kelabar
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Post by kelabar on Aug 27, 2020 17:10:49 GMT 10
I saw a comment elsewhere recently about using smartphones as local transmitters and receivers. I think it was special software that changed the function of the phone. An alternative for walkie-talkies is the best way to describe it from what I understood.
Anyone heard anything about this? I think it is experimental and not very reliable at this stage but this is something that has promise IMO.
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blueshoes
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Post by blueshoes on Aug 27, 2020 19:17:38 GMT 10
That's a really interesting concept, i would love to know more about it
There are text chat apps that work peer to peer but i haven't heard of anything that does voice peer to peer yet. I suppose it should be doable over WiFi
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kelabar
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Post by kelabar on Aug 28, 2020 20:22:41 GMT 10
Thanks, @blueshoes. Do you have more info or a link on the text systems? I did a search but all it came up with was mass texting by political parties. I think what I saw didn't involve a phone service, it enabled the caller to call another phone directly, so doesn't use phone towers. I would imagine it would line-of-sight only or pretty close to that but I can still see potential in it.
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blueshoes
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Post by blueshoes on Aug 28, 2020 22:51:47 GMT 10
I'll try and look up more later but as far as completely serverless, Briar App does text chat over internet, wifi or bluetooth - we tested it and found that it works well for adding friends directly over bluetooth and has a mesh network structure.
You both have to add each other for the connection to work, random strangers can't add you nor can you send friend requests to anyone (you add someone but they see nothing unless they add you also).
Downsides as it stands: because it's hyper encrypted, you have to enter your password; you can't delete messages; it drains your battery listening for and relaying messages in the background (might be a necessary evil in bad times).
It doesn't have a good function that lets you give someone the app over bluetooth - that would help if the official app store is down...
It's very basic but it's a beginning. It seems to be designed more for privacy/safety than functionality
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kelabar
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Post by kelabar on Aug 29, 2020 1:10:31 GMT 10
Thanks, that's awesome. I understand some of it! But it will probably get banned. For info: briarproject.org/One big advantage is the ability to keep any EM transmissions local so detection is difficult from long distance. Nice.
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shinester
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Post by shinester on Aug 29, 2020 6:07:30 GMT 10
Keep local... true, trouble is the solution is also a problem, aka short ranged. Depends what you're looking for. Talkie - haven't tried it, looks like wifi voice chat. Might be useful for neighbors. play.google.com/store/apps/details?id=com.remaller.android.wifitalkie_lite&hl=en------------------------------------- - anyone who truly knows comms please correct as required, I'm not a professional. If we were playing rabbit and fox, you're the rabbit and I'm the fox and I'm trying to find you. I would need equipment, a CB with a scanner, and preferably a second with a directional antenna. [most people don't have one, though a very skilled radio guy might be able to build one if need be out of a coat hanger or tin foil]. [I'm not that guy] I need to be looking for you and find your frequency. I could use a scanner which is like pushing the 'search' on a car radio, you can scan channels till you find an active one. You're only active when you transmit [talk]. So if you don't talk, I'll never know you're there. If you talk infrequently I might then set up a radio to stay on your channel. This 'search' will be in a limited band of radio, typically you would have to have an idea of what frequencies to look for as there's a lot of frequencies and time I'm 'searching' is time I'm not tuning into a channel. Now lets say I found your frequency and you never changed it and you talked at a time I could predict or you talked all the time [clue] I could listen in and 'when' you transmitted [not any other time] and I could use a directional antenna to find an approximate compass direction. It takes a little time to sweep it around and find the strongest single direction, though not too tricky. If you transmitted only a few times a day, I'd probably have to wait all day to be sure. I would then also have to find 'another' compass direction after traveling some distance to draw two lines on a map, assuming you don't move. [clue] Same deal here as the first one. So with both compass directions, I could draw two lines on a map and get an approximate location of the transmission. From there I could travel to that place, assuming it doesn't move. [clue] So I need to find the frequency, find the compass directions two times from two different places to zero in on where a transmission is coming from. It's possible. I just spent 2-3 days trying to find someone instead of something else in an Austere environment and I would have to be fairly close [5kms or less] to your location and be looking for people [scanner] and manning that radio to notice transmissions. I haven't the man power for that, I can barely manage the very basics of security. What benefit is it to me, lets say I see you a few kms away and you're on comms and I'm listening. I would gather intel, try to figure out all I could and then for what? If I were a bad guy looking for resources, why take on the organized guy with radios with multiple people? Now lets say I go looking for wifi, it's essentially the same technique but less range, if I get up high I can see further and find more, though it might tell me who has power. Useful I suppose if I were the bad guy. Wifi transmits 'hey I'm here' all the time, so it's much easier to find. An old technique is using a pringles can as a directional antenna. Essentially screw off the antenna top from a USB and screw it into the pringles can with a few other piece of metal [could be tin foil]. Now I can go hunting Your phone will tell you when there's a wifi nearby. Easy to see someone nearby has wifi, it's transmitting all the time, for a phone, it's a couple of houses, for a pringle can antenna [or similar] then it depends on terrain, though up to a 1km if you're up in a tree for instance. Depends what you're looking for.
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blueshoes
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Post by blueshoes on Aug 29, 2020 9:20:26 GMT 10
Oooh Talkie looks promising, I'll have to have a play with it! (Also Google Play suggested Slide2Talk which seems to need a server to make connections though) Interesting trivia: you just described finding someone who is transmitting over radio. In South Australia's Senate a few years back, sen. Rex Patrick mentioned in his "maiden speech" (1st speech to parliament) playing Fox Hunt which is precisely that... australianpolitics.com/2017/12/04/sen-rex-patrick-nxt-sa-maiden-speech.htmlYes transmissions make you vulnerable to detection in a way which just listening to broadcasts doesn't. And you make a good point about WiFi, anyone driving past (or "war driving" which has nothing to do with war) can see your network unless you *turn off ssid broadcast* which means it's only visible when in use. If SSID broadcast is turned off, you have to tell your phone the SSID to connect to it. As a side note, i don't know about Apple but i know most Android phones store wifi network and passwords, and this is synced to Google's servers. It can be turned on/off, but given Google's propensity to collect data while permissions are off... they must have the name, hardware address (and in many cases a password to connect) of a majority of wifi access points in Australia. At one point even the street view trucks were collecting wifi ssid's! The location of each wifi point is known, and if you're using an android for navigation, turning wifi on allows google to use signal strength of nearby wifi hotspots to triangulate your exact location.
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kelabar
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Post by kelabar on Aug 29, 2020 12:43:52 GMT 10
Found this. I suspect all of them use existing phone networks but Intercom is Bluetooth based so I think it would only need two phones. www.makeuseof.com/tag/best-walkie-talkie-app/Is it possible to use a 'hotspot' WI-Fi router as a repeater? (I have very little idea what I am talking about so the jargon may be completely wrong.) To increase the range of phone-based transmissions? Or are there Bluetooth repeaters? I would imagine it would be frowned upon now but if things go pear-shaped no one will care about allocated frequencies, etc.
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shinester
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Post by shinester on Aug 29, 2020 13:00:58 GMT 10
Hmm, you can get wifi extenders, which at a guess work like repeaters, better still if you put them up a tree with a better antenna and a solar panel/batteries. I'm liking your thinking and the advantage of wifi is everyone has a phone, could connect a neighborhood with a few of them and a solar panel to charge. extender eg - www.netgear.com.au/home/products/networking/wifi-range-extenders/default.aspxLooking at it, seems like you can get up to 100m outside. There's probably other options such as creating a mesh network, aka joining a bunch of differing devices together. Yeah for sure you can hide your identification SSID, you might be on a winner even if the range isn't great, having a couple of streets worth of people connected in an emergency could be valuable.
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kelabar
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Post by kelabar on Aug 30, 2020 10:43:37 GMT 10
I'm liking your thinking and the advantage of wifi is everyone has a phone, could connect a neighborhood with a few of them and a solar panel to charge. Yep, I was ignorant of this possibility. I had assumed that phones could only communicate with the towers so were useless without them. I made the same mistake with LPG, handy but storage is a problem, until someone pointed out that LPG vehicles will run on BBQ gas. Bingo! But if phones can 'talk' to each other then the options open up. Walkie-talkies are good but there won't be enough of them. All you young 'uns have at least a dozen smartphones (maybe not quite that many!) so any way of using them together means there is a heap of comms hardware out there already. Also if phone comms can be set up this is easier and requires no training for normal radio comms. "Talk, over", "reply, over", "more talk, over" works but is a PITA. And the big selling point "If you do this your phone will ALWAYS have power and never go flat" A fate worse than death for millenials!
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kelabar
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Post by kelabar on Aug 30, 2020 11:01:28 GMT 10
A Bluetooth system is limited by range. Probably not suited to a town or neighbourhood but could work on a farm where there are up to 7 families/households. The 7 device limit is a system limit AFAIK. Blue tooth uses very little power but the phones would need to be powered all the time, not sure how much additional power is used if Bluetooth is active. Voice comms may be possible, I think a Wi-Fi system would be better for this, not sure at this stage. At minimum it could be used as a bulletin board. It could be set up near a longer range comms system, UHF, 27meg, Ham and used to relay incoming messages and weather reports as text. Or set up at a central location and used to transfer lists, notices, any sort of general info to everyone. Ideally both messages and phone comms could be setup on the same system. Push-to-talk systems as used in walkie-talkies would be OK, most apps use this at this stage I think, but 'talking on the phone' type comms are easier and quicker.
Still looking into Wi-Fi systems.
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blueshoes
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Post by blueshoes on Aug 30, 2020 15:35:00 GMT 10
While you're looking into wi-fi systems, a key piece of info nobody's brought up yet might be this: Mesh Network standard 802.11s en.wikipedia.org/wiki/IEEE_802.11s802.11a, 802.11b etc are the standards wifi networks use to communicate, 802.11s is related to this but i don't know where it's at with implementation.
It was developed in conjuction with the OLPC project, which aimed to create indestructible, basic laptops for distribution to third world countries. OLPC laptops, last i heard, had hand-crank charging, a icon based (no words) interface to be language agnostic, and a peer to peer mesh network protocol (as reliable internet access isn't always available in the third world). A 'mesh' network is a decentralised - serverless - network. Not needing a central server is important, as central servers are both a point of weakness and likely to be unavailable if you are using P2P anyway.
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kelabar
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Post by kelabar on Aug 30, 2020 16:34:19 GMT 10
Great link, thanks. These are called SPANs, Smart Phone Adhoc Networks, a subset of Wireless Ad Hoc Networks. From the wiki 'Wireless Ah Hoc Network' page: "Most recently, Apple's iPhone with version 8.4 iOS and higher have been enabled with multi-peer ad hoc mesh networking capability, in iPhones, allowing millions of smart phones to create ad hoc networks without relying on cellular communications." No idea if that is a recent version or not. Bluetooth does support up to 3 voice channels: www.elprocus.com/how-does-bluetooth-work/, so could be used for phone comms but not for everyone at the same time in a 7 device system. Would work for 3 or 4 devices though depending on how it works. The wiki page on Bluetooth also has good info. Transfer rates of up to 721 KBps. On a larger scale could possibly use a local server to support the whole system. A Linux distro , OpenWRT, supports wireless mesh networking so no cost. Set a laptop up with one 'tower' (high antenna) and use it to receive and transmit calls around the phones. Dunno, that is getting bigger. I have no idea about most of this so it could make no sense. I will just keep adding info I think is relevant as I find it. There is more than likely already software out there to do all this but the telcos are going to get a bit annoyed if everyone starts calling each other without them. So it may be discouraged or hidden.
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blueshoes
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Post by blueshoes on Aug 30, 2020 17:35:40 GMT 10
There is more than likely already software out there to do all this but the telcos are going to get a bit annoyed if everyone starts calling each other without them. So it may be discouraged or hidden. Actually, there's a more pragmatic reason than that - your device being part of a mesh or SPAN network involves your device constantly listening to and relaying messages in the background which have nothing to do with you. If you think of what it's like when your phone/computer is downloading updates while you're trying to work, you get why that's annoying - and it flattens the battery much much faster also (and if the towers are down, your phone will be using more battery trying to find a phone tower, too).
This is a necessary evil if there's really nothing better, but it is a good reason why everyone doesn't just adopt it right now
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kelabar
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Post by kelabar on Aug 30, 2020 21:59:34 GMT 10
Ah, yes, I am at the edge of phone reception a lot, the phone goes flat in 6 hours or so constantly searching for a signal. So a different operating system may have to be used on the phones unless the standard mobile service can be deactivated without turning the phone off. Maybe use a boot option screen to select which OS to run. The ability to switch between each easily would be a better option allowing use now rather than waiting until the towers are dead. Either way, with the towers dead or running, some way of stopping the searching for towers may be needed if the software is still running on the original OS, is this what airplane mode or whatever it is called does? Or the dedicated server idea might work if not. Totally different software running a custom phone service that doesn't actively search for signals. Then power use can be concentrated at the server and it would 'ping' the phones to wake them up. Or something. Hell, I don't know! It may just be easier to run cable for small networks and use normal landline phones and cordless phones and their bases! No EM signal then. And there are still a few normal phones around. Some members may be wondering why this is of such interest to me. I am old enough to recall a time when I didn't know what the voices of my overseas relatives sounded like. I recognised their handwriting from the few letters and the Xmas card they sent during the year but that was it. Overseas phone calls were possible but very unreliable. The world is a lot smaller now and if comms go down it will be much less stressful if you can somehow get word of how your loved ones are. Also it is easier to get things done with better comms and give quicker warnings. But primarily to reduce stress and reduce the need for travel to get information. One thing I will mention is war. During war, communications are actively targeted. If your system transmits there is a good chance that a missile with a 100kg high explosive warhead will destroy the area where the antenna is within minutes. Or artillery fire within seconds. Or enemy troops may turn up within a few hours to search the area. Plan to have multiple systems/lots of antennas if you want to keep communicating, and don't be physically near the antenna while transmitting.
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shinester
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Post by shinester on Aug 30, 2020 22:49:42 GMT 10
I've looked into this and seeing a lot of things I had seen previously, not a lot more range. Wifi - you can indeed build a mini mesh network, great for a house, not much more. - you can add on an amplifier taking the typical 200mW of power up to 8W with an add on between the router and the antenna [simple to do], though at best 4W might be legal [and I'm not certain of that!]. Range of a typical router to 4W seems to be 40% increased. Remember range IS diameter, so that's a lot more houses nearby. - Directional antennas for wifi [replace omni-directional] can have quite significant ranges into the kms, potentially 25kms. Not much use outside the 'beam'. Lots of hints from people who know much more than me forums.whirlpool.net.au/archive/2554426An example of the 4W amplifier You can get 1km extenders made for outdoors, the price made me laugh, $700USD. That's a lot of baofengs for less range. Remember the transmitter of the 'phone' also matters it has to reach the wifi-extender. Mesh - there are mesh kits though they're more for home use - the main problem you need a LOT of mesh units [each costing more money.. radios = cheaper/easier] - android phones 'can' do it but you have jailbreak/source them from what I can see. - the software side of things still seem immature.
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kelabar
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Post by kelabar on Aug 31, 2020 2:38:43 GMT 10
Thanks, shine. Excellent info. Way past where I had got to.
With an amplified router the system could cover a neighbourhood or small town. Reception on the outskirts may be lower but the phone could be set in a good spot and used with the loudspeaker feature to communicate. I have never thought that the system could actually be used with the phones when mobile but with more signal strength this may be possible. Another router on top of a silo, water tower or TV antenna tower (even a windmill if that is the tallest thing around) could use an omnidirectional EDIT: MEANT DIRECTIONAL antenna to send the main router signals to a 'repeater' router over 10k away. Line of sight is critical here but routers acting as repeaters could chain to send signals to another town many 10s of kilometers away. A compatible system in that town would allow phone comms between the towns (maybe). Hopefully at minimum a 'push-to-talk' (PTT) system using currently available apps should be possible. Nice. If not, text. Farm owners would likely be happy to look after the repeaters in return for a working phone system.
Yeah, actual radios would be much better. But there are tens of thousands (millions?) of smartphones out there and people can use them without training. Maybe thousands of routers too. A system could be designed and the hardware and software needed kept until needed. Then it would be a matter of "Oi, you. Plug your phone into this cable and download the software." Bingo, they have a working phone they already know how to use. And USB charging is everywhere now. Very easy to charge phones.
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shinester
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Post by shinester on Sept 3, 2020 11:22:16 GMT 10
The problem is you can only receive [tower is 4W] and not transmit [router is 0.1W], unless you made/had directional antenna for all of the routers [now acting as access points]. Max range at 0.1W is about 1.5km outside. Directional antenna [out a window is fine] would be better. Many routers have multiple channels [hence multiple antenna] and you could use one of those antenna as your directional antenna to another access point with the amplifier as well as keeping omnidirectional antenna for the immediate area. Longer ranges due to the 4W probable. Line of sight is critical here but routers acting as repeaters could chain to send signals to another town many 10s of kilometers away. A compatible system in that town would allow phone comms between the towns (maybe). Hopefully at minimum a 'push-to-talk' (PTT) system using currently available apps should be possible. Nice. If not, text.Yeah, voice over IP should work fine, not sure on the applicable apps, but internet is essentially a large network like we're creating. My thinking is a single network, though the more people on it, the more repeaters/access points the less bandwidth. Still are ha ha. But there are tens of thousands (millions?) of smartphones out there and people can use them without training. Maybe thousands of routers too. A system could be designed and the hardware and software needed kept until needed. Agreed. It's worth looking as a possibility. Then it would be a matter of "Oi, you. Plug your phone into this cable and download the software." Bingo, they have a working phone they already know how to use. And USB charging is everywhere now. Very easy to charge phones. Charge phones, yes, though power from? [solar,.. who has batteries, yes car batteries and who has 12V charging?] Phones aren't much use unless near a router as they only have 15mW of wifi power. Didn't know this till now, it's the real limiting factor in the wifi networks not the router. So, maybe you set up routers talking to one another and acting like access points to the water tower with directional antennas. This hub can be chained to the next place if you can get line of sight. Each needing probably 2 amplifiers, 1 to transmit omnidirectionally and 1 to transmit to the other town. Hooking up routers and powering them with a car battery max drain 70% should keep them going for a bit. You could charge them from household solar panels if you had someone who knew how to convert to 12V. . So you would get a lowered bandwidth network [1Gbit total] and you could probably use phones with an app if you were near anyone's house.
You would have to know how to make this work before any event so you had all of your apps, connections and devices squared away as well as a bunch of manuals for routers you're not familiar with [what IP address they have and what is the typical admin password].
I would only be confident if I could put together a working example 1. get a couple of routers and network them together
2. make one on battery power [portable]
3. check for what range I can get out of it, router 100mw to router 100mw. - try PTT on phones for utility. [CB radios are still looking better] 4. from there invest in amplifiers and see what range I can get omnidiretionally and directional. 5. place up high and see what kind of practical range I'll get within a community. 6. check an access point near the practical range limit and try with phones.
7. get pdf manuals for many common routers 8. put all into a kit with charging options [so you're independent of having to source that] so if you need the network up, you just plug it in and zip tie it to whatever you're putting it on.
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kelabar
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Post by kelabar on Sept 3, 2020 18:41:43 GMT 10
EDITED MY LAST POST I meant a router with a directional antenna could send signals to repeater routers. Better range. Duh. Good info. The phone can only transmit at 15mW. But could still receive from an amplified router (up to 4 or 8W). So messages could be transmitted over a wide area but phone comms only over a much smaller area. I didn't realise routers had multiple antennas. (I just searched for images of them! I don't know tech stuff .) That simplifies things. One router on top of a silo could directionally send to multiple other repeater routers and cover the local area too. Less hardware and power needed. If a router was placed on one side of a silo it could cover between-town comms as well as the local omni network. But one side of the silo would be 'dark'. Is it possible to use an antenna extension of some sort to position a router antenna on the other side of the top of the silo to avoid blind spots? How do the large scale wi-fi systems work, like in office buildings or libraries. Do they use more powerful routers, more small routers or have a separate system? Anyone know? Anything with more transmission power would give longer between-towns range. Charging and running the hardware won't be a real problem IMO. Nearly every new solar panel and battery pack has at least one USB port. USB adaptors for 12V cig lighter sockets are available. Even computers have 'always on' USB sockets these days. Or fire up a computer and use the 10 or 12 USB sockets they have. And as you mention the zillions of solar panels on roofs and in solar farms. Converters are commonly available and I believe MPPT controllers can handle voltages up to 65V or more, depending on design, and output 12V. (Must check common solar panel voltages). At worst "Hey, young person. Yes, you. The one going catatonic because your phone doesn't work. Jump on this magical bicycle which is connected to an alternator and pedal for 10 minutes. Abracadabra, your phone will work again.?" They will be lined up out the door! Not really concerned with the capability of the system. Just that one could be created. Even if only text could be broadcast to all phones in an area this would really help with defence. Two-way text would be excellent for medical emergencies. Any comms between towns would rock. Pony Express and stagecoaches are nice but 'push-button' is easier. You would have to know how to make this work before any event so you had all of your apps, connections and devices squared away as well as a bunch of manuals for routers you're not familiar with [what IP address they have and what is the typical admin password]. This is the bit that confuses me. The SSID stuff @blueshoes was talking about above, access, compatibility of different hardware. www.lifewire.com/accessing-your-router-at-home-818205Can routers have a new OS installed over the old one? So system software that already has the 'ad hoc' ability could just be overwritten onto all routers? It would seen easier although a brute-force way of doing it. Or do all wifi routers use the same system? So compatible with all others? And great checklist. I've saved that.
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Post by illuminati on Sept 4, 2020 16:22:55 GMT 10
Yes you can install new OS on routers but it depends on the router. Some you need update from vendor, others are supported by open source projects like OpenWRT etc.
WiFi has limited range but directional antennae can make a p2p link further. You might setup a bridge between two properties.
Using apps that will upload and download messages when they have connectivity, such as simple email could be handy or a bulletin board (forum), wiki people can edit etc.
Regarding mobiles, you could setup a base station (BTS), a femtocell, basically your own network but without a license it’s illegal. You can get femtocell repeaters from Telstra etc that extend their network, they control it so it’s ok legally.
HAM can send digital packets, probably pretty far, further than WiFi but IIUC it has to be in cleartext so everyone can spy on it. IIUC it’s illegal to use encryption or any scrambling, obfuscation, etc.
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