[fsckboy]

I have a feeling this makes charging less... not efficient, but slower charging.

The end of this thing is a bunch of wire in a loop, the inductor that transfers the energy to the phone. So it was odd to me that he chose the cord as the antenna that was broadcasting the noise, when I'd think it would be the business end. These frequencies being broadcast might be overlooked harmonics, ok to filter out, but they might be a designed part of the energy transfer that the charger is attempting. It's possible that he's damped the noise and the charging, but under normal use he doesn't need the maximum charge so it's still a win.

not my specialty, just speculating based on basic EE knowledge.

[ComputerGuru]

It’s not hard to verify before throwing shade at OP’s work. 1) article specifically mentions the actual frequencies used by wireless charging up top, 2) you can refer to Wikipedia to see the same [0]: the frequency for charging is the much lower From 87-205 KILOhertz (while the harmful frequencies being filtered out are in the hundreds of MEGAhertz).

So, no, this doesn’t slow down charging.

[0]: https://en.wikipedia.org/wiki/Inductive_charging