I remember reading about this in the late 90s, open hardware was a fairly new concept then. But you needed to be an electrical engineer to make one yourself, more or less; I wanted to build a pair with a friend so we could play gamed (this was in dialup times). Soon broadband made it obsolete for casual users in urban areas.

There's a modern day equivalent, with up to 10Gbps capability using infrared - http://koruza.net/

Yes, the difference is in speed and distance (150m).

And size.

I saw these in use a few years back by some alt-net hackers, but I haven't heard hide nor hair from RONJA since then. Which is a pity because it really seems to me that this is a technology that could put the 'net back in the hands of the people - with a handful of these inexpensive devices couldn't we build a "Peoples Net" revolution?

Off to find out if someone is commercialising this yet by offering DIY kits, etc. ...

I built one of these years ago, didn't use that that much though. Totally supersed by radio these days.

One interesting use of free space optics is working around legal issues. At least in Australia the Telco act (via reference to the Radiocommunications Act) only goes up to 420THz which is red colour, so free space optics can be unregulated.

I remember those being used back in the late 90s - when point-to-point radio links were prohibitively expensive and/or too noisy. Is this still worthwhile, other than as a quirky historical device?

> The device has 1.4km range and has stable 10Mbps full duplex data rate.

I'll go out on a limb and say 'a quirky historical device'.

If the devices could do 10Mbps in the '90s, a similar effort could do much better now.

The range is tricky, especially in fog, but mountain to mountain links (single channel audio) have gone 173 miles.

Nah. I've been looking into this, actually: you're up against all sorts of physics constraints, unless you want to go laser (beam dispersal, air humidity, lens size...), and with lasers, it gets legally tricky. There are technical reasons this hasn't caught on, the 10 Mbps is indeed the theoretical upper limit (people used to lovingly call them "fog density meters").

You haven't been looking very hard, this is a commercial 10Gbps system that does 7 kilometers in clear skies: http://artolink.com/page/why/

I was mainly referring to the hobby builds being able to do better.

In clear skies. Around here, that's a big if - with the other side of the disclaimer reading "...and if the weather is not perfect, you get no link at all." Perhaps useful in other regions, though.

Not true, they offer 10Gbps on 2.5km distance, 7km distance is for 100Mbps with radio backup only.

Since you have way more knowledge in this area than I do, would it ever make sense to use a radio frequency laser (if that's even possible) for point to point communication? Like, to cut down on signal loss and etc. in much the same way as visible light lasers perform better than LEDs. I'm completely unknowledgable about physics, so that may not have made any sense XD but I'm interested in the answer!

It would work better - but I'm pretty sure that the decisive factor was cost: back when this was conceived, getting a useful laser would have driven the cost 10x higher. Plus, I think there's some pesky law on coherent light output power and whatnot (and another which bans lasers outright if you're close enough to an airport).

Aah, makes sense that they wouldn't want to foul up any instruments that rely on RF/microwave. Thanks for the answer :D