I have seen people using ferrite beads to suppress EMI from switching power supplies. Recently, I came across the following blog post where the author successfully re-models a switching power supply to reduce EMI noise. At one point, he makes the following comment.
It is common to attempt the use of ferrite beads to suppress RF Interference of this sort, but it's very unlikely that it will help much - particularly at lower frequencies (e.g. lower HF bands such as 160 and 80 meters, not to mention the AM broadcast band) because these devices simply cannot add enough inductance to add a significant amount of impedance: At these frequencies (say, below 10 MHz) it takes multiple turns on a chunk of ferrite to add enough reactance to make even a small dent in the amount of conducted interference!
My question is that whether the author is right or not? I have read that ferrite beads in EMI filtering, acts as a lossy element and turn the RF energy into heat. Did the author forgot to consider this and only considered the high impedance of an inductor at RF? I'm confused as his strategy worked nevertheless