In the 1890s, Tesla experimented with the concept as a possible alternative to Marconi’s wireless telegraph. But the device’s relatively short range and high signal noise made it impractical for widespread use.

Now a team focused on a concept developed over a century ago by Nikola Tesla, had shown that a magnetic wave generator could be used for wireless communications.

Basically, the generator works like an electromagnet. Powered by standard alternating current or battery, it runs electricity through a wire that is coiled around a metal cylinder, creating a harmless, low-energy magnetic field that extends for hundreds of meters.

Just like radio, the field can carry an audio signal by modulating (raising or lowering) its strength instant by instant. But unlike radio, cell phones, and satellite phones—whose electromagnetic waves can’t pass very far through rock, clay, or other materials that conduct electricity—a magnetically generated signal penetrates the ground easily.

On the other end, a coiled antenna wire about 100 meters long receives the signal, and an amplifier converts it into sound.

The team solved the problem of signal noise with the same type of digital signal-processing software used in cellular phones, LeVan says. The software also allows users to send and receive text messages.

Each generating unit can operate at least 24 hours on 12-volt battery power, which complies with U.S. It poses no danger of sparking, which could set off an explosion if methane gas is present.

Read more at ScienceMag.org