• Tiger_Man_〔he/him〕@lemmy.blahaj.zone
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    16 days ago

    there’s nothing better than optic fiber because nothing can be faster than light

    Edit: as comment below says optic fiber isn’t actually faster, but still better because it has lower packet loss, is cheaper and not owned by elon musk

    • qjkxbmwvz@startrek.website
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      16 days ago

      That’s…not really a cogent argument.

      Satellites connect to ground using radio/microwave (or even laser), all of which are electromagnetic radiation and travel at the speed of light (in vacuum).

      Light in a fiber travels much more slowly than in vacuum — light in fiber travels at around 67% the speed of light in vacuum (depends on the fiber). In contrast, signals through cat7 twisted pair (Ethernet) can be north of 75%, and coaxial cable can be north of 80% (even higher for air dielectric). Note that these are all carrying electromagnetic waves, they’re just a) not in free space and b) generally not optical frequency, so we don’t call them light, but they are still governed by the same equations and limitations.

      If you want to get signals from point A to point B fastest (lowest latency), you don’t use fiber, you probably use microwaves: https://arstechnica.com/information-technology/2016/11/private-microwave-networks-financial-hft/

      Finally, the reason fiber is so good is complicated, but has to do with the fact that “physics bandwidth” tends to care about fractional bandwidth (“delta frequency divided by frequency”), whereas “information bandwidth” cares about absolute bandwidth (“delta frequency”), all else being equal (looking at you, SNR). Fiber uses optical frequencies, which can be hundreds of THz — so a tiny fractional bandwidth is a huge absolute bandwidth.

      • EndlessNightmare@reddthat.com
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        16 days ago

        Light in a fiber travels much more slowly than in vacuum — light in fiber travels at around 67% the speed of light in vacuum

        I’m a complete laymen when it comes to this, but this sounds like it would pertain to latency rather than bandwidth. I expect that fiber would have a much higher data capacity than satellite.

        • qjkxbmwvz@startrek.website
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          16 days ago

          Yep, you’re right — I was just responding to parent’s comment about fiber being best because nothing is faster than light :)

    • Sentau@discuss.tchncs.de
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      16 days ago

      This has got a scary amount of up votes, especially considering that this is the ‘technology’ community.

      Radiowaves are also ‘light’ and infact as many others have mentioned so eloquently, light travelling through air is faster than light travelling through glass. The reasons why fiber is better are - better stability because of lower packet loss and interference, better efficiency because of lower attenuation and losses due to diffusion, reflection, and other processes when traveling in a fiber optic cable, and more bandwidth because we can use more favourable frequencies in optic cables (@[email protected] explains it perfectly in another reply to the parent comment)

    • SkaveRat@discuss.tchncs.de
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      17 days ago

      Light in glass is actually surprisingly slow

      After some distance, starlink would have better latency, as while the signal needs to go through a bunch of km of slow atmosphere, it would make up for that by having a big part of the signal go through vacuum between satellites

      But latency isn’t everything

      Fiber (when properly installed) is very stable. Satellite and mobile is always at least a little bit flaky

      • TonyTonyChopper@mander.xyz
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        17 days ago

        St*rlink orbits at 500 km so you would need to be like 1800 km by land away from your destination to have a better latency. At that point your latency will be terrible anyway

        • SkaveRat@discuss.tchncs.de
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          17 days ago

          Hard to calculate exactly.

          Latency is lower through the atmosphere than in glass (I thought that air was worse, but turns out it’s not. Makes sense. Glass is solid after all)

          So it could be even closer than that. But there’s also the problem of the SL base station having to do the last bit of the route through fiber to the destination again. Do it also depends on where the base station is located in regards to the destination

          • NotMyOldRedditName@lemmy.world
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            17 days ago

            Starlink can be more direct as well. The further fiber goes the less direct it is. By the time we’re talking between continents that builds up a lot.

    • untakenusername@sh.itjust.works
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      17 days ago

      I’ve heard starlink is faster than fiber by a few nanoseconds and big finance really wants that for their high-speed trading

      most of its signals move though space, compared to the glass in fiber so it sorta makes sense