When there is no network, a smartphone isn’t so smart. Jorge Perdomo understood that notion when he came up with the idea for the goTenna. Using the unlicensed, 151-154 MHz, MURS (Multi Use Radio Service) band, Perdomo and his colleagues developed a device that uses Bluetooth low energy to pair with a smartphone; essentially turning the smartphone into a sort of walkie-talkie for providing text and other digital information, such as GPS coordinates, to another smartphone or group of smartphones.
Using these relative low frequencies and a 2 Watt radio, with the right conditions, the goTenna can reach distances of up to 4 miles in rural areas and 1 mile in urban areas with line-of-sight at elevation. As pointed out on the goTenna website, adding obstructions and being at ground-level reduces coverage. Still, even a limited coverage can mean the difference between life and death when in a remote area or under a pile of rubble. Perdomo explains that the text and GPS capability is the ideal communications for the goTenna, as voice provides limited value when trying to describe location.
Perdomo’s idea for the goTenna was spawned at a concert where he was trying to find his friends and he did not have a good cellular connection. Today, people are using the goTenna to stay connected in off-grid situations. Perhaps the most interesting application is as a back-up radio for emergency situations, such as when the wireless network fails because of a catastrophe.
The cognitive radio that is the basis for goTenna seems like it could be adapted for more sophisticated communications in emergency situations. Perdomo indicates that they have had a great deal of interest from first responders and others who have a need for robust and secure communications.
He points out that future features, like mesh capability, is largely dependent upon FCC rules regarding spectrum. What goTenna has developed is reminiscent of the work of Krishnamoorthy and Srikrishna and their idea to create a social mesh network that could also be used by first responders. With the FirstNet RFP now released, it will be interesting to see if any entity proposes a device-first approach to create a robust emergency communications network.
[Update – 09/30/16 – goTenna announced a mesh product that operates in the UHF band. Although it has a slightly lower point-to-point range of 1 to 3 miles, its power is in its ability to create an ad-hoc network of goTennas. This means that an intermediate(s) goTenna would repeat signals, effectively increasing the range. The signals are encrypted, so only the intended receivers can see the content of the messages. There is also a group mode, allowing one-to-many communication. Available in the U.S. in December 2016, goTenna’s Kickstarter campaign for this product is live at https://www.kickstarter.com/projects/gotenna/gotenna-mesh-off-grid-people-powered-connectivity.]