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#21
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Starlink Satellites Observed
On 2020-04-26 12:32 PM, JF Mezei wrote:
On 2020-04-26 11:20, David Spain wrote: uniform. It will have to make routing decisions based on load. YMMV when it comes to latency. The constantly changing routing decisions are what will really impair the service, especially for stock trading as this introduces jitter (constantly changing latency). Stock trading lends to some seriously funky network topology. I've heard some wild stories about networking companies routing traffic through spools of fiber optic cable in order to lawfully keep local traders from having unfair advantages over distant ones. There a technical term traders use for this gaming of the system. I can't recall what it is. (Front running the market?) It isn't a new concept. Also, a "router" itself introduced latency not only because of the time to process a packet (make routing decisions and send it to appropriate interface) but also because it needs to fully receive a packet before processing it, as opposed to a repeated that is an analogue device that blindly repeats analogue pulses without trying to understand or process them. I've worked with this gear and written design verification tests for it. You are being wildly pessimistic about the speed of this gear. Even the power restricted gear that sits in a satellite. You are talking minuscule decimal fractions of a millisecond worse case. Constantly changing connections also introduce a lot of data overhead because each router need so contanrtly update its routing tables to know which satellite ad ground stataion is availab;e to its interfaces. See above. The processors in this gear cycle in picoseconds. Once you have satellite to satellite links, that satellite over London will have route back down to the london ground station to pickup traditional Internet to New York, and will have routes via multiple hops across satellites to one which is above New York and then use that one to connect to a new york ground station. There is logic in routing algorithms to "prefer" certain routes/providers over others. Yes, but the same is true for terrestrial connections. Not sure I follow your argument here. I'm not trying to be a SpaceX fanboy, but thanks to Jeff's link I think I have a better understanding of how the Starlink topology works and for sat-to-sat it appears to be reasonably competitive. Dave |
#22
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Starlink Satellites Observed
On 2020-04-26 1:57 PM, JF Mezei wrote:
On 2020-04-26 13:07, David Spain wrote: Rural cell towers are well over 100ft in height, some of the ones I've seen. If 5G is line of sight, that's a goodly line. But the common freqs. probably will be the ones you say. 5G is NOT millimetre wave. 5G will be deployed on conventional frequencioes first. The mmwave stuff is just lobby hype to make it look essential for survival of ecomnomy for carrierts to be allowed to install antennas for free and without eavy regulatory burden on urban furniture. IDNST. I'm providing an instance where mmwave could span longer distances. Obviously 5G and mmave are not the same and I said as much by agreeing that lower freqs. will be the more common ones. Why are you putting words in my mouth? I think you are being overly pessimistic. I WAS a user of GEO sat on the Ku band so I don't have to speculate. Rain fade was extremely occasional. Heavy web snow will also kill it, and will accumulate and stick to antennas. You saw what I said about that based on real experience. Not a significant issue. But go ahead and imagine otherwise. It had to be raining pretty darned hard to kill it. Average thunderstorm will kill it. Not for long, but will kill it. Depends on where that thunderstorm is relative to the position of the sat in the sky. Not every storm did for me. To say "average" doesn't make sense to me. Also a factor to consider you don't mention, and that is multiple sats are visible to Starlink pizza box at once. That wasn't true of my GEO Ku band setup which was aimed at a spot target. How badly do storms effect GPS? Might be a better comparison than to GEO sats. BTW my GEO set up also suffered from solar glare twice a year for about 20 minutes each time as the sun passed behind the sat and obscured its signal. That won't be a problem with Starlink. Dave |
#23
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Starlink Satellites Observed
In article ,
says... On 2020-04-25 18:39, Jeff Findley wrote: In the interim, the beta testers/customers that are within range of a Starlink satellite to ground station hop will "just" have satellite Internet that has lower latency than regular GEO satellite Internet. Everything will beat GEO Internet service. And there is your primary business case right there. But if Starlink wants to proide Starlink service in Canada's acrtic, it will need to build a ground station there, and that ground station will need to use GEO satellites to link the ground station to the Internet. Hell of a lot less customers in Canada's Arctic than there are in the continental US. Starlink will no doubt focus on the most profitable markets first. Some of those markets simply do not need crosslinks. The one thing LEO constellations share with LEO is the uplink capacity limits which is limited by the spectrum they are allowed to use betwen satellites and ground stations. We shall see. But do note that since the satellites are much lower than GEO, it takes a lot less power for a ground station to transmit to them. The equations are not as simple as one would hope. https://www.electronicdesign.com/tec...ns/article/217 96484/understanding-wireless-range-calculations The more ground stations you have (with focused beams for GEO or just limited line of sight for LEO) the more capacity you have. SpaceX may be able to launch thousands pizza boxes for free, but it still has to deploy a high number of gound stations, each providing adequante connectivity to the Internet. Still orders of magnitude less ground stations than the number of 5G towers needed to widely deploy 5G. This is why 5G won't be serving very many rural customers (i.e. potential Starlink customers). But if you wish to serve a farmer in Otumwah IOWA, you may have your Chicago ground station that is in range. But Otumwah, if it doesn't already have FTTH or even DSL, is likely to have cellular. So much of the footprint aorund a ground station may already have service. Not 5G cellular in the sticks. Again, I know people that live "out there" and they're lucky if they have DSL which isn't sufficient for me working from home like I am now. And once you have inter-satellite links, the more satellites are aggregated into one that as sight of a ground station, the less capacity you have per user. This is bull****. LEO solves latency, not capacity. This is also bull**** when you compare to GEO service. Look at the equation of RF power over distance. Look at the exponent on distance. Jeff -- All opinions posted by me on Usenet News are mine, and mine alone. These posts do not reflect the opinions of my family, friends, employer, or any organization that I am a member of. |
#24
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Starlink Satellites Observed
In article , says...
There were also at that time daily download caps there were severe. I can't recall now exactly what it was but it was laughable by today's standards. Something on the order of 300MB or so. This is why my remote co-worker had to go to the office to do downloads of the once every other week "full" builds. Those, at the time, were typically 100 GB. These days, it's more than double that. The daily incremental builds are smaller, but still measured in tens of GB. Jeff -- All opinions posted by me on Usenet News are mine, and mine alone. These posts do not reflect the opinions of my family, friends, employer, or any organization that I am a member of. |
#25
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Starlink Satellites Observed
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#26
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Starlink Satellites Observed
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#28
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Starlink Satellites Observed
Let's try that again:
On 2020-04-30 11:32 AM, Jeff Findley wrote: My mom lives out in the country.Â* She's stuck with crappy DSL and very marginal cell phone coverage for my carrier.It's like being stuck in a data desert when I visit.Â* My smart phone is pretty much uselessthere. Jeff In article , says... On 2020-04-30 11:32, Jeff Findley wrote: The problem is not 5G technology as much as the fact that the mobile companies don't profit as much from upgrades to infrastructure in rural areas Upgrading an existng radio to the next generation does not cost that much, and it allows the carriers to streamline site management to the same software. The new generation (5G in this case) has better compression so gives more capacity for same amount of spectrum. So it is to the advantage of the carrier to upgrade. This is not the same as adding more cell sites. I am talking about upgrading existing ones. Then why is my cell reception absolute crap in the country if it's so cheap to implement high power high bandwidth towers in rural areas? Answer: $$$$ Jeff Yes, but there is one other consideration. Not all cell carriers are equal in where they choose to provide service. My old hometown is not well served by the carrier I use for my smartphone at home, in a completely different state. But were I to switch carriers, I would have seen a vast improvement. Jeff, the same might be true for where your mom lives. Or not. Just saying it is a consideration. YMMV. Dave |
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