Let’s start with the hardware
When talking about digital modes in amateur radio, the first element to consider is the computer. The good news is that you don’t need a modern or particularly powerful machine: the most commonly used software, such as WSJT-X, fldigi, or JS8Call, has very modest requirements compared to today’s mainstream applications.
Choosing hardware therefore becomes a balance between three key factors: reliability, availability of ports (especially USB), and cost.
A dedicated station: the recommended choice
Many radio amateurs choose to use a computer dedicated exclusively to radio. This is not mandatory, but it offers several practical advantages.
A dedicated system avoids unwanted updates or changes that could interfere with software, keeps audio and serial port configurations stable, and reduces the risk of issues related to RF interference or conflicts with other devices.
In practice, even an older machine can become a reliable platform, always ready to use and without the need for constant adjustments.
Linux and real requirements
This is where Linux shows one of its strengths.
Modern distributions, especially if lightweight and properly configured, run easily even on hardware that is 10 or 15 years old. The main amateur radio software is well supported and easy to install.
As a concrete reference: WSJT-X minimum requirements (dual-core CPU around 1.5 GHz and 2 GB of RAM) are easily met by virtually any PC, even outdated ones.
In other words, in practice hardware is rarely a limiting factor.
The value of refurbished hardware
One of the most interesting solutions is the refurbished PC market.
These are often professional-grade machines designed for continuous operation, now available at very affordable prices. Models such as ThinkCentre, Optiplex, or EliteDesk offer higher build quality than consumer products, even in compact versions (SFF, MFF, or USFF).
The only aspect to pay attention to is the number of USB ports, which are always useful in radio applications.
With some searching, it is easy to find systems with 64-bit third- or fourth-generation CPUs, more than adequate for the purpose. For just a few dozen euros, a complete workstation can be built.
Mechanical drives can still work, but replacing them with a small SSD results in a faster, quieter, and more pleasant system to use.
It is an economical but also smart choice that gives new life to otherwise perfectly usable hardware.
Raspberry Pi and single board computers
In recent years, devices such as Raspberry Pi and other single board computers (SBCs) have also become popular in amateur radio. They are compact, low-power, and well suited for dedicated builds.
However, it is worth making a realistic assessment: considering power supply, case, and storage, the total cost is often similar to, or even higher than, that of a refurbished PC. In addition, at the same price point, performance may be lower, especially when running multiple applications simultaneously.
This does not mean they are a bad choice—on the contrary. SBCs are particularly useful when size, power consumption, and portability matter: mobile stations, portable operations, or remote installations.
In these cases, they offer advantages that are difficult to achieve with a traditional PC.
For this reason, HamLinux 3 includes a specific mode designed to simplify use even in “field operation” conditions.
Installation: everything is easier today
Installing Linux today is a straightforward process.
You simply download a system image, write it to a USB stick, and boot the computer from it. Within minutes, you get a working system with ready support for audio, USB, and common peripherals.
For beginners, a prebuilt image such as HamLinux can be used directly. It is specifically designed for amateur radio use and already includes:
- software for the main digital modes
- preconfigured audio and USB device support
- station control tools
- a ready-to-use operating environment
This allows you to start operating within minutes, without manually installing or configuring everything.
Connecting the radio to the computer
To use digital modes, the radio and computer must be connected on two levels:
- audio, for transmitting and receiving signals
- control, via the CAT system (Computer Aided Transceiver)
Both aspects can be handled easily, especially with modern transceivers.
Modern radios: everything in one cable
Many modern radios already include a built-in USB interface that handles both audio and CAT control.
In these cases, a single USB cable between radio and computer is enough: the simplest and most immediate solution.
Older radios: no problem
Older transceivers require a few additional components, but nothing complicated.
For audio, an external interface is used—often inexpensive—while CAT control requires a USB-to-serial adapter compatible with the radio.
The most common and reliable chips are FTDI or CP2102-based devices, and the connection follows the radio manual.
Digital interfaces: buy or build
Ready-made interfaces exist and greatly simplify connections, but they can be relatively expensive.
Alternatively, with some experience, it is possible to build your own solutions that are cheaper and perfectly adequate.
This is a typical amateur radio approach: it depends on how much experimentation you want to do.
The audio part
For audio, a simple USB sound adapter is often sufficient, as long as it supports 48 kHz sampling, which is standard for most software.
Connection to the radio is made using good-quality shielded cables. In a properly grounded station, no special measures are usually required.
Unwanted RF and ferrites
A common issue is RF interference on audio or USB cables, which can disrupt decoding.
A practical solution is the use of ferrite cores placed on the cables: they do not eliminate the cause of the problem, but significantly reduce interference.
For HF, mix 31 and 43 materials are most effective.
In summary
Building a digital mode station today is simple and inexpensive.
With:
- a refurbished PC
- Linux (or directly HamLinux 3)
- a USB audio interface
- a CAT control adapter
you can build a complete, stable, and efficient station.
And with modern radios, often a single cable is truly enough to get on the air.
In the photo: the dedicated refurbished PC of my station is a ThinkCentre M91 USFF (2013), Core i5-3470 CPU, 4 GB RAM, and a 120 GB SSD.