On a winter's night in 1894, a 20-year-old Italian inventor named Guglielmo Marconi invited his mother into his attic workshop. Leading her to a table, he pressed a switch connected to an elaborate apparatus that produced a spark and a snapping sound. Instantly a bell sounded across the room. Marconi had linked the switch to the distant bell, but by sending a wireless signal through the air. The technology was primitive by modern standards but also strangely precocious. More than a century after the first "spark gap" transmitters crackled into life, wireless technology is returning to its roots. The latest ultrawideband wireless devices, which are just starting to appear on the market, have much in common with the very first transmitters. History is repeating itself.

The signals from those early transmitters built by Marconi and his contemporaries sprawled across the electromagnetic spectrum, unlike those from modern radio transmitters, which broadcast on particular frequencies. Today's cutting-edge ultrawideband radios are now going back to transmitting over a wide range of frequencies simultaneously. They use very low power levels to avoid interference with traditional radio broadcasts: ultrawideband transmissions are invisible to conventional radios, and vice versa.