7 ms·
Wow. I wonder how far from the phone this signal could be detected.
by vmarius 6y ago
Wow.
I wonder how far from the phone this signal could be detected.
- fredley 6y agoIt depends on how noisy the surroundings are. In an office block with potentially many other iPhones and sources of interference, probably not far at all. Out in a suburban or rural setting probably much further. I wonder if it'll tune into phone calls?
- erk__ 6y agoHe says in one of the comments that he was able to get a signal you could hear from around 20 feet away.
- m0xte 6y agoI suspect that’s unlikely from my own experiences on this stuff. Perhaps 20-40cm is more likely.
- eptcyka 6y agoIf you are disregarding that detail of the story, why not dismiss the author outright?
- m0xte 6y agoI am disregarding the whole thing. The author knows nothing of EMC. This is expected at close quarters.
- ponker 6y agoWhy would you assume that his experiences and yours are the same?
- m0xte 6y agoIt’s physics. There is EMC testing done on these devices. There is little opinion involved in such matters.
- murgindrag 6y agoYou've clearly never done EMC testing, if you think there's no opinion involved in such matters. You might as well say "It's software engineering. There's no opinion involved..."
- m0xte 6y agoI have, in defence sector.
- murgindrag 6y agoInteresting. I've never done defense. What was it like? In the real world (non-defense), I did this once in my life. We went to and independent testing laboratory (actually the premier / highest-regarded one) with our device. They put it outside, pointed a big antenna at it, and it didn't pass. We made some random changes (adding shielding of some kind somewhere; the lab had it on-hand). Things ... changed. Sometimes they got better. Sometimes they got worse. We didn't know whether we were changing, or simply the radiation patterns to better match the test setup. We kept making tweaks like that until it passed, and that was our final, independently lab-certified product design. If we had tested at a slightly different angle, I'm pretty sure we would not have passed. Or in a different lab. It was deep voodoo. From what the lab guys said, EMC testing almost always looks like that. I believed them. We can't really solve Maxwell's Equations in our head, and we know so little about antenna design that predicting the radiation from a complex device is not really possible. You just tweak, adding a gasket here or ferrite bead or whatever, and pray it works. Most of the small tweaks we did at the lab, but I do recall we did some larger design change (making a signal differential or something) which necessitated going to the lab a second time with a device with a new PCB.
- m0xte 6y ago
- sgt 6y agoJust a few meters, as per the article. I'm guessing if you can't hear it on the iPhone's speaker, it won't be audible on AM radio either.
- m0xte 6y agoCorrect. Although it’s possible on older handsets with 3.5 jack that the audio amplifier in the handset itself is possible to receive. I’m not sure about lightning. But I very much doubt at the stated range. The EMC guys would be all over that.