6 ms·

> safety, and substantially cheaper than a sat phone I agree that it's a really cool project but I personally would not use it as a primary safety mechanism.

> safety, and substantially cheaper than a sat phone I agree that it's a really cool project but I personally would not use it as a primary safety mechanism. I've got a ham radio license and I see the same mistake with people who think a 5W VHF handheld or 10W HF radio will help them in dire straights. HF isn't reliable enough and all it takes is a little terrain to block VHF. You're also not guaranteed that there's even anyone on the other side of the radio if you really need help. I would recommend a SPOT or inReach as a your primary safety device with this as a (neat) backup. All they need is a line of sight to the sky which is much easier to do than either LoRA, VHF or HF. [edit] If you want a good idea of the limits of LoRA Ars did a pretty good write-up a few years ago: https://arstechnica.com/gadgets/2019/10/lostik-usb-lora-radios/ https://arstechnica.com/gadgets/2019/10/lostik-usb-lora-radi... . You'll see that even in a few mile radius there's plenty of places where even a high-end LoRA device drops out because very few radios can go directly through terrain(if you're curious https://en.wikipedia.org/wiki/Through-the-earth_mine_communications https://en.wikipedia.org/wiki/Through-the-earth_mine_communi... covers some aspects). It is a really cool modulation for low power but it's still subject to the physics of radio propagation.

npsimons 6y ago
I'm in mountain rescue and I'll second all of this. It's why we will set up repeaters, or station people as repeaters if we have enough people, but more often than not, we are out of radio communication for hours on end, despite all parties having the necessary equipment. More often than not, we'll use inReach texting to maintain comms. But projects like this excite me for future directions. Sometimes when we've been in areas with cell phone coverage (some wilderness in SoCal has coverage), we will be able to see tracks in SARTopo update live from teams in the field. It's really cool when it works!
- vvanders 6y ago
  Yes! I'm totally 100% on board with this as a secondary data/telemetry mechanism. For all the open source software out there it's a tragedy that there's less of that culture in ham radio(which is one of the primary charters of the spectrum-carve out we have). Stuff like this and the M17 project give me hope that we might some day have something more than just the dumb AX25 packet radios(which are stuck in the 80s at 1200bps and zero FEC).
  - bsder 6y ago
    > Stuff like this and the M17 project give me hope that we might some day have something more than just the dumb AX25 packet radios(which are stuck in the 80s at 1200bps and zero FEC). Isn't there some weird regulation about "non-decipherable" communication holding back usage of Ham bands?
    - adrianpike 6y ago
      Wasn't able to reply when I first saw this, I think because it was too new a comment - posted a long-winded reply as a sibling though, but generally it's not a matter of regulation, just a matter of interested and skilled parties willing to donate their time.
    - vvanders 6y ago
      Not really, as long as you publish a spec and it isn't encrypted(except for some really rare satellite control use cases) it's fair game. The really annoying one is they put symbol rate into law instead of bandwidth so we'll never see above 9.6kpbs in the VHF bands(there was a petition a while back to repeal it but from what I recall a bunch of HF folks though it was going to cause chaos across the bands and I don't think it went anywhere).
  - adrianpike 6y ago
    Not able to reply to the sibling comment from bsder, but yes, encryption is forbidden in the ham bands. What vvanders is talking about, and it's a massive point of frustration for me too, is that all of the layer 2 open standards that have actual use are ancient. Like, we're supposed to feel lucky that we whave ARQ. Ridiculous. It's not really anything to do with encryption or indecipherability, but all about spectral efficiency, and most of that really comes down to coding. I can pop open fldigi and generate a 64QAM signal really easily, but actually coding the data to ship over that pipe starts getting into some pretty arcane territory. Think about just how good a modern cellphone is - 100+ megabit connection in the palm of your hand, competing for spectrum with hundreds or thousands of other devices, with a handset power of less than 1 watt (usually). There's nothing inherently magical about it, it's just not something that there's a lot of FOSS work around. I've been working on deep diving on this a lot lately, I really think there should be more open source libraries around coding, but I have a funny feeling anyone who gets good at this gets snatched up by someone in the 3GPP consortium.
COGlory 6y ago
I think that the mesh aspect of this would be a substantial improvement over VHF/HF radios. I'm sure I'm wrong, but I don't know of anyone that is running a mesh VHF or HF system in the mountains. I always carry my HAM when I'm out, just in case anyone else is, but obviously that's truly local communication and has the downsides that you mention. With a strategically placed mesh network and some solar panels, you could potentially overcome a lot of the downsides of radio because you could target high areas, such as mountain peaks, to help bridge those obstructions. I definitely don't disagree that the #1 safety device is a GPS/sat phone, but those are prohibitively expensive and most people don't have them. If we could get some solar powered radios along ridges, and a decent percentage of people carrying them, I think there could be a very comprehensive mesh network that would work for most needs. Bearspray is already pretty ubiquitous, I don't think it'd be that hard to get people to bring a $30 mesh radio with them as a routine thing.
- vvanders 6y ago
  Take a look at the Ars article, it's really hard to get coverage in moderately flat areas over a reasonable distance(1m+). You also quickly start running into the Hidden Node[1] problem or the N^2 aspect of channel congestion(which is why LoRA has such low throughput). Cell companies spend billions on this and even then you'll still have gaps outside of the metro areas, and they're using much more advanced modulations like CDMA and FDM/TDM with a central coordinator. I've talked with a fair number of people who maintain commercial repeaters in mountain areas and those can be incredibly difficult(combination of hard access in winter, large temperature swings and theft of solar panels/batteries) so which it might be possible, my guess is the level of investment just doesn't pencil out for the usage. [1] https://en.wikipedia.org/wiki/Hidden_node_problem https://en.wikipedia.org/wiki/Hidden_node_problem
  - COGlory 6y ago
    Thanks for the detailed response!
    - vvanders 6y ago
biswaroop 6y ago
Do you know if there's an open source PLB like the inReach?
- vvanders 6y ago
  Not to my knowledge, given that a false activation of a PLB still calls the calvary I'd be hesitant to use something that wasn't extensively tested.
- handedness 6y ago
  Just a side note that InReach/Spot are not PLBs, nor are they sufficient for situations that call for PLBs: https://www.backcountrychronicles.com/delorme-satellite-gps-messenger/ https://www.backcountrychronicles.com/delorme-satellite-gps-... I've carried SPOT/inReach/[Iridum/Globalstar phones] extensively in remote areas, and while they are nice to have for convenient communication, I experienced enough issues with each that I would never rely on them in a life-threatening situation.
handedness 6y ago
> I would recommend a SPOT or inReach as a your primary safety device with this as a (neat) backup. All they need is a line of sight to the sky which is much easier to do than either LoRA, VHF or HF. I have quite a bit of experience with both, and wouldn't recommend either as a primary safety device. PLBs are far better. SPOT is based on Globalstar, which leaves one without coverage in many areas. I also found it to be incredibly flaky even in areas of allegedly great coverage with a totally open sky. inReach is vastly more reliable, and with global coverage, so if I was buying one for a (secondary) safety that would be the easy winner of the two. It also has the added benefit of bringing a convenience that PLBs don't, as one can grab weather updates and easily text others for information. That said, it's not difficult to get into a situation where terrain makes quick satellite acquisition very difficult, and one could wait hours for a message to get out. PLBs are much more reliable in adverse situations (N-S slot canyons), have higher power output than satellite messengers, and are generally built to higher standards. They also don't require a monthly fee. A legitimate PLB would give one more paths to a swift rescue, especially if SAR aircraft are already up and looking for you. More info: https://www.backcountrychronicles.com/delorme-satellite-gps-messenger/ https://www.backcountrychronicles.com/delorme-satellite-gps-...
- jf 6y ago
  What PLB do you recommend? I got an inReach because I was so overwhelmed trying to sort out the various PLB options
  - handedness 6y ago
    The ACR ResQLink View is usually a good default choice. I've read good things about McMurdo, but everyone I know who has need for a PLB carries an ACR, either the older 400 or the newer View, which I would recommend over the 400. But just as an inReach isn't a replacement for a PLB, neither is a PLB a replacement for an inReach. It's great to be able to communicate in emergency (and in many non-emergency) situations.
    - jf 6y ago
      Thank you. I'll be buying an ACR ResQLink View as soon as my budget allows. I appreciate the reply!

npsimons 6y ago

I'm in mountain rescue and I'll second all of this. It's why we will set up repeaters, or station people as repeaters if we have enough people, but more often than not, we are out of radio communication for hours on end, despite all parties having the necessary equipment. More often than not, we'll use inReach texting to maintain comms. But projects like this excite me for future directions. Sometimes when we've been in areas with cell phone coverage (some wilderness in SoCal has coverage), we will be able to see tracks in SARTopo update live from teams in the field. It's really cool when it works!

vvanders 6y ago
Yes! I'm totally 100% on board with this as a secondary data/telemetry mechanism. For all the open source software out there it's a tragedy that there's less of that culture in ham radio(which is one of the primary charters of the spectrum-carve out we have). Stuff like this and the M17 project give me hope that we might some day have something more than just the dumb AX25 packet radios(which are stuck in the 80s at 1200bps and zero FEC).
- bsder 6y ago
  > Stuff like this and the M17 project give me hope that we might some day have something more than just the dumb AX25 packet radios(which are stuck in the 80s at 1200bps and zero FEC). Isn't there some weird regulation about "non-decipherable" communication holding back usage of Ham bands?
  - adrianpike 6y ago
    Wasn't able to reply when I first saw this, I think because it was too new a comment - posted a long-winded reply as a sibling though, but generally it's not a matter of regulation, just a matter of interested and skilled parties willing to donate their time.
  - vvanders 6y ago
    Not really, as long as you publish a spec and it isn't encrypted(except for some really rare satellite control use cases) it's fair game. The really annoying one is they put symbol rate into law instead of bandwidth so we'll never see above 9.6kpbs in the VHF bands(there was a petition a while back to repeal it but from what I recall a bunch of HF folks though it was going to cause chaos across the bands and I don't think it went anywhere).
- adrianpike 6y ago
  Not able to reply to the sibling comment from bsder, but yes, encryption is forbidden in the ham bands. What vvanders is talking about, and it's a massive point of frustration for me too, is that all of the layer 2 open standards that have actual use are ancient. Like, we're supposed to feel lucky that we whave ARQ. Ridiculous. It's not really anything to do with encryption or indecipherability, but all about spectral efficiency, and most of that really comes down to coding. I can pop open fldigi and generate a 64QAM signal really easily, but actually coding the data to ship over that pipe starts getting into some pretty arcane territory. Think about just how good a modern cellphone is - 100+ megabit connection in the palm of your hand, competing for spectrum with hundreds or thousands of other devices, with a handset power of less than 1 watt (usually). There's nothing inherently magical about it, it's just not something that there's a lot of FOSS work around. I've been working on deep diving on this a lot lately, I really think there should be more open source libraries around coding, but I have a funny feeling anyone who gets good at this gets snatched up by someone in the 3GPP consortium.

COGlory 6y ago

I think that the mesh aspect of this would be a substantial improvement over VHF/HF radios. I'm sure I'm wrong, but I don't know of anyone that is running a mesh VHF or HF system in the mountains. I always carry my HAM when I'm out, just in case anyone else is, but obviously that's truly local communication and has the downsides that you mention. With a strategically placed mesh network and some solar panels, you could potentially overcome a lot of the downsides of radio because you could target high areas, such as mountain peaks, to help bridge those obstructions. I definitely don't disagree that the #1 safety device is a GPS/sat phone, but those are prohibitively expensive and most people don't have them. If we could get some solar powered radios along ridges, and a decent percentage of people carrying them, I think there could be a very comprehensive mesh network that would work for most needs. Bearspray is already pretty ubiquitous, I don't think it'd be that hard to get people to bring a $30 mesh radio with them as a routine thing.

vvanders 6y ago
Take a look at the Ars article, it's really hard to get coverage in moderately flat areas over a reasonable distance(1m+). You also quickly start running into the Hidden Node[1] problem or the N^2 aspect of channel congestion(which is why LoRA has such low throughput). Cell companies spend billions on this and even then you'll still have gaps outside of the metro areas, and they're using much more advanced modulations like CDMA and FDM/TDM with a central coordinator. I've talked with a fair number of people who maintain commercial repeaters in mountain areas and those can be incredibly difficult(combination of hard access in winter, large temperature swings and theft of solar panels/batteries) so which it might be possible, my guess is the level of investment just doesn't pencil out for the usage. [1] https://en.wikipedia.org/wiki/Hidden_node_problem https://en.wikipedia.org/wiki/Hidden_node_problem
- COGlory 6y ago
  Thanks for the detailed response!
  - vvanders 6y ago

biswaroop 6y ago

Do you know if there's an open source PLB like the inReach?

vvanders 6y ago
Not to my knowledge, given that a false activation of a PLB still calls the calvary I'd be hesitant to use something that wasn't extensively tested.
handedness 6y ago
Just a side note that InReach/Spot are not PLBs, nor are they sufficient for situations that call for PLBs: https://www.backcountrychronicles.com/delorme-satellite-gps-messenger/ https://www.backcountrychronicles.com/delorme-satellite-gps-... I've carried SPOT/inReach/[Iridum/Globalstar phones] extensively in remote areas, and while they are nice to have for convenient communication, I experienced enough issues with each that I would never rely on them in a life-threatening situation.

handedness 6y ago

> I would recommend a SPOT or inReach as a your primary safety device with this as a (neat) backup. All they need is a line of sight to the sky which is much easier to do than either LoRA, VHF or HF. I have quite a bit of experience with both, and wouldn't recommend either as a primary safety device. PLBs are far better. SPOT is based on Globalstar, which leaves one without coverage in many areas. I also found it to be incredibly flaky even in areas of allegedly great coverage with a totally open sky. inReach is vastly more reliable, and with global coverage, so if I was buying one for a (secondary) safety that would be the easy winner of the two. It also has the added benefit of bringing a convenience that PLBs don't, as one can grab weather updates and easily text others for information. That said, it's not difficult to get into a situation where terrain makes quick satellite acquisition very difficult, and one could wait hours for a message to get out. PLBs are much more reliable in adverse situations (N-S slot canyons), have higher power output than satellite messengers, and are generally built to higher standards. They also don't require a monthly fee. A legitimate PLB would give one more paths to a swift rescue, especially if SAR aircraft are already up and looking for you. More info: https://www.backcountrychronicles.com/delorme-satellite-gps-messenger/ https://www.backcountrychronicles.com/delorme-satellite-gps-...

jf 6y ago
What PLB do you recommend? I got an inReach because I was so overwhelmed trying to sort out the various PLB options
- handedness 6y ago
  The ACR ResQLink View is usually a good default choice. I've read good things about McMurdo, but everyone I know who has need for a PLB carries an ACR, either the older 400 or the newer View, which I would recommend over the 400. But just as an inReach isn't a replacement for a PLB, neither is a PLB a replacement for an inReach. It's great to be able to communicate in emergency (and in many non-emergency) situations.
  - jf 6y ago
    Thank you. I'll be buying an ACR ResQLink View as soon as my budget allows. I appreciate the reply!