[hackerspaces] spread spectrum para-Internet?

Walter van Holst walter at revspace.nl
Thu Feb 16 11:46:48 CET 2012


On 2012-02-16 07:45, James Arlen wrote:

> While theoretically possible, one runs into issues around
> long-distance backhaul between nodes pretty quickly - land topology
> tends to get in the way and those pesky oceans are hard to cross.

It depends, Wireless Belgium has achieved amazing distances so far:

http://nodedb.wirelessantwerpen.be/?page=nodes

I think especially in rural areas it is a lot easier to get to 
alternative infrastructures using unlicensed spectrum than you may 
realise. ISP services tend to be outright poor in rural areas whereas 
the amount of buildings that get in the way of WiFi or free space optics 
is low. I think your average farmer is willing to look into allowing a 
WiFi repeater on top of a grain or fodder silo if that helps him and his 
neighbours to get proper internet.

OTOH, we've been looking into getting the Belgian network expanded into 
the Netherlands and the cost of each serious repeater node is pretty 
steep.

> Look at some of the mesh radio stuff and some of the early
> experiments in optical networking -- there was a DIY 10mb/s optical
> ethernet system at one point called RONJA that would haul over a
> pretty decent distance (approx 1 mile at 10mb/s full duplex)

The Ronja stuff is still around, the Twibright guys are amazing:

http://ronja.twibright.com/

One of the things that would be interesting to hack is finding out 
whether it is possible to use current generation high-power LEDs for 
this purpose. That might solve the current range limitations of the 
Ronja concept.

> As long as you steer clear of spectra that the government considers
> to belong to someone else, you should be fine -- and all of the old
> software is still out there.

The fun part is: especially free space optics is never going to be 
regulated at all.

Another avenue worth looking into for extreme long-distance 
low-bandwidth digital communication is meteor burst radio:

https://en.wikipedia.org/wiki/Meteor_burst_communications

HAM-licenses aren't too hard to get nowadays (they dropped the morse 
requirements) and given that this was feasible in the 60's, it should be 
doable at a much lower price now.

A big enabler for this would be open source modular phased array 
antennas for the 2 meter band. Anyone knows about a design in that area?

Regards,

  Walter




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