3 ms·

Digital Telecommunication in HF band - WWWAN - World-Wide Wireless Area Network

65 points by pabs3 3y ago

KaiserPro 3y ago
Related but not quite the same: http://www.dxcluster.org/ http://www.dxcluster.org/ Dxcluster used to use a lot of radio links to disseminate data. However fixed internet lines have become much cheaper, so there isn't the need to have massive HF antenna to create relay link any more.
- runlaszlorun 3y ago
  > so there isn't the need to have massive HF antenna to create relay link any more. HF is having quite a resurgance among various militaries.
  - blantonl 3y ago
    I'm not sure why this was downvoted. The author is correct. Given that space communications and the militarization of space is becoming more and more prevalent, we are on the cusp of seeing some military actions in space that could render a few defense agencies impotent with regards to C3.
greenish_shores 3y ago
"Multimedia"? Over HF where one "cell" (using the WWAN nomenclature) may have several tens kbps of total (uplink and/or downlink) throughput at most? (see Shannon-Hartley theorem, which is distinct from Shannon-Nyquist sampling theorem) But for emails and the rest of proposed use, sure. Also, OsmoDevCon is iirc invite-only, making linking to its schedule on a public forum mostly pointless (visit #osmocom on Libera for more info; disclaimer: I wasn't invited, either). Unless, of course, a recording would be added (which it probably will), but it's not true yet (as the event didn't took place yet?)
- lxgr 3y ago
  If you consider SSB voice one medium, and CW morse code another, HF has been multimedia for more than a century :)
  - nrdgrrrl 3y ago
    There's also SSTV. Surely images, voice and text counts as multi-media?
    - guenthert 3y ago
      Uh, I didn't know SSTV had been used since the Apollo moon landings. But what is it actually used for today? Or is it rather one of those we do, because we can?
- deleted 3y ago
  [deleted]
DeathArrow 3y ago
What HF means in this context? A few GHz? Also, for long range I thought the longer the wave length is, the better.
- SigmundA 3y ago
  https://en.wikipedia.org/wiki/High_frequency https://en.wikipedia.org/wiki/High_frequency
- macnetic 3y ago
  HF is 3 MHz to 30 MHz. Yes it does not make much sense, the term is ancient.
  - nativeit 3y ago
    I mean, any higher and I’ll have to start thinking about printed circuit boards, shielded wires, and non-coat-hanger-based antennas…frankly if 30,000 kilocycles can’t get the job done, I’ll just have to light the thing on fire and use it to make smoke signals. Best regards, 50 years ago
    - xattt 3y ago
      640 K[Hz] ought to be enough for anybody.
  - 1992spacemovie 3y ago
    If you did a modicum of reading it makes sense.
  - yau8edq12i 3y ago
    Ancient? The HF band is still very much in use... Modern developments have not changed the fundamental properties of RF propagation. UHF ("a few GHz") can only be propagated in line of sight reliably. HF can literally travel around the world.
    - lxgr 3y ago
mannyv 3y ago
How is this different from what the ham radio guys have? They were doing ip over ham in the 90s, i think, which is more performant than uucp for sure.
- ale42 3y ago
  Not very different I think... on the air it's the same: they're using VARA, which has been introduced by a ham radio guy (https://rosmodem.wordpress.com/ https://rosmodem.wordpress.com/), and is widely used by ham radio operators. I'm a bit annoyed by the closed and Windows-only nature of VARA (see also discussion https://old.reddit.com/r/amateurradio/comments/12d2s3e/would_you_want_to_help_make_an_open_source_vara/ https://old.reddit.com/r/amateurradio/comments/12d2s3e/would...), but well, it works well as far as I've heard.
DF1PAW 3y ago
Obviously they use this modem: https://github.com/Rhizomatica/mercury https://github.com/Rhizomatica/mercury Any experience with it? How does it compare to VARA oder Pactor?

65 points by pabs3 3y ago

Related but not quite the same: http://www.dxcluster.org/ http://www.dxcluster.org/ Dxcluster used to use a lot of radio links to disseminate data. However fixed internet lines have become much cheaper, so there isn't the need to have massive HF antenna to create relay link any more.

runlaszlorun 3y ago
> so there isn't the need to have massive HF antenna to create relay link any more. HF is having quite a resurgance among various militaries.
- blantonl 3y ago
  I'm not sure why this was downvoted. The author is correct. Given that space communications and the militarization of space is becoming more and more prevalent, we are on the cusp of seeing some military actions in space that could render a few defense agencies impotent with regards to C3.

greenish_shores 3y ago

"Multimedia"? Over HF where one "cell" (using the WWAN nomenclature) may have several tens kbps of total (uplink and/or downlink) throughput at most? (see Shannon-Hartley theorem, which is distinct from Shannon-Nyquist sampling theorem) But for emails and the rest of proposed use, sure. Also, OsmoDevCon is iirc invite-only, making linking to its schedule on a public forum mostly pointless (visit #osmocom on Libera for more info; disclaimer: I wasn't invited, either). Unless, of course, a recording would be added (which it probably will), but it's not true yet (as the event didn't took place yet?)

lxgr 3y ago
If you consider SSB voice one medium, and CW morse code another, HF has been multimedia for more than a century :)
- nrdgrrrl 3y ago
  There's also SSTV. Surely images, voice and text counts as multi-media?
  - guenthert 3y ago
    Uh, I didn't know SSTV had been used since the Apollo moon landings. But what is it actually used for today? Or is it rather one of those we do, because we can?
deleted 3y ago
[deleted]

DeathArrow 3y ago

What HF means in this context? A few GHz? Also, for long range I thought the longer the wave length is, the better.

SigmundA 3y ago
https://en.wikipedia.org/wiki/High_frequency https://en.wikipedia.org/wiki/High_frequency
macnetic 3y ago
HF is 3 MHz to 30 MHz. Yes it does not make much sense, the term is ancient.
- nativeit 3y ago
  I mean, any higher and I’ll have to start thinking about printed circuit boards, shielded wires, and non-coat-hanger-based antennas…frankly if 30,000 kilocycles can’t get the job done, I’ll just have to light the thing on fire and use it to make smoke signals. Best regards, 50 years ago
  - xattt 3y ago
    640 K[Hz] ought to be enough for anybody.
- 1992spacemovie 3y ago
  If you did a modicum of reading it makes sense.
- yau8edq12i 3y ago
  Ancient? The HF band is still very much in use... Modern developments have not changed the fundamental properties of RF propagation. UHF ("a few GHz") can only be propagated in line of sight reliably. HF can literally travel around the world.
  - lxgr 3y ago

mannyv 3y ago

How is this different from what the ham radio guys have? They were doing ip over ham in the 90s, i think, which is more performant than uucp for sure.

ale42 3y ago
Not very different I think... on the air it's the same: they're using VARA, which has been introduced by a ham radio guy (https://rosmodem.wordpress.com/ https://rosmodem.wordpress.com/), and is widely used by ham radio operators. I'm a bit annoyed by the closed and Windows-only nature of VARA (see also discussion https://old.reddit.com/r/amateurradio/comments/12d2s3e/would_you_want_to_help_make_an_open_source_vara/ https://old.reddit.com/r/amateurradio/comments/12d2s3e/would...), but well, it works well as far as I've heard.

DF1PAW 3y ago

Obviously they use this modem: https://github.com/Rhizomatica/mercury https://github.com/Rhizomatica/mercury Any experience with it? How does it compare to VARA oder Pactor?