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?

When communications are down, but you need to communicate long distances there are a few ways to do it. Voice communications are the defacto standard, but sometimes the "bands" are too noisy to really be heard over the "noise" of the band (think "static".)

 That's where digital modes over radio come into play. 

We're going to write this article in a way that assumes you don't know much about how radio works but if you are a long term Ham, hopefully you'll get something out of it too, we'll try to make this relevant to you as well. 

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What is a Radio Digital Mode? 

So what does a "digital mode" mean? It's effectively like using online chat but over radio rather than the internet. Those of us old timers will remember using the telephone and a modem to connect to the internet, remember all the funny noises it would make when starting up? Thats kinda the idea, except in this case we aren't using AOL Chat, but a program like VaraAC or JS8Call with an HF (High Frequency) capable radio and antenna not a Pentium based Windows 95 with a landline.

You can also use a laptop /tablet/smartphone in conjunction with a piece of equipment called a Terminal Node Controller (TNC) with your radio and you can send messages and files via radio waves as well. Using Packet (small digital signals, its a type of digital protocol) you can send messages which can be routed between TNC's.

With other digital modes you can send files, emails, and photos even without a TNC, as long as the radio you are using has a built-in sound card. Most base stations these days do, but small hand-held radios typically do not. 

We're going to look at using TNC's to transmit digitally, and using built-in sound cards to transmit using software only. 

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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. You can also use a radio with a sound card, more on that later. 

Some TNC's 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

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Terminal Node Controllers

Here are two of our favorite TNC's. We don't have any affiliation with either company, but have used thier products personally and can attest to their usefulness. 

Kantronics KPC-3 Plus

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. This is a great option for a home radio setup - i.e. your "base station" 

It offers:

• "Keyboard to keyboard" communications
• Digipeater
• 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)

$230Kantronics

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Mobilinkd TNC4

Typical Price: $150

This is a great option for both mobile and home station use.

• Bluetooth 4.2 support (dual-mode EDR/LE) iOS Compatible 
• USB serial port 
• DCD and TX indicator LEDs 
• Powerful DSP and modem 
• High dynamic range ADCs and DACs 
• Buffered inputs and outputs 
• Input amplifier for improved input level matching across a wider range of radios 
• Optimized for packet radio & M17 data modes 900mAh rechargeable battery lasts for 2 full days 

The TNC4 is designed for both APRS and general packet use.  It is designed to interface with a wide range of mobile and base stations (as well as HTs). 

**NEW** the TNC4 uses a USB-C connector for charging and USB serial connections, support for M17 data modes, and a precision oscillator (TCXO) for improved symbol timing. The TNC4 is a 1200/9600 baud KISS TNC. It is capable of AFSK, GFSK and 4-FSK modulation. 

This tiny KISS packet modem is battery powered and can run for 48 hours of continuous use.  Small and lightweight, the TNC measures 80x42x15mm (3.1x1.6x0.6") and weighs in at just 48g (1.75oz).

$150Mobilinkd 

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Using Software to Send Digital Messages Over Radio

There are several software programs you can download for free which will also allow you to send digital messages over radio. Some examples are: VarAC , APRS, FLDigi, JS8Call, Winlink, WSJT-X.

We're going to look at VarAC which is chat over radio and Winlink (which is like email over radio) as we think these are the two easiest to use programs and give you a lot of abilities. 

Using VarAC for Peer to Peer Chat Over RF

VarAC uses the Vara HF and/or Vara FM modem software to communicate digitally between two radios. If your radio has a sound card, you don't need to have a TNC to communicate. 

From their website: 

VarAC is a free, modern HF P2P real-time chatting and emergency communication (EmComm) application for amateur radio operators, leveraging the VARA protocol.

So you'll have 2 sets of software running at the same time, the VarAC client which then uses one of the two Vara HF or FM (vhf/ufh) modem software. The VarAC software does all this automatically for you, but there is some setup you'll need to do in Vara HF/FM to get it to work right with your radio. 

If you have a radio that can connect to your PC via USB, and it has an internal sound card, then you point VarAC to the right COM port in your settings, and the software converts what you type (or very small files you can send) into digital signals and sends it over the air to the station you are communicating with. 

I wont get into the full step-by-step directions here (grab the manual from their website) but basically you tune to a frequency (40M or 20M work the best for me) and start to listen for stations calling CQ (CQ means "hey, anyone around want to talk?") or for Beacons (which are stations showing they are on the air, and seeing where they can be heard and who can hear the stations beacon, trackable 

You can download VarAC here: https://www.varac-hamradio.com/

You will also need to get Vara HF and Vara FM: https://rosmodem.wordpress.com/

Not necessary but helpful (I use it) is the FLRig software, which allows you to run your radio over USB: http://www.w1hkj.com/

Using Winlink for Radio Based Email

Theres another bit of software you should get, and that is Winlink. Winlink is like an email client that you can use in multiple ways - you can send email over the internet, or over the radio, or both!

Winlink is interesting because it can do peer to peer (meaning, directly from one radio to another) or you can connect to a local gateway. Think of a gateway as an interface between your radio and the internet. Its a radio system, usually with an antenna thats high up, which you connect to using your radio. It then takes your message and sends it into the internet. Your recipient can then either receive that message via the internet (you can send to any email address) or using their radio can connect to their local gateway and download it over RF. 

This is what the main Winlink mailbox looks like. You can open a "session" to chose the way you want to get your messages. Vara works again here. I use Vara FM to connect to my local gateway, and Vara HF to connect to remote friends directly or to gateways far away. 

Here is where you can download it: https://www.winlink.org/

Note: you will need to create a user account to use the system. 

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What Kind Of Radio Would I Need?

Ideally you'll get a radio that does the 3 main band types: HF, VHF, UHF. Most of the digital work I do is in HF on 40 meters and 20 meters using a 60 foot long wire antenna running from the end of my house up into a tree at around 12 feet. 

Yaesu FT-991A

 This is an incredible radio that is small enough to be portable but powerful enough to run at 100 watts and get your signal out there. You can run it off a car battery since it runs on 12 volts. Great for field use!

• Dynamic Real-Time Spectrum Scope
• Multi-Color Waterfall Display
• 160 Meters through 70 Centimeters - SSB/CW/FM/C4FM Digital/AM 
• 100 Watts (2 Meter / 70 Centimeter: 50 Watts) of Solid Output Power Performance 
• 3.5 inch TFT Full-Color Touch Panel Operation for Superior Operability and Visibility

$1150Amazon 

With a radio like this you will have 2 sets of antnnas going: one HF antenna and one VHF/UHF antenna.

Also don't forget, you will need a radio license issued by the FCC in the US to transmit with this radio, how to get your ham radio license. 

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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.

1. Ruggedized and Weather Resistant is better or,
2. 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.

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Ruggedized Laptops

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.

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Lighter Laptops

^{Img: Cargo Works 12" MACBOOK + IPAD SLEEVE}

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.

Pelican makes hard waterproof cases for laptops and companies like Cargo Works and 5.11 make tough tactical soft cases. There are a million different options here.

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.

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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?

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Final Thoughts

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.