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Comment by turtle4 | Hacker News Reader

I can't believe that the demo isn't being run off of its own network. Seriously, if you can't get good reception inside, at least run your own dedicated wifi network. What were they thinking?

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You don't understand WIFI. All WIFI devices share the same 2.4/5GHz bandwidth and thus if you have too many devices in one physical location you're screwed.

Sure, but why didn't they use directional antennas to get a demo-dedicated network on the stage? Which would be a good permanent feature for any big conference room come to think of it.

That doesn't eliminate the problem of interference from all of the other networks on the same channel (or on the neighboring channel that shares part of the spectrum), which are all using omnidirectional antennas. It can help, certainly, but 570 Wi-Fi networks in one ballroom is going to be hell on any network chip trying to sort through all the noise.

Clearly the solution is to stick a Faraday Cage in between the audience and the stage.

Seriously though, I know very little of these matters, but it does seem like there should be some sort of solution developed for them with the frequency that these issues keep cropping up in major tech demos. It seems embarrassing that companies that are supposed to be innovative and great with technology are being stymied by the lack of WiFi.

I am rather surprised that they (seemingly) didn't use a 5GHz 802.11n network. N suffers from some reliability issues as well, but the channels are much more spread out and much less utilized (the MiFi doesn't support it, last I checked), so it theoretically wouldn't have degraded nearly as much if they had used a high-mW antenna to try to cut the distance issues 5GHz suffers from.

Agreed, but 802.11n only works in the 2.4GHz range for iPhone 4: http://www.apple.com/iphone/specs.html

Well... that's useless. How disappointing.

No, I'm including all the antennas in that - why not use directional ones for all the networks in the room to keep the stage free of extra networks?

Because Apple had control over, maybe, 10-20 APs in the room (and those almost certainly only constituted one mesh network). The 569 other networks were from devices controlled by journalists and other attendees, the majority of which were MiFis (according to Jobs), which don't even have ports for external antennas.

There's an antenna in the iPhone too you know...

It's not that simple. The allocated spectrum is saturated so pointing a "loud speaker" at someone is not going to help if they can't hear anything in the first place.

http://news.ycombinator.com/item?id=1411619

There are three channels in 2.4GHz, so presumably Apple could have put Steve on one channel and everybody else on the other two. (This problem is not as bad in 5GHz, but AFAIK the iPhone doesn't support it.)

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