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.
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.
... or a carrier pidgeon with an SD card, it would seem :-)
All these numbers are from google summaries, without further source checking.
Couriers are more reliable, though still not perfect.
African or European?
Human speech has an average rate of 39bps.
https://www.sciencemag.org/news/2019/09/human-speech-may-hav...
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.
If you're talking about compression, Q-codes[1] were invented long before most of us were born.
Any increase in effective data rate of speech afforded by Q codes can also be used to increase the data rate of data transmission.
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.
https://github.com/mozilla/LPCNet https://github.com/drowe67/codec2
Conceivably one could reach 39 bps with near-realtime speech, tone, inflection and tempo recognition. Put the result into a zstd compressed SSML stream and perhaps even reach 16 bps. https://stackoverflow.com/questions/46108940/is-there-a-way-...
Does anyone know such a cryptographic system?
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.
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...
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.
BTW my recent emergency experience is documented here:
http://www.friendlyskies.net/fmk/index.php?tpl=PSPS-Ham-Radi...
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.
Yeah, but we don't have to re-test, and it can all be renewed online for free.
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.
In related news, see https://www.rrmediagroup.com/News/NewsDetails/NewsID/18899
APRS is probably the closest thing to this in ham radio, but it typically requires multi-watt VHF radios.