Your phone is a pocket-sized supercomputer, but when you don't even have cellular coverage to send a text message, it feels more like a paperweight. goTenna is a portable RF antenna that lets you communicate even when your phone has no service whatsoever. You won't be posting selfies to Instagram or catching up on your Hulu queue, but goTenna lets you exchange text messages and GPS coordinates with other goTenna users who are within range — and that range could be a mile or so in a city to a whopping 50 miles if you happen to be standing on top of a mountain.
goTenna is a flattish device a little under 6 inches long, 1 inch wide, and only half an inch thick. To turn it on, you extend the antenna another 2 inches, and an LED lights up to show you it's working. goTenna connects via Bluetooth LE to your iOS or Android device. So you use the app to tap out messages, which the goTenna device broadcasts over low-frequency RF, which is what gives it such great range. (It uses the 151154MHz end of the spectrum, where there isn't much crowding, either.) Since only other goTenna devices can receive the encrypted signal and send it to the app, goTenna is sold in pairs.
Shout it out
Using the app, you can send private messages to your contacts, or send a "shout" to every goTenna that's in range. Users can opt out of receiving apps from people they don't know, but if you send your blast as an emergency message, every goTenna that hears it will automatically pass it on the person's phone. goTenna's cofounder and CEO Daniela Perdomo got the idea for the product during the aftermath of Hurricane Sandy, when a quarter of all the cell towers were down, and neighbors came together to assist each other. So emergency mode sends out a call for help to everyone who can hear.
You'll get a delivery confirmation when your message goes through, and if it doesn't, goTenna will try again a few times and then tell you the message failed. You can tell it to keep trying, or move to another spot first, where goTenna's signal might be able to travel farther.
You can also use goTenna to let people know your location. Your phone's GPS actually works whether there's a cellular connection or not, but without a data connection, all you'll see in most mapping apps is a blue dot on an empty map. goTenna's app includes a free vector map of the entire world, and you can also download free map packs for the places you'll be traveling, to get more granular detail, down to the buildings on each street.
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