I lead the technical efforts at one of the charities in Ukraine; we're now trying to rebuild connectivity for people in some of the areas where much of the civilian infrastructure was destroyed and Starlink® is not a viable option, or perhaps "not-to-be easily scaled option."
The world of long-range Wi-Fi is a wild one!
We are now trying to evaluate the cost of a point-to-point mesh network using commodity hardware, and so far have only experimented with Raspberry hardware to work the antenna, and some Atheros AR9331-based SoC's. The idea is to make a single device that can act as both a relay station, as well as an actual hotspot, it then can be placed in line-of-sight configuration to potentially cover huge areas (the accepted performance would be anywhere from 0.1-1 Mbit/s point-to-point over anywhere from 5-20km. We are aiming to bring the cost of such configuration down to $100 per unit at least. Hopefully, we also wouldn't need to do so and somebody else could do the whole thing for us at a similar price... Where would you start, i.e. with the vendors, as well as the commodity hardware, firmware that should work best for a setup like this? Bonus points; if it can be somewhat be aware of the current happenstance. In terms of bleed from Electronic warfare deployed by the enemy in Ukraine; it has to work hopefully in adversarial environment!
Best regards, Ilya The Stone Cross Foundation
Most of them are using commodity hardware from Mikrotik, Teltonika and Ubiquiti. Basic setup for a personal node is just an antenna + router. Then they usually have the concept of "supernodes" who are responsible for hooking up multiple personal nodes, and have uni-directional antennas + multiple ones + bigger routers to facilitate the routing.
I'm not sure you'll be able to put together a supernode with decent range for under $100 though, think the cost would be more than that, but I would be happy to be proven wrong.
In terms of firmware, I've almost exclusively seen OpenWRT being used (and the rest running default Mikrotik/Ubiquiti firmware), with various self-made patches done to it before installing it on the hardware.
Use the router's switch ports to connect them with each other, and use one local router with stock antennas pointing straight up to serve local clients and mesh with possible nearby mesh nodes.
The electronic warfare resilience is going to involve hacking the collision avoidance techniques to be sufficiently less aggressive, and likely to get Freifunk to use encryption for the mesh links. If necessary, just set up P2P links with per-link encryption. Routing-table-affecting nodes in a mesh sadly need some inherent trust to be performant in the non-adversarial case, or at least, no one seems to have tackled that possible issue yet (to the point where you could just compile existing software for the router at hand and get something working by the end of next week).
(I have no affiliation with UBNT, I just use their stuff at home)
Honestly, as you are in Europe, you should look into the European Hamnet. See https://hamnet.eu/site/community.html and https://www.tapr.org/pdf/DCC2014-TheEuropeanHAMNET-DG8NGN.pd.... They aren't using WiFi, but the goal is the same.
Both of these require licensed amateur radio operators to use normally. (Maybe wartime is a different matter). I do believe I heard that Russia took radio transceivers away from operators in the Ukraine, but don't know much about it.
Also, keep an eye on different editions, as I believe last one is a little less tech focused and more into how to run a community project, both sets of knowledge are highly important but second edition might be outdated in regards to software availability in OpenWRT and Linux in general.
The only thing that matters for 2.4/5 GHz wifi long range is height above surrounding terrain to get line of sight. The highest technology is literally the technology to get the antennas highest; ie poles, towers, tops of tall buildings, actively lifted (and powered) drone platforms for antennas, sides of mountains, etc.
For long distances, you will probably need to "scavenge" bigger dishes (1m diameter) from other sources to be within budget. IIRC, any microwave dish will be useable, including satellite tv dishes, if you use a suitable transceiver-antenna "head" (DIY-able) and align it. In addition, tv dishes on buildings look inconspicuous.
Ideally, the wifi radio should be placed in the focal point of the dish and directed such that the reflected signal points to the horizon. But most TV dishes are not symmetric to allow them to be mounted vertically (and avoid collecting snow) while pointing into the sky.
You might need to read up and figure all this out.
1.) Raspberry PI Zero antenna mod: https://www.youtube.com/watch?v=IZqaKZLIqFg
2.) Cheap DIY Antennas: https://www.youtube.com/watch?v=TPt-sw3kvw0
Be sure to check out this guys whole youtube channel (@andrewmcneil), he is awesome and its about DIY antennas (from cheap to expensive with real in depth tests)
3.) There also is a ready to use but expensive product from Ubiquity called "Air Fiber" for high performance connections over long range. See LTT for more details: https://www.youtube.com/watch?v=e9P_R-ApD-g
Some general hints:
- Reliability and a stable connection are probably even more important than just range, so reliabale hardware and a stable drivers are mandatory
- That's why I would not order too many devices at once but just check out, how they work (especially TPLink is known to have problems here, although their devices are best for the buck)
- If you could purchase devices, I would probably take a look at the recommended devices section on OpenWRT (https://openwrt.org/toh/recommended_routers) or try to buy bigger batches of used devices for real cheap money
- In the near future I would probably check out the GL.iNet GL-MT1300, which is cheap and small or maybe TPLink Archer A10, both with mediatek chips
Slot antennas are something flat and high-gain which might be easiest to deploy, once you get constructing them figured out.
I also built my own 3G range extender with an almost identical off-the-shelf $50 Yagi antenna at a country cottage (2.2 and 2.4GHz are close enough for an antenna to carry both), so I've spent a while pondering those kinds of scenarios.
But addressing your points directly, I would look for OpenWRT-compatible devices with external antenna ports and the ability to do both 2.4 and 5GHz - and most likely try to use 2.4 for long-distance point-to-point links with Yagi antennas.
Hitting the bitrates you mention seems perfectly doable, although I must point out that the antennas are conspicuous (about the length of two Pringles cans). The challenge I found is having router hardware that can pin SSIDs to separate radios, because most of the modern stuff aims for diversity and prioritizes throughput.
I don’t recall bitrates. The area was well over 500 km^2
project is here: telescopearray.org
Even if you don't buy from them it can give you an idea of what exists, some price ranges and availability. Some outdoor devices (small router + integrated antena + pole mount + weather proof) can be cheaper than a raspberry pi alone, example the TPLink CPE605 cost ~40€ without taxes.
Look for hardware that is supported by OpenWRT, so that all community firmware should work.
Ubiquity UAP AC LR also has long-range access points with up to 183 meters range for ~$109 USD: https://store.ui.com/products/unifi-ac-lr
If you are more ambitious, you can deploy an OpenWRT BATMAN-based mesh network: https://openwrt.org/docs/guide-user/network/wifi/mesh/batman
I recommend using something that supports OpenWRT out of the box, such as GL-iNet Mango Mini Router GL-MT300N-V2 (~$20 USD refurbished) https://openwrt.org/toh/gl.inet/gl-mt300n_v2 https://store.gl-inet.com/products/certified-refurbished-pro...
Please only use this information for humanitarian/civilian purposes and not for military objectives. Thank you!
Sounds like WiFi HaLow could be an option here
https://www.cnx-software.com/2021/12/21/wifi-halow-gateway-k...
The Internet Society have some resources on community networks here: https://www.internetsociety.org/action-plan/2022/community-n...
And then there's the Things Network, which operates over the LoRaWAN (Long Range Wide Area Network) protocol: https://www.thethingsnetwork.org/
Lastly (and potentially not super relevant), there was a talk at LibrePlanet 2021 about efforts to set up community networks in Turkey (although more from the perspective of ensuring user freedom): https://media.libreplanet.org/u/libreplanet/m/freeing-networ...
I think 20km point to point is not to be sniffed at if my back of a napkin calculations are correct (would love someone more knowledgeable to correct!)
Firstly on LOS - that’s like 15m+ masts at each end of the link (assuming perfect LOS path with no clutter like trees or buildings).
Then on free space path loss you’d be looking to overcome around 100db+ of path loss i think assuming 2.4ghz ISM band and perfect atmospheric conditions.
10dbi / 12 dbd log periodics for 2.4ghz are available off the shelf and are very reasonable to use (not too big, not too much wind loading at 15m elevation, weatherproof etc.)
Recieve sensitivity should be around -110dbm maybe? Assuming fairly rural conditions so that you’re not also dealing with a man made noise floor (and also benefitting from a very directional antenna to miss most noise too).
You’d need a 1 watt power amplifier minimum, again that’s more or less off the shelf but there’s restrictions globally on use and that may make sourcing harder.
A NanoVNA - (less than $200 on Amazon/Ebay) This little tool will help you understand how transmission lines work, along with antennas, matching, etc. You can use them to test antenna matching, and gain, etc. If you want to roll your own high-gain antennas, etc.. this is an amazing piece of kit to have at a low price.
Not as directly applicable, but effectively free. GNU Radio -- This will give you a feel for signal processing, and how RF stuff works internally... it works with audio I/O so you can experiment for effectively $0. If you get to the point where you understand I/Q signals and "negative" frequencies, a lot of things become clearer.
Existing point-to-point solutions would be even better but I am sure you (some other comments also point to this direction).
I also want to add that at low datarates like 0.1Mbps, you probably can't just bridge it to the internet and expect it to work well. You'll want to be careful about who and what access is allowed. 0.1Mbps is plenty for relaying messages point-to-point for multiple users, but even one user searching google or using slack will saturate it. A few users trying to load gmail will probably not work at all.
Lots of great ideas in there - even if you decide to not use their gear. They pioneered repurposing Intels otherwise failed wimax for long range links in lue of microwave. The other nice thing about Ubiquiti is you get really nice management platforms for "free" - included with the cost of the equipment. There is much to be said for being able to see all your radios and links within a nice, convenient dashboard.
BTW I'm in Kiev, first time hear about The Stone Cross Foundation. Could You tell more about it?
I'd rather have a way to do long range data directly between two phones.
A cantenna is cheap and can easily bridge around 2-5km if there's not much noise on the spectrum.
If you want to create a meshnet, you should look for OpenWRT compatible hardware in terms of routers and clients.
There's lots of ralink or RTL based USB wifi dongles that also have support for gnuradio so you could also switch frequency bandwidths if they got a tuner on them.
An easy and stealthy low-bandwidth meshnet can easily be created with old DVB-T usb sticks because the RTLSDR allows flexible channel hopping and key rotations, if necessary.
There's also lots of RTLSDR projects that use the LoRa spectrums, and they might work if you are looking for a text based communications network. That's why I mentioned it. There's also the OsmocomBB project which also has support for RTLSDR in case you want to create your own DIY GSM network with IMSI catchers and the like :)
Wi-Fi usually has the problem that the 2.4Ghz and 5Ghz frequencies are overloaded with noise, so they are hard to tweak into a long range mesh network.
For short range coverage you may want to consider repurposing commercial hardware (routers, access points etc) that supports OpenWRT, those should be easier to find, also used, and way cheaper than specialized hardware. https://openwrt.org/toh/start
Long range communications will require directional antennas, which implies mostly fixed and point to point. Also to achieve line of sight and avoid the fresnel zone obstruction the antennas need to be mounted higher than the highest obstacle in between. Solar power is viable, but battery backup should also be provided. Antenna masts and solar panels would make them visible from distance, and of course although the traffic can be encrypted, they scream all around the air that there is a station operating there; hidden SSID does not make their operation invisible to a spectrum analyzer or any specialized electronic warfare gear - of which the enemy has plenty - that should be taken into consideration.
Anyway, Mikrotik makes some interesting powerful wireless routers like the Metal 52 ac which can operate at over 1W both on 2.4GHz and 5GHz. They're conveniently bullet-shaped and can be supplied by PoE, so that you can connect them just behind the antenna (either directional or omni) to achieve minimum losses. I've bought some good WiFi hardware, cables and antennas at netek.eu (now wifimarket.eu) and batna24.com. Mikrotik is Latvian, Batna and Wifimarket are in Poland, you shouldn't have problems shopping from them. Wifimarket today seems to have a very reduced product line compared to a few years ago when I shopped there. They had really good antennas and cheap really good quality parts to build antennas (dipoles to make patch antennas by adding a reflector etc.) that would come very handy on the field. You may ask them if they still sell them elsewhere. (btw. no affiliation here, just a happy customer)
Think about using fiber optics at least for longer fixed paths: a couple routers with SFP can provide a gigabit connection over several kilometers, and the fiber cable can be easily buried so that it's not easy to notice and doesn't hint the enemy that a transmitter is operating nearby like WiFi would certainly do.
For very slow and long distance communication, namely text messages, LoRa can be an option to which encryption can be added externally. All other considerations about radio transmission remain valid for LoRa too, however. You may find these links interesting:
https://disaster.radio/ https://meshtastic.org/
Also worth of mentioning for different purposes: https://github.com/ExpressLRS/ExpressLRS
Best luck with everything. слава україні!