Sigma’s Underground Communications with RipEX

Can high-speed, collision-free data really travel deep underground—through rock, dust, and tunnels? Thanks to Sigma and RACOM’s RipEX2, it can. And it’s changing the game for underground industries.

For over 30 years, Sigma has been a leader in underground communication solutions, providing dependable connectivity in some of the world’s harshest environments. But as industries evolve—mining, tunneling, and other subterranean operations increasingly demand higher data rates, greater capacity, and low-latency, reliable communications.

To meet these demands, Sigma developed its new Data Over Leaky Feeder (DOLF) system. The next step was to identify a future-proof radio modem capable of delivering high modulation rates and robust connectivity underground—where traditional radio signals struggle.

Following a thorough evaluation process, Sigma selected the RipEX2 radio modem, operating in the 150 MHz band, as the core communication engine for the DOLF system. Its support for 256QAM, Base Driven Protocol (BDP), and point-to-multipoint architecture made it uniquely suited for underground deployment.

System highlights include:

• Surface-based head-end RipEX2 units wirelessly communicating with numerous RTUs deep within tunnel networks
• Leaky feeder infrastructure to guide radio signals throughout complex subterranean paths
• 256QAM modulation used for high-capacity, high-efficiency transmission
• Base Driven Protocol (BDP) ensuring synchronized, collision-free communication
• Close collaboration with RACOM’s technical team to integrate a wide variety of Remote Terminal Units (RTUs) into the system

Thanks to the modem’s advanced sleep modes and rugged performance, it delivers long-term reliability in remote and hard-to-access underground locations.

The DOLF system powered by RipEX2 has delivered tangible operational benefits to Sigma and its clients:

• Stable, high-speed communication in environments previously limited to low-bandwidth or voice-only systems
• Dramatically improved data availability, reducing downtime and enhancing decision-making in the field
• Decreased maintenance needs, with robust hardware and reliable connections minimizing service disruptions
• Positive customer feedback, confirming that RipEX2 has exceeded expectations for performance and reliability

With this proven success, Sigma is now scaling the DOLF solution to new underground sites globally, confident in the long-term partnership with RACOM and the adaptability of RipEX2 technology.