Using goTenna's Pocket Antenna to Send Texts Without Cell Service

Inspired by the downed cell towers and utility outages of Hurricane Sandy, the folks at goTenna wanted a way to keep smartphones connected even when the grid fails. What they came up with is a pocket-sized handheld antenna that lets users send texts and location info without cell service. And we got to see a prototype in action.

goTenna is a battery-operated 2-watt radio and antenna that connects to Android or iOS devices via Bluetooth LE. When activated by extending the device's antenna, the goTenna establishes a radio connection with any other goTenna devices within broadcast distance. Once connected, users can send texts up to 160 characters or share their GPS coordinates.

Using goTenna's Pocket Antenna to Send Texts Without Cell Service

At goTenna's office in Brooklyn, NY, Daniela Perdomo let me use the system by sending text messages between an iPhone and an iPod Touch, each connected to a prototype goTenna device and put in Airplane mode to cut off cellular connectivity. Texts were sent and received instantaneously through the companion goTenna app, which shows nearby goTenna devices in a contact list.

The app lets you text an individual, a group, or every nearby goTenna device. You can choose whether or not to be visible to any other goTenna device within earshot for public communication, though you can't opt out of the built-in Emergency channel, where users can text all nearby devices if they need immediate help.

Using goTenna's Pocket Antenna to Send Texts Without Cell Service

In ideal conditions, Daniela says, the device can broadcast up to 50 miles, though she was quick to point out that in real-world testing in Central Park, the range was more like 3.5 miles, and in the densest parts of the city it dropped to between half a mile and a mile.

The app uses proprietary vector maps (since neither Apple nor Google's map apps will update without a cellular or Wi-Fi connection) and your device's built-in GPS radio to pinpoint your location. You can send a map pin of your location or a point of interest to a friend and it will show up on their map, though for now there's no provision for step-by-step navigation. Vector maps are available by region for the entire globe, Daniela told me, and users will be able to download map packs for regions of interest—when they're on the grid, obviously.

The antenna's battery should last for up to three days of normal communicating (a few texts an hour), or 30 hours of continual heavy usage. Since the system uses decentralized, asynchronous communication, messages aren't stored on any sort of hub or server, though they are encrypted end-to-end.

goTenna may have been dreamed up in response to a natural disaster, but that's not the only use case: Daniela explained how users could avoid choked networks at concerts and other public events; keep in touch and share location data during off-the-grid camping trips; or send private, encrypted texts without exposing the contents to a public network.

Of course, that highlights the gadget's biggest drawback: it's a closed system that only lets you communicate with other goTenna users. That's fine if the people you're camping, partying, or post-apocalypse surviving with are also goTenna equipped and within range. But grid-disabling disasters are, by nature, unpredictable, and while the folks at goTenna certainly hope that everyone you know will buy one of their ruler-size devices before the next hurricane season, early adopters will probably have to loan out their second doodad to anyone they want to chat with off-the-grid.

If that's an acceptable tradeoff for you, goTenna is taking preorders now, with shipments promised in late fall. Preorder pricing is $150 for two devices, going up to $300 a pair once the first units have shipped. Map updates and messaging, Daniela tells me, will always be free for users.