How do you replace an aging RDS-based radio network across 1,900 km of water and sewer infrastructure – without service outages and while preparing for fully IP-based SCADA? For Vodovody a kanalizace Hradec Králové, a.s. (VAK HK), the answer was a hybrid network built on RipEX and M!DGE.
https//www.racom.eu/eng/case/hybrid-solution-modernised-water-management
Challenge: Aging Legacy Radios and the Need for a Future-Proof SCADA Network
VAK HK provides drinking water and wastewater services to more than 170,000 residents, operating:
- over 1,350 km of water mains
- 550 km of sewer infrastructure
- dozens of pumping stations, reservoirs and treatment facilities
The existing SCADA communication system relied on CONEL CDA radios using serial RDS protocol. With end-of-life support for CONEL devices, VAK HK needed:
- a modern, reliable IP-ready network
- seamless migration with no outages
- long-term cybersecurity and SCADA flexibility
- a design that supports fully redundant data centres
A hybrid network combining radio and LTE was identified as the optimal approach.
Solution: RipEX and M!DGE Form a Unified Hybrid Architecture
After evaluating several vendors, VAK HK determined that RACOM was the only supplier able to meet all requirements.
Key reasons:
- RipEX and M!DGE share software logic and management principles
- routing managed centrally by one RipEX, simplifying application interfaces
- seamless hybrid operation with RipEX providing RF access and M!DGE providing LTE backup
- highly reliable Flexible protocol for long radio paths
- RACOM’s Migration Solution enabling parallel legacy and new-network operation
- RACOM-manufactured cabinets providing a complete turnkey deployment
Migration Strategy: Zero Downtime and Full Parallel Operation
Migration used two frequencies:
- one for the legacy CONEL network
- one for the new RipEX network
Key repeater sites were equipped with duplexers, enabling both frequencies to operate simultaneously. This allowed a phased migration during normal maintenance windows.
High-Availability Hybrid Operation
27 primary sites, classified as critical, were equipped with both RipEX and M!DGE.
Workflow:
- Legacy RTUs connect to RipEX via serial or IP.
- RipEX handles all routing and path selection.
- If LTE is available, RipEX backup routing automatically diverts traffic through M!DGE.
- The M!DGE segment uses GRE tunneling over a private APN, terminated on a Cisco ASR at the customer’s data centre.
Result: near-100% availability across all primary sites.
69 secondary sites were migrated to RipEX only, using RDS serial or Modbus TCP.
All equipment was delivered in RACOM-built outdoor/indoor cabinets for consistent installation quality.
Results: A Modern, Resilient and Scalable Water Utility Network
The hybrid RipEX + M!DGE solution delivered:
- seamless migration without outages
- dramatically higher availability through LTE backup
- unified routing logic and simplified SCADA integration
- readiness for TCP/IP and future report-by-exception
- long-term reliability for both primary and secondary sites
Phase two is already planned and will include:
- two geographically separate, fully redundant data centres
- a private MPLS network interconnecting data centres and relay points
The hybrid RACOM solution now forms the communication backbone of one of Czechia’s largest water utilities – modern, resilient and ready for the next decade of SCADA evolution.
