The goTenna Off-Grid Communication Device: Take A "Cell Network" on your next Field Trip

Imagine co-leading a science field trip indoors in a large museum with questionable cell coverage, or outside and too far from the nearest cell tower. The goTenna system allows you to directly contact another goTenna equipped teacher using their smartphone independent of a cellular connection. The goTennas are their own communication network that runs between the phones. And there is no limit to the number of goTennas that can play together.

The goTenna solve a couple unique problems that make them indispensable if you need such solutions. By basically creating their own network between devices, the goTennas allow popular smartphones and Android and iOS tablets to gain text messaging capabilities and possibly map-based GIS locations over a range up to a mile.

The tablet or phone uses Low-Energy Bluetooth to talk to the goTenna through an App interface so the goTenna device and phone must no farther than 10m of each other. Then the goTenna’s take over and the distance between any two goTennas can traverse much greater distances depending on the amount of terrestrial interference (buildings, trees, mountains, etc.). The goTenna uses radio waves in the 151-154 megahertz range.

The operation of the goTenna is straightforward and intuitive. The actual goTenna device is a little larger than a Sharpie pen, and turns on when the antenna is deployed by pulling it straight up out of the top of the goTenna case. A white LED light indicates activity. To turn off the goTenna, simply re-stow the antenna by pushing it back into its case.

Charging the goTenna is just like a cell phone using a microUSB. However the connector shroud on some microUSB cords might be too short to fully engage the contacts in the goTenna. The pair of included microUSB cords has extended connectors so they should not mingle with the rest of your microUSB cords in case you grab a cord that doesn’t easily fit. I have modified some cords on the fly using a razor blade to shave down the size of the USB plug. The charging port on the goTenna is at the opposite end of the device from the antenna, and secure under a rubberized cap. The goTenna is weatherproof and seems fairly durable given the number to times I’ve dropped mine.

The goTennas are designed to be attached to a backpack or bag and away from the human body since proximity or touch to a person degrades the goTenna’s signal reducing its range. A strap with a snap makes for easy and versatile attaching to other objects, but the snap seems a little primitive compared to more modern buckles and fasteners. I also don’t quite trust a snap to keep my $100 (each) goTenna unit forever attached to a backpack daypack or shoulder bag while traversing the very country where a goTenna is needed.

For each user’s smartphone, the goTenna is two parts; a powered antenna system and an App. The free App is downloaded from Apple’s App Store and on Google’s Play Store so it should work on any recent iOS and Android device regardless if phone or not. This means you can load the app onto a basic tablet and essentially give it cellphone-like text messaging.

Before You Go

The App shows the battery life of the goTenna, but only if the App is installed. I’ve encountered a few times where I wanted to use the goTennas on the fly, but the reason for the goTenna is when there is no cell or wireless service, so you certainly cannot download the App at that time. Further, any maps that need downloading (which is all of them) must be done while in traditional connectivity like within a wireless network. 

There are three options for messaging between any two goTennas; a 1:1 directly to a specific goTenna, a group chat to all goTennas within range, and an emergency setting that identifies the message as a priority. A variation of the messaging is a request for the other user’s GPS location which the app can share if the phone or tablet is GPS enabled and the goTenna app has access to that data.

But wait. There’s more!

Taking this a step further, the goTenna antenna device also contains some onboard memory to remember messages it receives when the host device is out of range of the goTenna, switched off or has a dead battery. When a charge to the tablet or phone is available again, the saved messages are loaded as soon as the phone connects to the goTenna.

An exciting update to the goTenna family is the upcoming release of a mesh-network compatible version named the goTenna MESH. This new option allows each individual goTenna MESH device to create a bridge a between other goTenna devices. So you could imagine each goTenna MESH being at the center of a transmission circle perhaps with a two mile or more in diameter. Any overlap between goTenna MESH circles provide a continuous wireless network as long as there is a connective pathway between all signal circles.

While cell networks are fairly common, around the country, there are still plenty of places with spotty coverage, or no coverage. Walkie-talkies are a great solution for general speech contact, but they have limitations and require realtime attention. Leveraging the wonderful asychronious capabilities of text messaging, and GPS location sharing makes exploring new directions in so-called “off grid communication” something all teachers should be aware of when leaving the classroom with their students.

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