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Comment by blackoil | Hacker News Reader

Satellite can't beat bandwidth or latency of a cell tower in neighborhood connected to fiber connected to edge node few km away.

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Yeah, I think the market they're ultimately going for here is to stop having to roll out cell towers to areas where there's low population density, like rural areas, the mountain west, stuff like that. In cities, it'll always be more efficient for any given set of EM spectrum technologies to use small installed antennas within a few 100m of you than it'll be to push the same link over 500km.

No but theoretical round-trip times are getting pretty dang short as these sats are launched into lower and lower orbits.

The round-trip speed of light to a geosync orbit is 239ms, but some of these LEO sats are already sitting as close as a 4ms round-trip away, and there have been proposals for some even closer.

Have worked on "closer", think on the order of half of that.

Yet, https://physicsworld.com/a/alpine-adaptive-optics-experiment....

I really don't understand the first paragraph,

> Researchers in Switzerland have transmitted and received optical data at rates of more than 10 Tbit/s between an Alpine peak and an observatory at the University of Bern – a distance of 53 kilometres. This is more than five times further than would be needed to set up a satellite-to-ground communication link

Google says Starlink satellites are 550km in altitude... Is this to do with turbulence below 10km?

Not turbulence, air density. Oxygen molecules, dust/pollution, weather.... all of that attenuates light and RF.

Makes sense, thanks.

But most people don't know that. Not yet at least.

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