Signalling dissent
Found on The Economist on Friday, 18 March 2011
With a tin can, some copper wire and a few dollars' worth of nuts, bolts and other hardware, a do-it-yourselfer can build a makeshift directional antenna. A mobile phone, souped-up with such an antenna, can talk to a network tower that is dozens of kilometres beyond its normal range (about 5km, or 3 miles).
Some activists brought laptops to places like Tahrir Square in Cairo to collect, via short-range wireless links, demonstrators' video recordings and other electronic messages. These activists then broadcast the material to the outside world using range-extending antennae.
Directional antennae, unlike the omnidirectional sort, transmit on a narrow beam. This makes it hard for eavesdroppers to notice a signal is there.
Censorship will never work. Sure, the government can try and block quite a bit of information, but the interesting parts still make it through.