Packet Radio – Building a Station (Shopping List)
This is made to be a decent go-to reference for those new to packet radio looking to build a station. This by no means encompasses all products. The item’s I’ve listed here are a reflection of the modern packet radio landscape. If you are new to Packet Radio, start here to get a grasp on what the modern landscape of Packet radio looks like, check this out. The following post here will give you a good Shopping list for building a packet radio station.
Radio
We can’t have packet radio without a radio can we? The good news is that we can make a “packet radio” out of just about anything with a hand mic. The general rule for shopping for packet radios is to make sure the one you find has some documentation regarding it’s “pinout”. If we can get audio in, and out of the radio, as well as toggle the PTT(Push to talk) line, we can make it do packet. The only true exception is that 9600 baud packet (the higher end of typical packet radio speeds) usually requires a special data port. Most radios will show 9600baud packet as a feature. I’ll list a few radios here I personally recommend checking out. Some radios also come with a TNC (like the Kenwood TH-D75A), which we will talk about next.
I’m going to list a few radios here for a decent price spectrum. Just know that there is no way to possible list all radios capable to packet. The only radios I’ll list here are still being made. There are a lot of great packet radios with built in TNC’s that are discontinued, but that doesn’t fit with the “Modern Packet Radio” series. Most HF radios now have built in sound cards, so packet isn’t an issue. Just make sure you can find an audio interface online for the one you’re looking at. Many newer Yaesu radios come with APRS functionality, but lack the ability to use the onboard TNC. I’ve left them out for this reason.
- Baofeng UV/FH XX – 30$-70$ – Everyone knows the Baofeng. The Baofeng can also do packet radio operation along side being a controversial subject. Although a $30 radio does not make the best packet radio station, it can get the job done when combined with an audio interface with PTT like the digirig. With 5-8 Watts of power, and a battery, it makes a decent “cheap” mobile packet radio.
- Retevis RT-95 $119 – Moving on up to a mobile rig, we have the RT-95. This is my permanent at-home packet station. It is still well within the “budget” line of radios, but 25 Watts is a solid amount of power for a packet node. The only quirk is a strange pinout for the audio interface. But once again, digirig saves the day with a compatible cable for the radio.
- Yaesu FTM-6000R – $300 – A Jump up to the FTM-6000R gives us 50 watts of power output on VHF/UHF. But what makes the radio on the list is the 9600baud packet ability.
- Kenwood TH-D75A $750 – A massive price to pay for a 5 watt handheld. The only reason I’ve listed it here is because it is one of the only currently manufactured radios with a built in usable TNC. It truly is plug and play into your computer via USB for packet operation.
- HF Radios – There are not many “packet focused” HF radios on the market. Your best bet is to look for one that a TNC or digital interface can be connected to easily. If you want quicker baud rates, look for one with a data jack capable of 9600 baud, although these probably aren’t being made yet. Personally, I use the FT-891 as my packet node, and direwolf interfaces easily with it’s PTT Port via Serial connection.
TNC (Terminal Node Controller)
The first thing you need to consider when building a packet radio station is the TNC. (Terminal Node Controller). The TNC is important because it sets the standard on how fast your station can operate (in baud), and also determines what radio interfaces will be readily available as an “off the shelf” solution. The good news is, you don’t need to BUY a piece of hardware anymore at all. TNC’s can also some in software. One such very popular packet radio TNC software is direwolf. An example of a modern day hardware TNC would be the Mobilinkd, a Bluetooth enabled TNC.
Here is a list of popular software and hardware TNC’s with some pros and Cons. I will not be providing links to discontinued TNCs. This is meant to be usable well into the future. I personally recommend dire wolf, and you can find a guide to gettign it running here.
Software TNCs:
- Direwolf – Very versatile open source modem capable of variable baud rates of anywhere between 300-9600. It can also function as a self contained ARPS IGate and Digipeater. It has built in PTT support for many existing digital interfaces. Can easily be ran headless for server environments.
- VARA – While some don’t consider this a traditional “packet” modem, this TNC does feature a KISS interface much like Direwolf and Soundmodem. This means it can be used with most of the packet applications we use today. It is a closed source modem known for it’s high dataspeeds. The faster speeds are locked behind a paywall.
- Soundmodem – A closed source software TNC with baud rates of 300-9600. It features a GUI waterfall which can be handy for HF packet operation when you aren’t running a fixed signal.
Hardware TNCs:
- Mobilinkd TNC4 – $149.95 – A Bluetooth, battery enabled TNC made to work “on the go”. It features either 1200/9600baud rates, and indicator lights for RX/TX. It also supports M17 data modes. Mobilinkd will work with Bluetooth devices like android cellphones, and also features a USB-C port for PC Serial connections. The shop also contains many cable connections for radios ready to plug and play. Not great for current HF operation due to speeds.
- Kantronics KPC-3 Plus – $249.00 – Contains built in software for hosting BBS(Buliten Board systems) and mail forwarding. Support for 1200 baud VHF/UHF packet operation.
- Kantronics KAM-XL – $465.00 -Contains built in software for hosting BBS(Buliten Board systems) and mail forwarding. Can be used of VHF/UHF, as well as HF, and has the ability to cross repeat packets across 2 ports. The modem also has support for other digital modes such as PACTOR 1, PSK31, and RTTY.
- NinoTNC – $70 – A TNC made as a Pi-Hat. Supports 300-9600 HF/VHF/UHF packet operation. It includes built in support for a more efficient X.25 protocol, IL2P. A Raspberry pi is required, as well as your own radio cable construction.
Digital interface
There are a lot of options when it comes to choosing your digital interface. The digital interface here is the hardware that connects your radio to your TNC. If you are using a software TNC, this means connecting your radio to a sound card. If you are using a hardware TNC, this means connecting your radio to your actual TNC hardware. There are some interfaces made to be modular with built in sound cards, where only a cable needs swapped out when changing radios. Remember that the digital interface only needs audio in, and out of your radio, as well as the ability to toggle the radios transmit function (PTT). It’s also possible your radio already has a built in PTT+Sound card interface if it has a USB connection. Check your manual.
- Digirig $50-$80 – This is a modular interface made to work with software TNCs. The idea is you buy the digirig device, which has a built in soundcard, PTT and rig control via CAT circuitry. Then buy or make a cable for your radio. This is my favorite option, as the store contains cables for all of my radios, and the modular interface means all I have to do is swap each cable out between radios.
- SignaLink – $150 – Provides a sound card to your computer. It features adjustable knobs for TX/RX levels, which can be helpful to adjust input/output signal instead of using your computers volume slider. For PTT, it implements VOX to toggle the PTT on your radio side, which isn’t the most efficient. Swapping radios also involves swapping a jumper cable within the equipment. Overall, the digirig beats it in every category at half the price.
- Rigblaster – $69-$209 – Has several models building in functionality. The Rigblaster provides a sound card interface, and PTT to the computer. The higher end models also feature microphone pass though. Some higher end models also feature adjustable knobs like the signalink. Overall, the cheapest model is more expensive, with less features than the digirig, while the highest end does everything the digirig can do and the more.
- Custom Interfaces – $??? As long as we can get audio in and out of our radio, as well as toggle PTT, we can make our own digital interface. There are also many custom made interfaces online for different radio models. Just know that at the end of the day, we want a soundcard to our radio, and a serial port for PTT preferably.
Computer / Raspberry PI / Cellphone
The last thing you’re going to need is a computer to interface with. Different TNC’s will allow connection to different devices. We will talk about a few generic computing options below.
- Cellphone $50- $200 – An android cellphone will get you the most use in packet radio. There is more TNC application support all around, and you have the ability to plug a soundcard into many of them that support host mode. This is the best option when using the mobilinkd mentioned above. A cellphone will mostly limit you to APRS/Winlink packet at the moment, but with some hacks you may be able to get more functionality.
- Latptop/Desktop – $100-$500 The most versatile option. This will support just about any TNC and any software allowing you to run whatever you like.
- Raspberry Pi – $30-$150 Pretty close in terms of functionality of the Laptop/Desktop, but limited to ARM compatible software. A special mention use of the Pi when it comes to packet radio would be DigiPi, a project by KM6LYW which turns a raspberry pi into a fully featured plug and play packet radio systems (plus lots of extra goodies).
Conclusion
Hopefully this little list has been helpful when shopping for parts to build your own packet radio node. This by no means covers everything, but hopefully is enough to get you thinking about the parts needed. If you have any suggestions to add for any of the parts above that are still being made, please let me know down in the comments.