyle]

Sure--- I'm familiar with the bandwidth theorem. In general, a single narrow carrier with lots of energy inside your channel is more harmful to demodulators than spreading the interference over 20MHz, most of which isn't even on top of your channel (or, if your channels are reaaaaaallly wide, it's still just a slightly increased noise floor instead of a strong single frequency swamping your signal).

I've designed a lot of radio systems, built a lot of demodulators, and calculated a lot of link budgets. It's best to assume that people know a fair bit, here, instead of tossing out the simplistic dismissal.

I'm also an amateur radio operator, and I know that strong carriers are often far worse for me down in HF than the same energy spread out over tens of thousands of cycles; though I can often notch carriers, I only have so much dynamic range.