How do you deliver real-time split-time data for a world-class ski marathon across 15 km of mountainous terrain – during a day when public mobile networks collapse under the load of thousands of spectators? For the timing specialists at On Line System, the answer was RipEX.
https//www.racom.eu/eng/case/reliable-split-time-transmissions-for-jizerska-50
Challenge: Public Mobile Networks Overloaded, Cables Impossible, Terrain Difficult
Spectators see split times live on big screens and TV broadcasts, but few realise the technical obstacles behind them – especially in large outdoor events such as:
- long-distance cross-country skiing
- mass running events
- cycling marathons
- orienteering
- triathlons
For Jizerská 50, part of the Visma Ski Classics series with nearly 5,000 competitors, reliable split-time transmission is essential.
Historically, On Line System relied on 3G/4G, but they increasingly suffered:
- mobile network overload due to thousands of spectators
- unreliable coverage in remote forest sections
- unpredictable delays
- occasional loss of split-time packets
A private radio network was needed – one that would operate independently of public infrastructure.
Solution: RipEX 400 MHz Radio Network with Flexible Protocol and Multi-Hop Routing
In 2018, On Line System switched to RipEX for split-time transmission.
The setup included:
- three fixed timing points on the course (unchangeable due to event logistics)
- radio links covering up to 15 km
- three hops required for one of the segments
- 25 kHz channel
- robust 4CPFSK modulation
- Flexible protocol for collision-free routing
- reliable TCP/IP transmission of 70-byte packets
To prevent overloading the network, the application queues each packet until a TCP acknowledgement is received from the central timing server.
Robustness Proven Under Real-World Race Conditions
During the race:
- all three timing locations transmitted simultaneously
- none of the timing stations could “hear” each other
- two repeaters were involved
- potential for collisions was extremely high
Yet RipEX handled:
- simultaneous multi-hop transmissions
- packet collisions
- queueing and retransmissions
- long distances and forested terrain
– all without degrading timing accuracy or throughput.
Results: Reliable Real-Time Data for a Premier Sporting Event
With RipEX, On Line System achieved:
- secure and stable split-time transmission
- independence from overloaded cellular networks
- real-time delivery to the event centre and TV broadcast crew
- a stress-free race day for timing operators
- a reusable radio setup for future sporting events
As Petr Blažej, owner of On Line System, said:
“We are delighted with the performance levels achieved by RipEX throughout the event. Knowing that the data was being transmitted over a secure and robust link made the whole event a more relaxing experience for us.”
RipEX now plays a key role in ensuring the timing reliability of one of Europe’s most famous long-distance ski races.
