David Schneider Monitors Space Weather for Gamma Bursts, Solar Flares — Using Under $100 of Hardware

David Schneider has developed a means of detecting solar flares and gamma-ray bursts on a off-the-shelf laptop using no more than $100 in hardware — by connecting a coil antenna directly to a cheap USB sound card.

Inspired by the true story of the inadvertent recording of very-low frequency (VLF) radio signals from a nearby government radio station, intended for military submarines, onto the commercial release of Mike Oldfield's classic Tubular Bells, Schneider set about doing much the same thing — only deliberately, and targeting signal sources considerably further away.

"This inadvertent recording aptly demonstrates that VLF transmissions aren’t at all hard to pick up," Schneider explains. "And these signals can reveal more than just the presence of a powerful radio transmitter nearby. The application I had in mind was to use changes in VLF-signal strength to monitor space weather."

While most radio astronomy projects require expensive equipment, Schneider's entire setup cost well under $100 - excluding the laptop, required to run the signal detection software. "A coil antenna and external 'sound card,' which connects to a laptop computer," Schneider writes of his purchases. "Tuning the coil antenna to an appropriate frequency also required a signal generator, a protoboard, and an oscilloscope."

"The first few days of using this gear captured the expected pattern of daily variation in the signal from NAA, with sharp transitions when the sun rises and sets. Within a week, the sun became unusually active, producing three good-size flares in one day — as documented by NASA’s Geostationary Operational Environmental Satellites, which measure X-ray flux in geosynchronous orbit.

"Two of those flares occurred when the East Coast was in darkness," Schneider notes, "so they had no effect on the relevant portion of the ionosphere or the signal strength I was monitoring. But the third, which took place at about 11 a.m. local time, showed up nicely."

Schneider's full write-up is now available on IEEE Spectrum.