goTenna: off-grid messages & GPS tracking
If you are looking for an off-grid communications system for you or your family and you don't want to get your Ham Radio License (go ahead, its easy) then the goTenna might be just the solution you are looking for.
It's a small device which uses radio waves to send encrypted messages and location information, using your smart phone and a Bluetooth connection. You can send messages to one person or to groups. There is also a "shout" option where you can send an unencrypted message to anyone in range with a goTenna.
It runs off an internal lithium ion battery which can be recharged via Micro-USB cable. With a small USB battery pack one could imagine increasing the goTenna's 24 hour standby time to days or weeks. It's also ruggedized (although no IPX rating is listed) and stated to be water and dust resistant.
What does A goTenna do?
The goTenna unit connects to your smart phone using low-power Bluetooth. With the goTenna app (Android/iPhone) you can send encrypted individual or group messages, send GPS location information, or "shout" to anyone else around using a goTenna.
It uses VHF radio waves (2 watts on MURS) to send the messages between the units. What this essentially means is that you can use many of the key features of your cell phone without cell service.
There is no voice transmission however! Maybe in a future version...I asked the goTenna team about how they work on MURS, and which channel they use and this is what Molly from GT told me:
We use all of them! Our protocol actively executes listen-before-talk to avoid other MURS users on specific channels, and then opts to use the channel with the lowest noise figure so as to maximize field performance. All automatically!
That is pretty slick.
A couple of other points: the devices themselves store messages, so you could leave it hanging somewhere and come back to it with your phone to retrieve them. In the case of a send failure, the device will try 3x before forcing you to do a manual resend. This is to make sure you don't fry your battery - its a good call.
How Do You Use It?
As mentioned, the goTenna uses the US MURS Radio frequencies. Other countries regulate their band-plans in different ways so you might want to look into it before using one overseas.
Lets think of an emergency situation: powers down, cell service is either overwhelmed or non-existent and you, your family, friends and neighbors all need to evacuate. If you have the same FRS/GMRS or CB walkie talkies from Walmart that everyone else has you might not be able to find a clear channel to talk.
A better situation would arise if your family were licensed and you could hit the Ham frequencies with a dual-bander and good antenna setup like with a Baofeng UV-5R...but can you convince your teenage daughter to get her Tech license so she can use the radio?
Why not naturally use the device she is glued to 24-7 anyway...her cell phone? The goTenna should work perfectly in this case!
Maybe you are in a situation where voice communications would be detrimental, like a hunting trip or in a strange place where you don't want to attract attention to yourself and you are out of cell phone range.
With the silent messaging of the goTenna you can stay as quiet as you want to.
Let's not forget camping trips, although goTenna's app doesn't currently support topographic maps as I understand it so backcountry navigation should have a backup plan.
However the GPS should still work to at least give a general idea of another persons location, assuming you are within range of each other.
Speaking of range: the goTenna can have pretty great range although its likely in most ground-based situations you might only get a few hundred yards.
Four miles is possible under the right conditions. It completely depends on the topography you're in. You will also see reduced or no performance indoors or in a vehicle (so hang it out the window.)
What this device is designed to do it does very well. Its meant to be stupid-simple and utilize the same technologies we are already used to.
This has been one of the things about emergency communication thats bothered me for a long time: the high-level to entry (with licensing,) the cost, and complexity that keeps most people from putting together effective emergency coms. The goTenna makes it easy and inexpensive to get started.
Typical Price: $149
- goTenna helps you stay connected, when it matters the most
- Use your iOS or Android phone to send texts & share GPS locations when there's no cell coverage or wifi available
- goTenna creates its own off-grid network with other goTenna users in the area
- Send private 1-to-1 & group chats or broadcast to all users nearby
- Free goTenna app includes free, detailed offline maps for any region in the world
- Sold in pairs
*The original goTenna is no longer available, although you can find some on eBay. The goTenna Mesh has replaced it*
As a Ham I would like to see a few more features that may or may not be possible within the goTenna framework, but are certainly possible for those willing to put in the time and energy by utilizing different systems.
The first issue the goTenna has is its antenna, but this is the same problem any small radio has. I'll take a bad radio over a bad antenna any day since its the antenna that gets the signals out and in.
MURS does allow for the use of an external antenna, so perhaps one day they goTenna can implement the ability to attach one, although at this time they don't have that in the product development pipeline.
This would not only allow you to keep the unit itself out of inclement weather (and closer to Bluetooth range) it could potentially allow them to have an effective range of 10 miles or more by having an antenna up at 60 feet.
Replacing the existing antenna is unlikely - the unit is fused shut so opening it will destroy the housing (not to mention void the warranty.)
Also in that spirit the internal battery is not replaceable, but as Molly also pointed out most people wont be running them so hard as to deplete the cycle ratings of the batteries all that quick and fry them up like cell phones.
As with all lithium batteries its a good idea to charge them up a few times a year though so they don't drop to zero charge - they don't like that.
Terminal Node Controllers
For Hams, working with a Terminal Node Controller might be an option for you. Mobilinkd makes the TNC2, a small battery powered TNC (its a KISS TNC so it's technically a modem) that works on Android only and is good for portable work.
Jerry Clement, VE6AB has a great article about it that you can read here. Go check it out.
Jerry's sweet APRS setup[/caption]The gold-standard of TNC's is the Kantronics KPC-3+ which is a true TNC and digipeater.
It's a fairly small unit and pairs well with 2 meter radios, which gives you all the benefits of a base station radio. It has tons of features and is the most robust solution.
John Boiles has a great GitHub outlining the process and the parts needed. Very cool, super geeky.
I think this is a great product, and one that I really hope sees more development and additional functionality in future updates.
I'm filing it under my "why didn't I think of that" gear ideas. The price isn't prohibitive, you get 2 for $200, but not so cheap that I can see tons of folks running out and grabbing them "just in case" and that's a shame because the more people that do the better goTenna's would be.
I do think this device could be very useful in an emergency but my suggestion if you do get some goTennas is: test, test, and test them some more since your local topography and RF noise has everything to do with the performance you can expect from these.
I'm a little behind finding this out, but GoTenna recently announced their next generation of communication devices, the GoTenna MESH. This new model will add the functionality of having the devices communicate with each other by relaying messages in a network, similar to the way computers do. They are selling them for $149 with pre-order right now. We'll do a deeper review once we get out hands on them to test.
Our goTenna Guide & Review is up! Go check it out.