[Dylan16807]

> They can't. "It looks like noise" isn't a metaphor, it's a mathematical truth... it is indistinguishable from noise.

That's a bold statement.

Encryption makes the bits look like noise, but you still have to turn bits into signals, and that has structure.

Efficient signaling methods look a lot like noise, but any safety margin makes it distinguishable from noise.

Beyond that, increases in noise in specific bands are still a notable event.

Even if it's spread across many or all bands, what is causing that.

Only highly directional signals would be hidden from us.

And of course transmissions might be too weak to see, but that is not what we're talking about here with the type of signal.