[Florin_Andrei]

KG6YHQ here. It's doable, but if the wired net becomes unusable and you have to rely wholly on the RF spectrum, bandwidth would be stupendously tiny. Forget about sending anything else but, basically, text-based messages.

Perhaps in an event like that a decision would be made to temporarily open up the spectrum, but even then there are only so many of us, only so many transceivers out there.

I feel the HAM net would be more useful after a natural catastrophe, where the infrastructure would be destroyed physically. Which is exactly what a lot of us are preparing for.

[eternalban]

"Perhaps in an event like that a decision would be made to temporarily open up the spectrum"

Or, depending on who shut it down, you may have to deal with jamming.

[harshreality]

Wouldn't SDRs be a lot more useful for creating higher-bandwidth wireless networks in the sort of disaster where the FCC opens up other frequency ranges?

The amateur radio regulation regime and common ham radios work well for small numbers of small messages sent around in a well-regulated way, without the government initiating a frequency band jubilee. But beyond that, HAM radios are limited, even if they're modded, and the cheap SDRs are even cheaper than baofeng handhelds, so where does that leave amateur radio in a real frequency free-for-all? I think what would matter is, as mentioned above, availability of SDRs, and secondly, parties of people tracking down transmitters that are messing up the ad-hoc sdr wireless nets.

[Florin_Andrei]

Sure, but everything has to be ready, prepared and exercised before anything happens. Whatever plan you may conceive, you have to do plenty of test runs in advance. After it happens, it's chaos, it's too late to start new initiatives.

And there are caveats anyway.

For local connections, some kind of WiFi mesh might still be the best option.

For long distance, I don't think you can currently use anything but proper HAM equipment, and fairly large power at that. For a reliable connection, especially at good bandwidth, you need lots of power and a good antenna. But if you blow standards out of the water, and start pumping out huge bandwidths at huge powers, you run again into a tragedy of commons - you're taking up large chunks of spectrum over entire continents.

There is no free lunch.

[acidburnNSA]

As a fellow ham, I have to say: guys, guys... it's ham, not HAM. Other than that I totally agree with you.

The (VHF and UHF) ham bands will send data a few tens of kilometers with good messaging bandwidth. Here in Seattle there's a Monday-night digital net through a repeater on the Columbia tower where folks send text messages and some (slow) photos on 444.55 MHz. Typical speeds are like 9600 baud.

As you mention, when you go down to the HF bands like 20m you can transmit and receive around the world, but there's far less bandwidth. The tragedy of the commons is right on.

I've operated PSK31 (which runs at 31 baud) worldwide on 20m and it's pretty much a chatroom. You can get a lot said with that, but you certainly won't be browsing the web.

It would be cool to play around with connecting 2.4 GHz local wifi meshnets with ham repeaters at ranges of say 50 km. Then you'd have nice fast local communication with reasonable long distance. .

[nbadg]

There's also the issue of the dubious legality of using encryption over eg HAMNET. Modern internet without encryption simply isn't modern internet.

[elihu]

The legality of encryption on ham isn't dubious, it's explicitly not allowed.

I don't know if there's any legal precedent or official policy regarding digital signatures; I would guess that they're probably okay because they don't obscure the meaning of the communication and anyone can verify them against the sender's public key (assuming that the public keys are published somewhere).

Communication with no privacy but with cryptographically secure signatures might be acceptable for emergency situations. It's unfortunate that ham rules are sufficiently restrictive that most of the tools we use on a day-to-day basis wouldn't be legal to use without substantial modification. But then again, we wouldn't want people trying to log into Facebook/Youtube/Reddit etc.. when the network runs at like 1200 baud (if it's packet radio on the 2 meter or 70 cm bands) or maybe in the low mbps (if it's over some kind of 802.11 b/g/whatever mesh network operating under part 97 rules).

Fortunately, while part 15 rules are pretty restrictive about power, they're less strict about antenna gain, so it's at least theoretically possible to make multi-mile connections without having to operate under ham rules. Building a large network out of point-to-point links with directional antennas, though, would be pretty difficult and laborious even in a non-disaster situation, so realistically I think the best local disaster communications option at the moment is to just use APRS and analog voice over 2 meters and accept that 1980's technology that sort of works is better than a modern internet experience that requires a lot of infrastructure that isn't working or available.

[nbadg]

My understanding is that it's a little bit more grey than that. Modification of signals with an intent to obscure the content of the transmission is explicitly forbidden. But obfuscation for other reasons is not expressly forbidden. So there's a question of "is this incidentally encrypted, or intentionally encrypted", which is (again, from my understanding, which is very limited) why I'm calling it dubious and not simply "forbidden".

[celticninja]

Could the spectrum be opened up "unoficially"? i.e. Is there a "switch"the govt would need to throw or is it more that you cannot use the spectrum for fear of prosecution, so with no govt you could just decide to use the available spectrum?

[gaius]

Forget about sending anything else but, basically, text-based messages.

What's the downside?

[mhurron]

No one wants to go back to the age of ascii porn.