Quote from: benjamindees on February 04, 2014, 07:38:30 AM

Quote from: MoonShadow on February 03, 2014, 04:47:43 PM

However, a hotspot in space couldn't coordinate timesharing of all the hotspots in it's radio shadow even if it were possible for it to hear them.

You know more about it than I do, but perhaps this is relevant:

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The signal on the ground will be fairly weak, in order to not interfere with local networks. At this time, we're shooting for receive sensitivity of about -90dBm.

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Correct, in all likelihood the noise floor in modern urban areas will be too dense. As much as we would like everyone to use Outernet, it's really meant for people who would otherwise not have access to information.

http://www.reddit.com/r/technology/comments/1wqgmh/outernet_wifi_for_the_world_from_outer_space/cf4nshr

Actually, now that I look, someone also asked this question on their forum. The response seems dubious:

https://discuss.outernet.is/t/can-2-4ghz-even-penetrate-the-atmosphere-efficiently/34

Well, it's either misinformed or deliberately false. I've had my kids look at this site and another site (waterstep.org) to compare the tech claims of one charity asking for money compared to another, and we've largely come to the conclusion that this outer.in site is a scam designed to illicit donations from well intended. As my son noted, the first clue is the "for free" claim. That can never happen. While it might be free to receive, there would still need be advertisments and such. And it's not false that low earth orbit sats have used the S band, but that particular section of the S band is where the attenuation from water is greatest.

EDIT: By "that particular" section of the S band, I mean the sliver of unlicensed bandwidth that B/G wifi occupies. The S band is very wide, but only that portion is unlicensed, and because it's an ISM band (Insustrial, Scientific & Medical) that is used primarily for purposes besides communication. There are other ISM bands, but none that are so wide as the one that B/G wifi (and Bluetooth, and several other short range techs) utilizes. It's that wide because microwave ovens (in particular) use that band due to the fact that the high attenuation of radio waves by hydrogen is useful for heating with radio waves, and microwaves are so paowerful that they produce a lot of 'splatter'. Until wifi came out, it was largely believed that the band was useless for communications due to both the high attenuation and the likelyhood of interfereance from microwaves. Wifi protocols are designed with the likelyhood of occasional interference in mind, however. So is Bluetooth. The rest of the S band experiences attentuation due to water in much the same way that radio does in general, in that the higher the frequency the greater the attenuation from water. Both the US and Russia have massive ultra-low-frequency transmitters, with enormouse power ratings, in order to communicate with submerged submarines via morse code. There are ham radio geeks called "lowfers" who try to communicate in this range as well, but it's hard to do anything when the wavelength of the signal is hundreds of kilometers long. So while there are useful frequencies outside of the wifi band on the S band, they generally require more power for the same task than a lower frequency band such as the L band, and less than higher frequency bands such as the K band. So most of the S band is particularly good for a low power downlink to consumer class receivers, just not within the B/G wifi band.