Comment on What if the Internet Goes Down? - 15 Jan, 7PM CET
cmnybo@discuss.tchncs.de 2 weeks agoKeep in mind that without working repeaters, the baofeng will only have a range of a few miles on level ground with nothing in the way. If the power goes out, most of the repeaters will go down too. Some have battery backups that may last a few hours to a few days. Depending on where you are, a few may be solar powered, but heavy use will drain the batteries. Some repeaters are also reliant on the internet for linking to increase the coverage area.
What you really want in that case is a portable HF radio and a wire antenna you can string up over a tree branch or a support with a fishing pole. In the daytime, you can use the upper HF bands for long distance communication. That has a range of thousands of miles, but nearby stations won’t be able to hear you if they are beyond line of sight. Since the portable radio doesn’t have much power, you may need to use digital modes to get through. For more local contacts you can use NVIS propagation on the lower HF bands. That has a range of several hundred miles and can even be used to talk to someone on the other side of a mountain. Even 5 watts and an antenna strung 3 feet off the ground can work for voice contacts out to over a hundred miles.
I’d be interested in reading a debate thread on Lemmy about this.
What the pros and cons to different communication methods are following a disaster that neutralizes mainstream methods of communication.
Benn Jordan just did a video on Meshtastic and other decentralized tech, so I’m inclined to believe in mesh technology. But I’m also curious about the high frequency stuff you mention
The four repeaters in my area are run by one club. They do the Field Day exercise every year and from what I remember they run them around 150w per repeater. A small jenny could run those fuckers on 15gal a day fairly easily. In a huge emergency, though, you can relay morse on just 5w through 5 or less relaying techs to most of the world without repeaters at all. (1 if you’re lucky, but I’m being fair to real life interference).
Yeah… if I am trying to reach people tens of miles away during The Apocalypse, I am already dead.
Anyone who is within range to be helpful (or… not) would generally be within signal range of a handheld.
What about after surviving the initial disaster? During the rebuilding?
Long-distance radios are useful as hell in stuff like The Last of Us.
That’s not an emergency scenario, that’s an apocalyptic scenario.
True, you make a good point.
I did know I was referring to an apocalyptic scenario rather than an emergency one. The giveaway was that I was replying to this comment:
Yeah… if I am trying to reach people tens of miles away during The Apocalypse, I am already dead.
🙂
If you are in a situation where you need help, the odds of someone (even the person you have been talking to for weeks on the radio) doing a day or two journey to MAYBE be able to reach you is pretty slim. And such long distance communication has other implications for bad actors.
And in the event of “rebuilding” some kind of community, you aren’t going to be using a handheld device at all. You’ll raid… I don’t even know what at this point (I miss Radio Shack) to install a radio on the tallest building you can find. Oh, a HAM Radio Nerd’s house. That’ll work.
Whereas if you are trying to communicat4e with others and signal for rescue? Whatever you can get from walking up a hill/mountain or climbing the stairs to said tall building with your handheld is probably about what you can expect.
Same with in stuff like hurricanes and the like. If you are in a region that is at all hospitable then the relief teams know to send helicopters/people to that area. And if you are in the kind of situation where even a few hours might mean the difference between life and death… odds are nobody is coming.
HF handhelds do exist. Do they have the range of a dedicated HF rig? No. Better than a Baofeng? Yes, and they’re about $10 more.
Like what? Can you name one?
Radtel RT-880 comes to mind. Baofeng-level handheld capable of HF comms. I got one for ~$50.
drosophila@lemmy.blahaj.zone 2 weeks ago
I don’t know much about radio stuff, but ever since I learned about LoRA I’ve wondered what kind of range a station could get if the longwave or AM bands were repurposed for use with a spread spectrum digital protocol. And what kind of bandwidth something like that would have.
I think being able to do datacasting over really long ranges would be useful, so, for example, you could send emergency alerts to people even if the local cell infrastructure was down. But with the way things are headed I guess that role will be taken up by satellites.
cmnybo@discuss.tchncs.de 2 weeks ago
For LF and MF, you typically want narrow signals, not spread spectrum. It’s hard to make wide band antennas for such low frequencies and propagation can change a lot in just a few tens of kHz.
drosophila@lemmy.blahaj.zone 2 weeks ago
I see
In your opinion is there anything useful we can do with that part of the radio spectrum as those stations switch off, or are those frequencies going to be silent in the future? Will they be turned over to hobbyists maybe? (or would the power requirements be too high at those frequencies?)
cmnybo@discuss.tchncs.de 2 weeks ago
The AM broadcast stations aren’t going anywhere, at least in the US. Above the broadcast band is mostly aircraft, marine and the 160 meter ham band. None of that is likely to change.
Below the AM broadcast band are non directional beacons. Those are slowly being decommissioned. Eventually they will all be gone and that spectrum may get repurposed. I don’t know what the spectrum may get used for, but it would be nice if the 630 meter ham band was expanded.
LF and MF can be used at low power. The 2200 meter ham band has a power limit of 1 watt EIRP and the 630 meter band has a limit of 1 or 5 watts EIRP depending on the country. Actually radiating that much power is difficult because it’s not practical to build an efficient antenna. Luckily there is no limit on how much power the amplifier can put out, so we can put hundreds of watts into a very inefficient antenna. Narrow band digital modes work great on those bands.
In the US, we have LowFER, which allows hobbyists to use 160-190 kHz for experimental use without a license. The power limit is 1 watt input and the transmitting antenna is limited to 15 meters. People still manage to make long distance contacts with those significant limitations.