It is clearly vital that the transmitter network must stay on air consistently. Interruptions in broadcasting are at the very least reputationally damaging, and frequently result in a significant loss of revenue.

A transmitter network that relies upon a high level of preventative and emergency maintenance is not cost-effective. Nor is the ability to resolve recurrent problems quickly. Far better is to design a transmitter which is in itself highly reliable, with internal resilience and the ability to self-repair.

In developing its new generation of digital transmitters, Rohde & Schwarz took the approach that operators would prefer a transmitter that did not cause problems, one that would stay on air consistently, with minimal maintenance and operator intervention. And alongside the transmission technology, there must also be an advanced control layer, using intelligence to achieve unprecedented resilience.

Minimizing reasons for maintenance

The choice of the cooling concept of a transmitter has a massive impact on later maintenance efforts and operational expenses. From a resilience point of view, liquid cooling is preferred. It means heat from the transmitter can be moved out of the building for dissipation, reducing the need for and the dependency on maintenance-intensive air conditioning systems, which is expensive both to install and to run.

Liquid cooling must be incorporated into a transmitter’s design right from the beginning in order to get the full potential of that cooling concept. Fully sealed amplifiers without moving parts like fans will greatly reduce the risks of corrosion and faults, removing the need for regular routine air filter cleaning or replacement.

That is possible only with highly stable power supplies directly cooled by the liquid circuit, creating a much more stable temperature environment for critical components. Coupled with high-quality pumps and long-life heat exchangers the architecture minimises maintenance efforts and repairs, which is of major importance when transmitters are located in remote areas.

Self-reliant operation

On top of this are monitoring and control abilities – a control layer, designed to deliver consistent performance without extensive user interaction.

Just as the exciters are duplicated for resilience, so too the system control functions should be in a distributed architecture, to eliminate single points of failure.

This control system has to be designed for self-reliance. It should automate all the normal functionality of the transmitter, and include intelligence for a high degree of autonomous problem-solving to keep the system on air even if parts of the transmitter show faults. That starts with active self-monitoring of output power and signal quality, as well as tracking efficiency targets.

Automated monitoring and control must also track operational parameters, to ensure that the transmitter consistently meets the defined performance boundaries and limits, self-adjusting where possible, and reporting any violations to the central network control.

Such a smart design with its reliance on a high level of automation reduces complexity, which makes the transmitter largely self-sustaining in staying on air. Status reports are continually delivered to the Network Operation Center, where engineers can rely on the transmitter to operate stably, only requesting human intervention when needed.

Anything other than very high availability is not acceptable in a transmitter. The broadcast network cannot be off air because of a transmitter component failure, especially given that some transmitters will inevitably be in remote locations which repair teams can take hours to reach. Placing operational staff at every transmitter just in case maintenance is needed is an excessive expense, so the complete system must be designed for resilience and non-stop operation. Excellence in hardware design, monitoring and control functionalities as well as self-reliance are the keys to deliver this goal.

There is no doubt that terrestrial network operators are experiencing significant challenges. Rohde & Schwarz, widely recognised for its engineering excellence, understands and is ready to support network operators to deliver innovative new functions while providing substantial improvements in resilience and simplified operations. The result is significant savings in both capital and operational expenditure over the lifetime of the transmitter network, delivered through the proven innovation, quality and support offered by Rohde & Schwarz.