• 0 Posts
  • 202 Comments
Joined 1 year ago
cake
Cake day: February 1st, 2024

help-circle

  • 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.






  • Most of the time that leads to them dying.

    Well, squishing has a 100% chance of them dying. With a toddler and a baby, having them run loose sadly isn’t an option.

    We live in a very mild climate, and there’s under-deck and fence space around our house, in addition to bushes, trees, and underbrush — fairly suitable for a variety of arachnids. It’s not the same as indoors, and survival rate certainly isn’t 100%, but it’s not the death sentence of going from a climate controlled house to below-freezing outdoors.



  • I think large planes “look” like they can’t work because their “relative speed” is really low — that is, their speed relative to their length. We’re used to seeing birds cover tens of lengths per second, whereas a large airliner covers ~1ish per second at takeoff.

    Or not, but this always seemed like a plausible explanation as to why planes look impossible. (Though given that hovering birds don’t look funny, maybe this is a silly observation…).






  • Same — rsync to a pi 3 with a (single) ZFS drive at family’s house. Retain some daily/weekly/monthly snapshots.

    I have a (free) VPS with static IPv4 which is how I connect everything.

    Both the VPS and the remote site have limited network speed (I think 50Mbps for VPS), so the initial sync was done sneakernet (well…“airplane net”). Nightly rsync is no problem bandwidth-wise, and is mostly just any new videos I’ve uploaded to my local Immich instance.


  • I just wish we’d have neither inflation nor deflation.

    Some tech has followed this pattern. For example: entry level Mac laptop in ~2000 was the iBook, priced at $1599 ($3k+ in today’s dollars). The current entry level Mac laptop (M4 Air) starts at $999 — cheaper in absolute dollars, and way cheaper in relative dollars.

    (Macs are just an example since Apple doesn’t have a very extensive product list, so there’s only one “entry level” laptop to choose from. And yes it’s fair to ask if the relative specs have just gotten worse, but I think this is also the opposite — the iBook was iirc criticized as being underpowered, whereas the M4 Air is afaik well regarded.)




  • You mentioned ham radio — definitely fun! It’s a process to get into it though, as you need to study/pass an exam, and then you need a radio. Radios range from cheap ($25 or so) in the VHF/UHF (“walkie talkie”-style) to more expensive for an HF rig ($1000 range for 100W HF). If you want to get into low power (“QRP”) it can be much cheaper. You also need a fair amount of space for a good antenna setup…

    There are tons of different communication modes, some without a computer and, like you mentioned, some that use computers. wsjtx and fldigi are popular programs.

    Good luck!