QRSS: Radio amateurs’ slow-speed narrowband


Host of the Soldersmoke podcast, [Bill Meara], contributed this guest post.

While the rest of the world is moving toward high speed broadband, some hams—including one Nobel Prize winner—are going in exactly the opposite direction. Our ‘QRSS’ mode makes use of an unusual mixture of modern digital signal processing (DSP), ancient Morse code, and simple homebrewed transmitters. Very narrow bandwidth is desirable because this reduces the noise in the radio communication channel, greatly improving the S/N ratio.  But Shannon’s communication theory tells us that narrow bandwidth comes with a cost: slow data rates. In QRSS, beacon transmitters using only milliwatts churn out slow speed Morse ID signals on 10.140 MHz that are routinely picked up by DSP-based receivers on the other side of the globe. Many of the receivers, ‘grabbers’, have visual outputs that are available online in real time. QRSS has been getting a lot of attention on the Soldersmoke podcast and on the Soldersmoke Blog. For more information check out this overview and the hardware involved. Here’s a gallery of received signals.

Blinkenlights’ Stereoscope goes live in Toronto

We’re happy to present this guest post from History Hacker’s [Bre Pettis]. Today [Bre] catches up with the Blinkenlights team, who turn entire buildings into displays. Their current project is Stereoscope which goes live in Toronto, Canada today.

Earlier this week, I posted about the beginnings of the blinkenlights project. It started in 2001 in Berlin, but now Seven years later, in May 2008, blinkenlights is back. The City of Toronto asked the blinkenlights team if they would be interested in joining another Nuit Blanche (as they did in Paris in 2002). Short on time and with a lot of ambition, they decided to redesign and push the envelope on the project to make it wireless for The Toronto City Hall since there would be 960 windows split up in two towers. In the above photo, you can see Stereoscope in all its glory. [Read more...]