Communicate Off-Grid Digitally via Amateur Radio
As you probably know you can use radio waves to talk to people over the air. But did you know you could also send digital signals as well?
Using a laptop /tablet/smartphone in conjunction with a Terminal Node Controller (or not) and a Radio you can send messages and files via radio waves.
Using Packet you can send messages which can be routed between TNC's.
With other digital modes you can send files, emails, and photos.
This article is a brief overview about a few possible ways you could get a system like this setup.
Packet Radio Overview
First we will start with Packet Radio. Its been around a long time and allows users to send messages or have real time keyboard to keyboard chats.
Packet Radio can make use of Terminal Node Controllers, which can forward messages to other TNC's, greatly increasing their operable range.
They can also store messages for later retrieval, like a digital bulletin board.
A TNC contains a modem, a computer processor (CPU), and the associated circuitry required to convert communications between your computer (RS-232) and the packet radio protocol and software you are using.
A TNC assembles a packet from data received from the computer, computes an error check (CRC) for the packet, modulates it into audio frequencies, and puts out appropriate signals to transmit the packet over the connected radio.
It also reverses the process, translating the audio that the connected radio receives into a byte stream that is then sent to the computer.
TNC's can be separate devices, or can be built directly into a radio.
Read this article for more detailed info on how the software and hardware generally works: Introduction to Packet Radio
Terminal Node Controllers
Typical Price: $230
A commonly used TNC controller is the Kantronics KPC-3+. It can connect to your computer via USB and to the radio with a serial cable. It offers:
- "Keyboard to keyboard" communications
- Personal Mail Box
- Local area node
- Remote control devices
- Remote access of telemetry
- Network node operation
- BBS operations and message forwarding
- GPS position transmitting and tracking (requires external GPS receiver with NMEA-0183 data output)
- Data storage and retrieval
- EMWIN Weather Information (additional software required)
The Best Laptops for ECOMM
There are two schools of thought here when it comes to laptops being used in the field for emergency communications.
- Ruggedized and Weather Resistant is better or,
- Smaller and Lighter is better.
The choice is up to you and your budget. Lets look at both options so you can decide for yourself.
But here's the catch...if you are into Emergency Communications, or want to be able to quickly put together networks for organizational purposes then there is definitely something to be said for having a PC at your disposal.
Several prominent manufacturers make laptops which are built to be used in harsh conditions: rain, snow, freezing cold, dust, etc. The most notable are Dell, Panasonic, Getac, Lenovo, and General Dynamics.
They are usually completely overbuilt, have swappable bays, some offer dual batteries, and some have serial ports which can connect directly to a TNC without a USB adapter.
These laptops get very expensive quickly, but if you look around on eBay you can usually find used ones in the $300 range.
Suggestion: if you do buy a laptop on eBay, learn how to reformat the computer and reinstall an operating system on it, you never know what you're gonna get with a second-hand computer, but its totally worth the cost savings to go this way.
Here's a list of some older models you could look for on eBay to save $$:
- Lenovo ThinkPad X131e: Inexpensive. Some ruggedization added to casing.
- Dell Latitude XFR: More external reinforcement. Touchscreen.
- Panasonic Toughbook: Drop-proof. Stylus. 3G built-in.
- Getac B300: The best. Certified to MIL-STD 810G, IP65 and MIL-STD-461F standards. Endless list of features. Or if you want to go crazy look at the X500...wow.
There are a lot of reasons why a smaller laptop makes a better bug out laptop: weight and size being the two most obvious. Also having a spare along isn't going to be too difficult. They aren't as durable of course but there are ways to handle that.
The most important thing to look for is battery life and performance - don't just shop on cost alone or you may wind up with a sluggish machine that lasts an hour unplugged.
The undisputed winner here is the Apple Macbook Air. We have both 13" and 11" sizes and they are amazingly powerful.
The hardware is very reliable and the performance can't be beat. Plus they are so diminutive as to almost disappear in a pack.
You can find a 2011 13" for about $350 on eBay at the time of writing. On these older models its still simple to change the battery and the SSD Hard Drive (not the RAM or processor.)
If you go this way, make sure you check the cycle count on the battery - they are only rated to go to 1000 cycles or so and its $100 replacement (there are cheaper batteries but I don't trust them.)
They are way more power then you will ever use and they will be relevant for another 10 years or more. I also have an Asus X205 11" Windows Laptop that I got from Best Buy for $200 on Black Friday.
I put Windows 10 on it and it runs like a champ and I'm quite impressed with the speed, battery and screen. The only problem with it is its odd proprietary power connector, but a computer like this will serve you well.
Which OS is Best?
This ultimately comes down to preference. There is probably more software available for Windows then Macs but that's not to say Macs are left in the cold. They aren't.
There are also lots of options for Linux users as well. The nice thing about the Apple laptops is the fact they can run all 3 OS's simultaneously.
And what about tablets?
Dell Latitude 12 Tablet starts at $1,849 - but it's meant to be bulletproof. Amazon sells refurbished ones for about half price. If you buy anything with the links we provide on this page we get a small percentage of the sale from Amazons end. For more info click here.
Tablets are great for consuming information, but aren't the best for inputting information. Still, they can be an viable option for your Bug Out Bag, and several folks have compiled great lists for making one - like Creek Stewart's guide.
If communications are your thing, the tablet can help to some degree. Take a look at this comprehensive list of software available for tablets relating to Ham radio. Pretty great, but you can't use a TNC or program radios with them...yet?
There are of course other reasons a laptop can be helpful. You can have all your important documents on it, you can entertain yourself and the family with games and movies, etc.
Having a tablet or kindle is another option. Or carry your important documents on a USB key or Hard Drive...although without a computer they don't do much good.