Fediverse over line-of-sight optical links.

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Or radio for places that get a lot of precipitation.

Line of sight is much harder to DoS. It's still possible, but the use of a high-gain directional antenna limits where any jammer would need to be. And encryption means that at best they can induce packet loss.

I need a killer app for a project like this. Doesn't matter if most of the links are tunneled through the Internet at first. The problem is getting people interested. The Internet is "good enough" for most purposes, but it's been getting worse and worse over time, while search engines, filters, and various kinds of regulation cause ever greater distortions and chilling effects.

@freakazoid Entirely doable. You can do federated datacomm with UDP over dialup style!serial.

You can also do it over QRcode: A big television that shows QRcodes at or just under maximum size (3072 bytes) and a webcam on the other side. Which means that you can also run NFS with jumbo frames over it.

This is something that we experimented with at Project Byzantium.

@drwho What kind of data rate were you able to get with that, and over what distance? Theoretical maximum if you show one QR code per frame at 60fps (probably too fast for reliable capture) would be 1,474,560 bps if I did the math right (3072 * 60 * 8).

@freakazoid Not much. We didn't do any serious testing, just calculations. Our intended data rate for our use case was 2400 bps, 9600 at most, unknown experimental maximum.

Building a diode laser transmitter turned out to be really hard. Never got it working reliably.

Just remembered, our layer-2 protocol was intended to be ax.25.

@freakazoid In the early 2000's a university in Europe somewhere built 10mbit optical links by connecting infrared LEDs and Photodetectors to AUI ports on older ethernet cards. It was reliable enough that they connected various buildings on campus that way.

Sadly I'm not able to find it anymore; the name I remember pulls up a bunch of Fortnight influencer garbage now.

@aaron I remember a ham I knew doing similar with 10GHz Gunnplexers. They had an analog input that controlled the frequency, so ultimately it was just frequency shift-keying.

@aaron Now that I think of it, there was also someone at a Field Day I attended sending voice using an optical transceiver they'd made using a fresnel lens. I don't remember what the light source was, but I think it was just a really bright red LED. They were modulating and demodulating using a 2 meter mobile radio transceiver, presumably because an FM signal is a lot more robust to any kind of interference.


1. Point two high zoom cameras at each other’s lens.
2. Add a screen to the wall of the rooms of each camera, such that the reflection is calculable and detailed.
3. You now have effectively created a transmission system.


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