Building a Ham Radio Teletext System: Reviving Aertel with Python and AX.25 for HF Communication

When the Irish broadcaster RTÉ announced the shutdown of its Aertel teletext service in October 2023 after nearly four decades of operation, it marked the end of an era for a technology that once brought news, weather, and TV listings into living rooms across Europe through the unused lines of analog television signals. For many, teletext was their first encounter with digital information—a curated, low-bandwidth service that felt almost magical in its simplicity. Now, in 2026, that same spirit of innovation is being rekindled not in Dublin or London, but in the basements, garages, and home workshops of amateur radio operators across the United States, where a growing number of hobbyists are experimenting with ways to revive teletext as a digital communication mode over the airwaves.

This resurgence isn’t about nostalgia alone. It’s driven by a practical desire to create robust, low-speed data channels that can operate under challenging conditions—think emergency communications during natural disasters when internet infrastructure fails, or remote field operations where bandwidth is scarce. The core idea, as explored in recent amateur radio publications, involves adapting the teletext standard for transmission over AX.25, the venerable packet radio protocol that has long served as the backbone of digital ham radio communication. By encoding teletext pages as AX.25 frames and transmitting them at 1,200 baud on VHF/UHF or 300 baud on HF, operators can send a full 40-by-24-character screen of multicolor text in as little as 11 seconds—a speed that becomes practical when pages are repeated and combined at the receiver to overcome noise and interference.

What makes this approach particularly compelling is how it mirrors the original teletext architecture: just as the BBC Micro once used the SAA5050 character generator chip to render teletext on screen with remarkably legible text despite limited pixel counts, modern implementations are leveraging open-source tools and software-defined radio to recreate the experience. One notable project, nicknamed “Spectel” by its developer, uses Python-based software to handle everything from page editing and AX.25 encoding to decoding and display, even incorporating the classic Bedstead font to replicate the blocky, nostalgic aesthetic of 1980s teletext. While the creator admits to ambivalence about relying on AI-assisted “vibe coding” to navigate the complex specifications of AX.25 and teletext, the result is a working prototype that demonstrates how aged ideas can find latest life when reimagined through contemporary lenses.

In cities like Chicago, where the amateur radio community has long been active in emergency preparedness and public service, this revival holds special relevance. The city’s dense urban landscape, coupled with its vulnerability to extreme weather events ranging from winter blizzards to summer heatwaves, creates scenarios where reliable, infrastructure-independent communication becomes critical. Local ARES (Amateur Radio Emergency Service) groups, already coordinated through the ARRL Illinois Section, routinely participate in drills simulating responses to events like tornado outbreaks or cyberattacks on municipal networks. Integrating a teletext-over-AX.25 system into these efforts could provide a lightweight way to disseminate situational updates—such as shelter locations, evacuation routes, or resource distribution points—without relying on cellular networks or the internet.

Beyond emergency use, the concept resonates with Chicago’s strong tradition of technical experimentation and STEM outreach. Institutions like the Museum of Science and Industry, which has hosted annual Maker Faire events and youth robotics competitions, could serve as natural partners for workshops introducing young people to digital communications through hands-on teletext projects. Similarly, the Illinois Institute of Technology, with its longstanding focus on engineering and applied sciences, has amateur radio clubs that have historically explored novel applications of packet radio and digital modes—making them ideal testbeds for prototyping and refining such systems in a collaborative, educational setting.

Given my background in amateur radio and digital communication systems, if this trend impacts you in the Chicago area, here are the three types of local professionals you need to connect with:

First, seek out Emergency Communications Specialists within the local ARES or RACES networks. These individuals aren’t just licensed operators—they’re trained in NIMS protocols, incident command structures, and power-independent operations. When evaluating them, look for documented participation in recent SET (Simulated Emergency Test) exercises, familiarity with Winlink or VARA FM for hybrid digital workflows, and a willingness to experiment with store-and-forward messaging systems that can tolerate intermittent connectivity.

Second, look for Digital Modes Mentors who focus on integrating legacy protocols with modern software. These are often found through Chicago-area ham radio clubs like the Chicago Radio Club or the Northern Illinois DX Association, where members regularly host technical nights on topics ranging from FT8 to APRS. The ideal mentor has hands-on experience with AX.25 implementations (such as those using Direwolf or sound card modems), understands the nuances of HF versus VHF/UHF propagation for data modes, and can guide you through setting up a TNC (Terminal Node Controller) or software-based alternative using a Raspberry Pi or similar SBC.

Third, consider STEM Education Coordinators** who bridge technical skills with community engagement. These professionals work at places like the Adler Planetarium’s youth astronomy programs or after-school initiatives run by the Chicago Public Library system, where they teach electronics, coding, and radio fundamentals. When approaching them, prioritize those who have led Arduino or Raspberry Pi workshops, understand how to scaffold complex topics for beginners, and observe amateur radio not just as a hobby but as a gateway to broader STEM literacy—especially when projects involve tangible outcomes like decoding a teletext page displaying real-time weather or a simple message sent across town.