Ham radio (or amateur radio) operators have historically filled this role - providing essential communications in the event of a disaster.
I wonder whether this project (if it's successful) would indicate that their numbers have declined past an inflection point, where their presence and availability is no longer assumed.
This won't replace HAM radio in a disaster scenario. This might provide a long-distance digital comms capability post-disaster. Even then, LoRa throughput is so low that I don't see how it would be useful unless an entire region goes full zombie apocalypse and this network replaces... I don't know, messenger pigeons?
In a long range configuration, LoRa has a theoretical max throughput of about 140bps (bits) and that's assuming only one device is transmitting and no packet loss.
LoRa is built for low power, long range, low throughput sensor networks. It's not really suitable for a chatty mesh network. To get an idea of the intended use for it, take a look at LoRaWAN limits:
* An average of 30 seconds uplink time on air, per day, per device.
* At most 10 downlink messages per day, including the ACKs for confirmed uplinks.
* A good goal is to keep the application payload under 12 bytes, and the interval between messages at least several minutes.
This seems to check out. Given 1TB micro SD cards, a card weight of 2.55 grams each, a carrier pigeon being able to hold 75 grams, and the unrealistic but good enough assumption of no further weight being carried (e.g. tape or something else to keep everything from falling off the pigeon), we get 75 / 2.55 = 29.4117647059 (or 29 even taking the floor, since it doesn't make much sense for a pigeon to carry a partial card).
All these numbers are from google summaries, without further source checking.
In a long range configuration, LoRa has a theoretical max throughput of about 140bps (bits) and that's assuming only one device is transmitting and no packet loss.
If you already carry 39 bps of information efficiently by 39 bps actual bitstream, it's not losslesly compressible. That's by definition. Not even by zstd :)
That's the bitrate of a codec to transmit speech that humans can hear and understand... but the actual rate of data communicated by speech is about 39 bps -- and that's pretty universal, regardless of language:
how is this number useful or comparable to digital codecs that are being discussed here? It's an interesting piece of research sure, but I don't see the relevance
Because voice comms are typically used by hams in disaster response -- you pointed out that LoRa tops out at 140 bits, so I responded that that's still 3X faster than voice.
As explained above, the most efficient voice codecs still need orders of magnitude more than that.
This magical 39 bit codec doesn't exist and probably won't ever exist. Even if it did exist, it loses information like timing, identity of the speaker (how they sound), and their tone. By the time you encode all of that, you'll be right back around the range of dmr. And if you're willing to discard all that, then just use digital text in the first place.
I didn't say it was speech, I was comparing the 140bps data rate mentioned by the parent poster with the 39bps data rate from human speech, and pointing out that even 140bps is well above the data rate possible with plain speech.
Any increase in effective data rate of speech afforded by Q codes can also be used to increase the data rate of data transmission.
And as people keep pointing out, the 39bps figure does not refer to speech. It only refers to a single component of speech, which is the syllables being spoken.
When people are talking, they're exchanging far more information than that at a far higher information density rate. Which is why everyone keeps telling you that what you're talking about is not really speech.
The study you linked is focused on linguistics and the effective 'symbol rate' of various spoken languages, by taking syllables spoken per minute and dividing that by the total number of possible syllables in each language.
It says nothing about how much information is actually exchanged between individuals doing the speaking. It doesn't factor tone, accent, pronunciation, mood, pacing, etc all of which are critical components of spoken communication and add up to a lot more than 39bps.
So when you say 'speech is 39bps and this thing does more (it mostly doesn't), therefore this thing is better than speech'. People keep telling that no speech is not actually 39bps and what you're talking about is identical to just written text in this context.
Only of you downsample to text. The inflection, tone and manner of speaking convey huge amounts of data, reguardless of how much is used for framing. This is to ignore facial expression, gesticulation, and posture, which are also part amd parcel of human speech, phones be damned.
Sure (well, I'm not sure I'd say it's "huge" amounts of data, but there's definitely some non-verbal information embedded in speech) but this is disaster communications, not a newscast, I don't want to try to read subtle emotions from tone of voice, I want information -- if the sender is feeling anxious about something, I want him to tell me, I don't want to try to guess how bad conditions are because his voice was a little shaky.
That's the rate that's important. Human speech is sent and received by humans, if you're going to send computer generated speech faster than that (faster than a human can comprehend) and decode on the other end by computer, why use speech at all?
The SX1276 will do 9380 bps at its lowest sensitivity, so it could be boosted, depending on range. FSK mode will go much faster. I wonder if these disaster radios will auto negotiate rates.
All it takes is a couple of lowly hams with mobile radios to cover a huge area...in practice during recent emergencies here in rural norcal, ham radio was really useful, for updates on general news, determining the status of communities around the county, passing messages, and fire spotting. Some of those guys driving up to hilltops were putting their lives at risk so the rest of us could benefit.
We practice every week, so everybody who is an active ham knows the local frequency and they know that there will be updates every hour on the hour.
On top of that, the local WIN System repeater (Western Intertie Network, check their website) was up on backup power, meaning I could have used my walkie-talkie-type radio to get help from distant places like Ireland or Hawaii, if it would have been useful. To say nothing of the amateur radio satellites and HF operation.
One of our local nets during the emergency was a tech-talk net, with about 41 check-ins, all but one on emergency power, when the usual is about 7-12 people. The time was used to discuss lessons learned and one ham is an expert with generators and warned everybody: Change the oil every few days if you are running 24/7. A lot of people were surprised to hear that. And many of them only had one generator to burn through.
To give another example of the usefulness: Imagine, your power goes out, and a day passes without anything exciting happening, so you take a nap, forgetting that the reason the power is out is actually high fire risk.
In a few minutes you wake to a phone call. Your ham radio friend tells you he just heard on the radio a wildfire started a few miles north of your community. This is not on Facebook, it's not anything your neighbors know about.
So you have no idea what to do but fortunately they keep calling with updates from the radio. Eventually they call and give you the all clear and let you know your evacuation warning was lifted, so you don't have to take whatever you can and leave town with your family, spending money and using every last nerve you have just to figure out the next 24 hours.
This is just one specific example that happened here. Everybody else would have warning via text if they were lucky (had battery, tower connection, and proper system configuration), and final warning via a sheriff's vehicle siren if that didn't get through to them. In this case the person receiving calls never got a single text message.
This highlights a critical element of emergency notifications and response: you have to have a plan for how to deal with warnings and alerts. If you don't, then the alert is worthless.
It may even be worse than useless by throwing an otherwise orderly and predictable population into a panic.
How you respond to an emergency, in general, is to reduce risks and consequences. This may mean moving out of the area, but more generally, it means moving out of immediate harm's way. In the event of an earthquake, that can simply be to more out of range of falling debris, or into a solidly-constructed building. For a tsunami, gaining elevation on a secure base (terrain, a very solidly-constructed building). And, of course, responding to changing circumstances and conditions as appropriate.
For widespread disasters -- hurricane and wildfires -- exiting the region or moving to a location that's unlikely to be overwhelmed by the forces at play, is helpful.
For high wind, rain, cold, heat, etc., the challenges often play out over a longer period of time.
Disaster response as with security risks should revolve around threat models. What are the foreseeable threats, what are their specific mechanisms of action (e.g., fire, smoke, heat, wind, flood, ground movement), what's the effected range, and how can the hazards be reduced, mitigated, or countered?
Then there are the long-term survival needs: water, food, shelter, transport, injury and health treatment. Ultimately, rebuilding or relocation.
In one of the biggest disasters of all time, the Bianqao hydroelectric dam collapse following the intersection of a tropical storm and a cold-weather front, about 30,000 deaths were the immediate result of flooding. Another 150,000 or more resulted over the ensuing days and weeks from disease and starvation given both the disruption to ordinary life and the inability to move rescue, recovery, and relief personnel and supplies into the affected area.
None of which has an immediate relation to the ham vs. mesh-network radio debate, but calls into consideration that each are only a small part of an overall disaster response plan.
Be assured that the Amateur Radio community is quite active; especially regarding emergency communication and disaster preparedness.
Personally, I am active with the Connecticut Amateur Radio Emergency Services(CT-ARES), which is a local organization part of the larger national ARES organization(http://www.arrl.org/ares). Both of these offer training and procedures for facilitating communication during emergencies. CT-ARES works with the state of CT, in particular the Red Cross and many local town governments.
My activities include participating in regular 'nets' (http://www.ctares.org/networks.php) which are station tests which serve to prove that my radios work in various failure scenarios. Other members are even more active and practice their communication skills by offering supplemental communication for various events like marathons, fairs, etc.
It comes down to this; you don't know something works unless you regularly use it.
de K2CHA
PS: One should also test their backups by actually restoring from them...
Thanks for the assurance! My grandfather was a lifelong ham (KJ6NK) and I have many fond memories of sitting with him in his radio room while he participated in various nets or picked up QSOs.
I think that depends a lot on the area and local clubs, some are better than others.
While this looks interesting I'm curious if they've done the numbers for Lora throughput. It's very, very low(which is also what makes it able to punch through everything).
Honestly I'm surprised they're not going for a p2p directional wifi. You've got a lot more hardware to choose from(pretty much all WISP hardware) and it has much better throughput with the benefit of dedicated links. Anything that's omnidirectional is going to have to deal with collisions which is not an easy thing to do.
Using LoRa and going omni-directional lets you get away with less upfront setup and a sparser node coverage. Point to point requires some knowledge of node locations for bringing more areas online.
Numbers have dropped a substantial amount in recent years but there are new people getting certified all the time. The cost of hardware keeps going down too. As a HAM its bad for me to get down in these guys for making an effort to produce a product for disaster readiness but...I think the common place FRS radio sets available in every big box store for less than 30 dollars are a more practical tool that everyone should own. CQ CQ CQ VE7 xray mike lima!!!
VE7XLM de KM6NHH. Good point on the FRS. I'm helping coordinate a local neighborhood FRS net here and we are looking at setting up a wider-area GMRS repeater as well; we just had the hilltop location offered by another ham and ran some tests.
BTW my recent emergency experience is documented here:
I happy to see you got a chance to put your tools/experience to good use helping people. It's horrible what is going on down there with the fires and power situation. I decided to get my license as something to do with my Father, a local club(Delta Amateur Radio Society) was offering a ten week course. I was very surprised at how technical the course and subsequent exam was, I have since moved out to a farm and have not set up my station yet but am currently on a LTE internet connection with a solar backup.
After reading your blog on the fires I think that may have been just the nudge I needed to get back into it.
VE7XML qsl KM6NHH(I messed up my cs in my earlier post!)
Ps just looked up your call sign, its interesting that in the US your licenses expire after 10 years, here in Canada its a lifetime license.
There really is not a decline in numbers, though. This seems more an attempt to make a single widget to replace needing hams. Communications in disasters is not so much a function of having the best power toys but rather the best operational doctrine.
Hams have the operational doctrine and also the flexibility in terms of tools to use. If the message doesn’t get through on one frequency band, change bands. If your transmitter modulation isn’t working, switch modes all the way downward to continuous wave Morse Code if you have to. The sun has been on a multi-week streak without sunspots so High Frequency communication will take operator skill to get messages through.
I think it’s more of a result of the recent availability of inexpensive low power (relatively) long range radios that operate on the ISM bands, i.e. LoRa.
APRS is probably the closest thing to this in ham radio, but it typically requires multi-watt VHF radios.
I wonder whether this project (if it's successful) would indicate that their numbers have declined past an inflection point, where their presence and availability is no longer assumed.