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While the world is preparing for 5G mobile technology (which involves new devices for smartphones and stations), SpaceX is going to roll out its Starlink "constellation".

What I did not know is that they are going to provide a WiFi connection (I thought initially maybe they were planning 5G).

Source - screenshot of WiFi via satellite?

Now if Starlink succeeds, will it be a service directly competitive to 5G as such?

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    $\begingroup$ This question is based upon a fake image. Basic questions like "maximum range of WiFi antennas" should be addressed elsewhere, e.g. ElectricalEngineering.SE $\endgroup$ – Everyday Astronaut Apr 3 '18 at 15:39
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    $\begingroup$ Starlink isn't a WiFi network. It can't be received on your phone or laptop. Starlink will require a large receiver which contains a set of phased array antennas. It's most similar current technology is dish based TV and internet; you'll need to mount the starlink receiver outside with a clear view of the sky. Once that's done it'll probably have an Ethernet jack that lets you hook it up to a router. $\endgroup$ – Dragongeek Apr 4 '18 at 13:05
  • $\begingroup$ @Dragongeek Not even the Iridium requires large antennas, although it can get probably a better signal with it. I am sure that there will be StarLink-capable mobile phones, too, just like there are Iridium phones. $\endgroup$ – peterh yesterday
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    $\begingroup$ @peterh Phased array antennas are at the core of Starlink's technology and, currently, putting one in a phone is not really doable. Comparing iridium to starlink also really isn't fair ether as Starlink is designed to have multiple orders of magnitude more clients and internet speeds. Portable phone-sized iridium receivers are not fast enough to browse, they can barely do email and VoIP. Only the large, naval or plane versions approach speeds that are measures in Mbps. $\endgroup$ – Dragongeek yesterday
  • $\begingroup$ @Dragongeek This is super-useful info, thank you. $\endgroup$ – peterh yesterday
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This partial answer is not about the technical possibilities, but about Starlink's hypothetical relationship to 5G.

SpaceX's plans with Starlink are unclear at the moment. On the one hand, one should not expect it to be available in urban areas because it will serve [the] least served. This is obviously reasonable because big cities have the most advanced (and cheapest) infrastructure already. It could mean that Starlink will compete against terrestrial networks in areas where Internet access is more involved (i.e. slow and expensive). So, Starlink will most likely not be an alternative to 5G in places where 5G is set up first.

On the other hand, as was said here, it should help funding SpaceX's development of BFR. That seems somewhat contrary to serving the least served, because usually wealth correlates to some extend with population density (I guess). Elon Musk probably thinks of some compromise by mentioning "sparsely to moderately populated areas". So, Starlink will probably compete with both wireless and wired ISPs in rural to suburban areas.

Rumors say that Starlink might also be one further step to full vertical integration of Tesla.

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    $\begingroup$ I think it would be a nice option for the civil aviation, to provide online internet access on the passanger planes. $\endgroup$ – peterh yesterday
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WiFi from a satellite is actually impossible, due to a number of issues. Regulation wise WiFi only works because of the ability to have low power unlicensed devices, for it to work in space it would require a much more powerful system. The limit is 4 W EIRP. Furthermore, the movement of the satellite will create Doppler shift of the frequency, which will make the bandwidth too high to be supported.

What will actually be done I believe is that each device that wants to use Starlink will use some kind of a dedicated antenna. It might be like an ISP, using an antenna to send internet to a single house, or it might be something broader to send it to something like a Cruise ship, or even ISP to ISP links via satellite.

The frequency of Starlink will be above 10 GHz, well outside of the band of Wifi. At that high frequency, it is possible to have a hand-held device that could receive the satellite signals, as the antenna will be small.

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  • $\begingroup$ Can you give any sources? $\endgroup$ – Steve Linton Apr 3 '18 at 15:36
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    $\begingroup$ There's conflicting information about frequencies (initial application is Ku & Ka, nothing above 10Ghz, but there's discussion of activity above 25Ghz also). One firmly stated thing is that they will not talk to handhelds, instead requiring a pizzabox shaped user terminal to contain the phased array. en.wikipedia.org/wiki/… $\endgroup$ – Saiboogu Apr 3 '18 at 16:26
  • $\begingroup$ @Saiboogu yes there would be a finite number of transponder stations, on roofs or poles, then locally people can implement their own local access one way or the other: youtu.be/ZmEg95wPiVU?t=3000 $\endgroup$ – uhoh 2 days ago
  • $\begingroup$ I think the doppler shift could be compensated with the satellite electronics. And the $\approx$ 8km/s velocity of the satellites likely won't cause too much problem, it is only 0.000026c . An 5GHz wifi signal would get $\approx$ 100kHz deviation due to doppler, while a single Wifi channel is many megabit/sec wide. I see a more serious problem the creation of a directed signal on the mobil phone side. But I don't think that StarLink would use ordinary wifi. $\endgroup$ – peterh yesterday
  • $\begingroup$ It would be extremely difficult to compensate for a large barrage of wide weak signals over a limited bandwith. Starlink won't use Wi-fi, it just can't. $\endgroup$ – PearsonArtPhoto yesterday
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Star link provides high speed internet. The consumer hardware is $200 a pop. This hardware will provide High speed WIFI. High speed WIFI can do anything 5G can do but has less range. Star Link could combine a receiver with a 5G transmitter and thus bypass the Cellular backhaul or provide 5G anywhere they lease the bandwidth. A Ubiquitous LEO communication system could also make it extremely difficult for any country to implement an information firewall. Will E.M. comply with Chinese censorship or dare the Chinese to throw some rocks in front of his toys? OK, yes it would be theoretically possible to add STARLINK reception to a handheld device thus completely bypassing 5G. Thus we would not need HUAWEI!

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    $\begingroup$ How Huawei comes here? All the mobile manufacturers have or will have 5G soon. $\endgroup$ – peterh 2 days ago
  • $\begingroup$ Flagged as political. Yes, that's what political statements read like in our times... :-/ $\endgroup$ – Everyday Astronaut yesterday

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