I'm not an expert. That's rather the point.

There's no name on this site, and there doesn't need to be one. What I am is the person the technology is actually sold to — someone who buys the phone, plugs in the router, accepts the update, and then spends the next week quietly wondering what just happened.

I don't have a lab, a spectrum analyser, or a friend at a chip company. What I have is a question that won't go away, an afternoon, and enough stubbornness to read the documentation nobody reads. That turns out to be enough more often than you'd think.

So that's what this is. One question per post: what I wondered, what I found, and what turned out to be wrong. If the answer is boring, I'll say it's boring. If I couldn't find it, I'll say that too — an honest dead end is more useful than a confident guess.

Anonymous because it shouldn't matter who's asking. Either the answer holds up on its own or it doesn't.